Effect of azithromycin on airway inflammation and airway mucus hypersecretion in rats with chronic obstructive pulmonary disease

AIM: To observe the effect of azithromycin on the rats with chronic obstructive pulmonary disease (COPD), and to explore the underlying mechanism about the airway inflammation and mucus hypersecretion. METHODS: Male SD rats were randomly divided into normal control group, COPD model group, azithromycin treatment group. The COPD model was established by the method of cigarette smoking combined with intratracheal injection of LPS. Pathological changes of the bronchi and lung tissues of the rats were observed with HE staining. Pulmonary ventilation function in the rats was detected with pulmonary function instrument. The levels of IL-8, IL-17 and TNF-α in bronchoalveolar lavage fluid (BALF) were measured by ELISA. The expression of MUC5ac and TLR4 at mRNA and protein levels in bronchi and lung tissues was determined by real-time PCR and Western blot.RESULTS: HE staining showed that the changes of bronchi and lung tissues in model group were consistent with typical pathological manifestations of COPD. Compared with model group, these changes were alleviated in treatment group. The pulmonary functions in model group were significantly decreased compared with control group. The levels of IL-8, IL-17 and TNF-α in the BALF in model group were significantly increased compared with control group (P <0.05). The expression of MUC5ac and TLR4 at mRNA and protein levels in model group was significantly higher than that in control group (P <0.05). Compared with model group, the degree of the descent in pulmonary function in treatment group was significantly lessened. Compared with model group, the levels of IL-8, IL-17 and TNF-α in treatment group were significantly inhibited (P <0.05). Furthermore, the expression of MUC5ac and TLR4 at mRNA and protein levels in treatment group was significantly lower than that in model group (P <0.05). CONCLUSION: Azithromycin decreases the levels of IL-8, IL-17 and TNF-α in the BALF of COPD model rats, inhibits the protein expression of MUC5ac and TLR4 in the lung tissues, thus playing a preventive and therapeutic role to reduce airway inflammation and airway mucus hypersecretion.     

Effect of endothelin-1 on inflammation and oxidative stress in COPD

AIM:To investigate the effect of endothelin-1 on inflammation and oxidative stress in chronic obstructive pulmonary disease (COPD). METHODS:Healthy non-smokers (30 cases), healthy smokers (30 cases) and COPD patients (29 cases) were collected and induced to produce sputum. The concentration of endothelin-1 in the induced sputum was detected. The model of emphysema was established by cigarette smoke extract to stimulate SD rats. Endothelin A receptor antagonist BQ123 and non-selective endothelin receptor antagonist bosentan were used to intervene with the model rats. The experiment was divided into control group, cigarette-treated group, selective antagonist group and non-selective antagonist group. The protein levels of cleaved caspase-3 in the lung tissue were determined by Western blot. Gelatin zymography was used to analyze the activity of matrix metalloproteinase-2 (MMP-2) and MMP-9 in the lung tissue. The levels of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were measured by ELISA. The bioantioxidant power (BAP) was detected by BAP assay kit. RESULTS:The concentrations of endothelin-1 in induced sputum of healthy smokers and COPD patients were significantly higher than that of healthy non-smokers (P<0.05), and the level of endothelin-1 in COPD patients was significantly higher than that in healthy smokers (P<0.05). The levels of cleaved caspase-3, MMP-2, MMP-9, TNF-α and IL-1β in the lung tissues from cigarette-treated group were significantly higher than those in control group (P<0.05). The endothelin A receptor antagonist significantly inhibited the levels of cleaved caspase-3, MMP-2, MMP-9, TNF-α and IL-1β (P<0.05). The serum BAP in cigarette-treated group was significantly lower than that in control group (P<0.05). However, endothelin A receptor antagonist significantly increased serum BAP (P<0.05). CONCLUSION:Endothelin-1 may play an important role in the development and progression of COPD through regulating apoptosis, matrix metalloproteinase activity, inflammation and oxidative stress.     

Endogenous hydrogen sulfide regulates oxidant/antioxidant balance in rat with chronic obstructive pulmonary disease

AIM: To investigate the role of hydrogen sulfide (H₂S) in the protection against oxidative stress in rats with chronic obstructive pulmonary disease (COPD).METHODS: The rat model of COPD was established by cigarette smoking (CS) combined with lipopolysaccharide (LPS) instillation. Thirty-two healthy male Sprague-Dawley rats were randomly divided into 4 groups: control group, CS+LPS group, CS+LPS+NaHS (H₂S donor) group and CS+LPS+PPG (DL-propargylglycine, an inhibitor of cystathionine-γ-lyase) group. After 30 days, the lung functions of the rats were measured, the histological changes of lungs were observed under light microscope and the pathological scores were calculated. The H₂S level in plasma and the protein expression of cystathionine-γ-lyase (CSE) in the lung tissues were measured. The content of malondialdehyde (MDA), the activity of superoxide dismutase (SOD) and catalase (CAT) were detected to reflect oxidative stress.RESULTS: Compared with control group, the peak expiratory flow (PEF) decreased by 24% and intra-pressure (IP) increased by 66% in CS+LPS group. The pathological scores of the lung tissues also increased. Compared with CS+LPS group, no change in the lung function was observed after given NaHS or PPG, but the pathological scores decreased in CS+ LPS+ NaHS group. Compared with control group, the content of H₂S in plasma was increased by 26% on day 16. Compared with CS+LPS group, the content of H₂S in plasma of CS+LPS+PPG group was decreased by 22% after 30 days. Compared with control group, the protein expression of CSE increased, and no statistical difference among CS+LPS group, CS+ LPS+ NaHS group and CS+LPS+PPG group was observed. Compared with control group, MDA content in the lung tissues was increased by 24% in CS+LPS group, the activity of SOD was increased by 47% and the activity of CAT was increased by 52%. Compared with CS+LPS group, the MDA content in CS+LPS+NaHS group was decreased by 21%, and no statistical difference in the activity of SOD and CAT was observed. The activity of SOD decreased by 33% after given PPG.CONCLUSION: H₂S plays a role as anti-oxidant in the rats with COPD. The CSE/ H₂S pathway may be involved in the development of COPD.     

Effects of non-invasive positive pressure ventilation on respiratory mechanics and central drive in sleeping patients with chronic obstructive pulmonary disease

AIM: To evaluate the effects of non-invasive positive pressure ventilation (NIPPV) on respiratory mechanics and central drive in sleeping patients with chronic obstructive pulmonary disease (COPD). METHODS: Sixteen moderate-to-severe COPD patients in the acute exacerbation period, admitted to Zhujiang Hospital from October 2010 to October 2011, were chosen in the study. The routine pulmonary function test was performed, and all patients under relatively stable conditions after NIPPV treatment were monitored by respiratory mechanics, diaphragm electromyogram and polysomnography in waking and sleeping states when they were spontaneously breathing or receiving NIPPV. Other physiological parameters were recorded and calculated on a continuous basis in time sequence for 30 min. RESULTS: When COPD patients were spontaneously breathing in sleeping state as compared with waking state, there was no significant difference in respiratory rate (RR) and the ratio of inspiratory time to total respiratory cycle time (T_i/T_tot), but there were significant decreases in tidal volume (V_T), minute ventilation(V_E), mean inspiratory flow (V_T/T_i), dynamic lung compliance (C_Ldyn), root mean square (RMS) of diaphragm myoelectrical voltage and pulse blood oxygen saturation (SpO₂). Meanwhile, there were significant increases in airway resistance (R_aw), pressure-time product (PTP) and end tidal carbon dioxide pressure (P_ETCO₂). When COPD patients received NIPPV as compared with spontaneous breathing in waking state, there was no significant difference in RR, V_T and V_E, but there were significant increases in V_T/T_i, C_Ldyn and SpO₂.Meanwhile, the reductions of T_i/T_tot, R_aw, PTP, RMS and P_ETCO₂ were also significant. When COPD patients received NIPPV as compared with spontaneous breathing in sleeping state, there was no significant difference in RR and RMS, but there were significant increases in V_T, V_E, V_T/T_i, C_Ldyn and SpO₂.Meanwhile, the reductions of T_i/T_tot, R_aw, PTP, and P_ETCO₂ were significant. CONCLUSION: The abnormal changes of respiratory mechanics and the reduction of central drive were the main reasons for hypopnea and hypoxemia in sleeping COPD patients. On the one hand, NIPPV can significantly improve respiratory mechanics of COPD patients in waking and sleeping states by reducing airway resistance and work of breathing, which resulting in better respiratory response and ventilation output. On the other hand, NIPPV can significantly reduce the central drive of COPD patients in waking state, which can not do the same in sleeping state.     

Cigarette dust particles induced lung function injury of chronic obstructive pulmonary disease in mice

AIM: To investigate the pathogenesis of chronic obstructive disease (COPD) in mice by using nasal drip of cigarette dust particles (DSP) induced pulmonary function damage model.METHODS: BALB/c mice were randomly divided into control group, LPS 100 mg/L group, DSP 0.75 mL/L group, DSP 1.5 mL/L group and DSP 3 mL/L group for 30 days. The method of nasal drip was used for 30 days to establish the COPD model. Rrs, Ers, Crs, Est, Cst, P-3/8Rn, P-3/8G and P-3/8H were measured for evaluating lung function of the mice in each group by the method of FlexiVent. The effect on the increase of airway resistance induced by methacholine (Mach) was determined using main bronchial rings by Myograph method. The HE, Masson and Resorcinol fuchsin staining of mouse tracheas and lung tissues were conducted. RESULTS: Continuous nasal drip with DSP for 30 days increased Rrs, Ers, Est, P-3/8Rn and decreased Crs, Cst, P-3/8G and P-3/8H in the mice. DSP significantly shifted the dose-effect curve of tracheal contraction induced by Mach to the left, increased the sensitivity of the airway to Mach, and significantly increased the maximal contractile airway effect of Mach. Exposure to DSP caused fibrosis of airway subepithelial, deposition of collagen in the airway basement membrane under the reticular plate, induced reticular plate thickening, pulmonary bronchial lumen serious deformation, and the inflammatory cell infiltration in the lung of mice. Significantly increased alveolar wall muscle fibers and collagen fibers were also observed. CONCLUSION: The lung function and pathomorphological changes of COPD mice induced by 30 days nasal drip of cigarette dust particles were similar to those of human COPD.     

Protective effect of salidroside on rats with hypoxic pulmonary hypertension by suppressing oxidative stress

AIM: To study whether salidroside plays a protective role in hypoxia-induced pulmonary hypertension by suppressing oxidative stress. METHODS: Sprague-Dawley rats were randomly divided into 4 groups:normoxia (N) group, hypoxia for 4 weeks (H₄) group, low-dose salidroside (hypoxia for 4 weeks and treatment with salidroside at 16 mg/kg, H₄S16) group and high-dose salidroside (hypoxia for 4 weeks and treatment with salidroside at 32 mg/kg, H₄S32) group. The mean pulmonary arterial pressure (mPAP), the weight ratio of right ventricle/(left ventricle+septum)[RV/(LV+S)] and vessel wall area/vessel total area (WA/TA) were evaluated. The levels of malondialdehyde (MDA) in the serum and lung tissues were detected by colorimetric method. The levels of 8-iso-prostaglandin F_2α (8-iso-PGF_2α) in the serum and lung tissues were measured by ELISA. The activity of superoxide dismutase (SOD) in the serum was analyzed by hydroxylamine method. The expression of NAPDH oxidase 4 (NOX4) and SOD1 in the lung tissues was determined by Western blot. RESULTS: Compared with N group, the levels of mPAP, RV/(LV+S) and WA/TA in H₄ group were significantly increased, which were apparently attenuated by salidroside injection in a dose-dependent manner. Meanwhile, salidroside administration apparently decreased the levels of MDA and 8-iso-PGF_2α in the serum and lung tissues, as well as the expression of NOX4 in the lung tissues. Besides, compared with N group, the activity of SOD in the serum and the expression of SOD1 in the lung tissues in H₄ group were significantly decreased, while administration of salidroside increased the activity of SOD in the serum and the expression of SOD1 in the lung tissues in a dose-dependent manner. CONCLUSION: Salidroside protects the pulmonary vessels from remodeling and attenuates hypoxia-induced pulmonary hypertension by inhibiting oxidative stress.     

Expression of hypoxia-inducible factor 1α in pulmonary tissues from patients with chronic obstructive pulmonary disease

AIM：To study the expression of hypoxia-inducible factor 1α (HIF-1α) in pulmonary tissues from patients with chronic obstructive pulmonary disease (COPD) μg/L and its effects on the pathogenesis of COPD. METHODS：Pulmonary tissues were obtained from 32 subjects (16 patients with COPD and 16 without COPD as controls) who were undergoing single or bilateral lobectomy or wedge resection for lung cancer. The specimens were obtained as far away from the cancer foci (≥8 cm) as possible. The expression of HIF-1α protein in pulmonary tissues was measured by Western blotting and enzyme-linked immunosorbent assay (ELISA). RESULTS：The expression of HIF-1α protein in pulmonary tissues from controls and COPD patients was as follows: (0.96±0.43) μg/L and (0.16±0.07) μg/L (ELISA, P<0.05); 0.71±0.22 and 0.53±0.15 (Western blotting, P<0.05). Furthermore, the level of HIF-1α protein in pulmonary tissues from mild and moderate COPD patients was obviously higher than that from severe COPD patients (P<0.05). CONCLUSION：HIF-1α may play an important role in the progress of COPD.     

Diagnostic value of Th17 cells in symptom severity and prognosis of chronic obstructive pulmonary disease

AIM: To observed the correlation between Th17 cell level and the symptom severity and prognostic factors of chronic obstructive pulmonary disease (COPD), and to explore the clinical application value of Th17 cell level in assessing the prognosis of patients with COPD. METHODS: The patients with diagnosed COPD (n=110) in our hospital during May 2013 to December 2014, and 40 healthy subjects were enrolled in the study. According to the Global Initiative for Chronic Obstructive Lung Disease (GOLD), the COPD patients were divided into group A (low risk, less symptoms), group B (low risk, more symptoms), group C (high risk, less symptoms) and group D (high risk, more symptoms), which were given inhaled corticosteroid/long-acting β₂ agonist or corticosteroid/long-acting β₂ agonist+long-acting antimuscarinic agent treatment for 3 months. The proportion of Th17 cells, cytokines (IL-17 and IL-6), the COPD assessment test (CAT) score, age, body mass index, pulmonary function and the times of acute exacerbation of COPD in previous 1 year were observed before and after treatment. The correlation analysis between the level of Th17 cells and other clinical characteristics was performed. RESULTS: Th17 cell, IL-17 and IL-6 levels in COPD group were significantly higher than those in control group (P < 0.05). With the increase in the severity of COPD symptoms, Th17 cells, cytokines (IL-17 and IL-6) and CAT score in groups B and D were significantly higher than those in groups A and C (P < 0.05). The univariate analysis showed that the levels of Th17 cells in groups B and D before treatment were positively correlated with the CAT score (P < 0.05), which were negatively correlated with FEV₁ , FEV₁% Pred, FVC and FVC% Pred. The levels of Th17 cells were not correlated with the CAT score, FEV₁, FEV₁% Pred, FVC and FVC% Pred in groups A and C. The levels of Th17 cells after treatment were positively correlated with the CAT score, which were negatively correlated with FEV₁ , FEV₁% Pred, FVC and FVC% Pred (P < 0.05). CONCLUSION: The peripheral Th17 cell level has a good correlation with IL-17, IL-6, CAT score and pulmonary function in COPD patients, suggesting a potential value to predict the symptom severity and prognosis of COPD.     

Association of SOX5 polymorphisms in chronic obstructive pulmonary disease-related pulmonary hypertension

SOX5) gene single nucleotide polymorphisms (SNPs) among stable chronic obstructive pulmonary disease (COPD) patients,COPD with pulmonary hypertension (PH) patients and healthy controls,and to explore the association of the SOX5 SNPs in COPD-related PH.METHODS: From April 2013 to April 2015,250 patients with stable COPD were enrolled continuously in Ningxia People's Hospital according to COPD treatment guidelines (2013 edition).All the patients received echocardiography,and were divided into COPD with PH group[pulmonary artery systolic pressure (PASP)≥50 mmHg,n=103] and COPD without PH group (PASP<50 mmHg,n=147).The healthy persons (matched for age,sex,race and smoking index,n=127) were selected as control group at the same period.Genotyping of SOX5 gene rs10842262 and rs11046966 loci was performed using MassARRAY genotyping system (Sequenom).Genotype frequencies were calculated.RESULTS: Age,sex and smoking index showed no significantly difference between control group and COPD group,neither between COPD with PH group and COPD without PH group.Genotype frequencies of SOX5 gene rs10842262 and rs11046966 loci between control group and COPD group was of significant difference (P<0.05).Genotype frequencies of SOX5 gene rs10842262 and rs11046966 loci showed no significant difference between COPD with PH group and COPD without PH group.CONCLUSION: SOX5 gene rs10842262 and rs11046966 loci may play an important role in COPD,but not in COPD-related PH.     

Effects of N-acetylcysteine on Clara cells and CC16 in rat COPD model

AIM: To investigate the effects of N-acetylcysteine (NAC) on the number of Clara cells and secretion of Clara cells secretory protein (CC16) in rat chrohic obstructive pulmonary disesae (COPD) model.METHODS: Thirty rats were divided into control, COPD and NAC groups (n=10). The change of Clara cell ultrastructure was detected through transmission electron microscope. The number of Clara cells and synthesis of CC16 were measured by immunohistochemistry. The CC16 levels in bronchoalveolar lavage fluid (BALF) and serum were tested by ELISA. The level of CC16 mRNA in lung was determined by RT-PCR.RESULTS: The percentage of Clara cells in terminal bronchioles in the COPD group was significantly decreased than that in the control (P<0.01), and the percentage in NAC group was significantly higher than that in COPD group (P<0.01). The levels of CC16 in the BALF and serum in COPD group were significantly lower than those in control group (P<0.01, respectively), and the levels of CC16 in NAC group were significantly higher than those in COPD group (P<0.05, respectively). The expression of CC16 mRNA in COPD group was weaker than that in control group and NAC group (P<0.01, respectively).CONCLUSION: The number of Clara cells and the secretion of CC16 decrease in a rat model of COPD. Antioxidant NAC can enhance the synthesis and secretion of CC16, which may be a mechanism for the suppression of airway inflammation.     

Effect of cigarette smoking condensate on HDAC2 and inflammatory mediators in mouse myoblast C2C12 cells

AIM: To investigate the effect of cigarette smoking condensate on histone deacetylase 2 (HDAC2) and inflammatory mediators in mouse myoblast C2C12 cells. METHODS: C2C12 cells were treated with cigarette smoke extract (CSE). HDAC2 siRNA was transfected into the cells using Lipofectamine^TM 2000. The levels of interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α) in the culture supernatants were measured by ELISA, and the expression of HDAC2 at mRNA and protein levels was determined by real-time PCR and Western blotting. RESULTS: The expression of HDAC2 at mRNA and protein levels in CSE group was lower than that in control group (P<0.05). The supernatant levels of IL-8 and TNF-α in CSE group were significantly higher than those in control group (P<0.05). When the cells were transfected with HDAC2 siRNA followed by CSE stimulation, the expression of HDAC2 at mRNA and protein levels was decreased, and the supernatant levels of IL-8 and TNF-α were significantly increased as compared with CSE group and control group (P<0.05).CONCLUSION: Under the oxidative stress condition, C2C12 cells generate high levels of IL-8 and TNF-α by down-regulating the expression of HDAC2.     

Inhibitory effect of salidroside on liver oxidative stress in rats with non-alcoholic steatohepatitis

AIM：To explore the effects of salidroside (SDS) on the oxidative stress in liver tissues from rats with non-alcoholic steatohepatitis (NASH). METHODS：The experimental animal model of NASH was established in SD rats fed on high-fat and high-cholesterol diet (HFHCD) for 14 weeks. SDS (300 mg·kg-1·d-1) was administered via gavage daily from the 8th week after HFHCD feeding. At the end of the 14th week, serum samples were taken for detection of alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG) and total cholesterol (TC). Liver tissues were taken for TG, TC, malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) detection. The content of 8-isoprostaglandin F2α (8-iso-PGF2α) in liver tissues was determined by ELISA. The liver histopathological changes were observed under microscope with HE staining. The expression of 8-hydroxydeoxyguanosine (8-OHdG) in liver tissues was determined by immunohistochemical staining. RESULTS：At the end of the 14th week, ALT, AST, TG and TC in serum, and TG, TC, MDA and 8-iso-PGF2α in liver homogenate in NASH model group were significantly increased compared with control group, while SOD and GSH in liver tissues were significantly decreased. The liver expression of 8-OHdG in NASH model group was higher than that in control group. Compared with NASH model group, SDS significantly inhibited the elevation of serum ALT, AST, TG and TC, and liver TG, TC, MDA and 8-iso-PGF2α, but increased the levels of SOD and GSH in liver tissues. Meanwhile, the liver histopathological score and 8-OHdG expression were decreased in SDS treatment group. CONCLUSION：Salidroside can effectively inhibit steatohepatitis induced by HFHCD, and its antioxidant effect may be one of the mechanisms.     

Effects of astragaloside on the levels of sex hormone and oxidative stress injury in rats with polycystic ovary syndrome

AIM To investigate the effects of astragaloside on the levels of sex hormone and oxidative stress in rats with polycystic ovary syndrome （PCOS）. METHODS Female SD rats （n=60） were randomly divided into normal control group, model group, Diane-35 （0.339 2 mg/kg） group, low dose astragaloside （12.5 mg/kg） group and high dose astragaloside （50 mg/kg） group, with 12 rats in each group. The PCOS model was induced by letrozole （1 mg/kg）, which was administered by gavage once a day for 3 weeks. After administration, the estrus cycle of the rats was observed by vaginal smear, and the ovarian index was calculated. HE staining was used to observe the histopathological changes of the ovaries. Serum levels of the sex hormones testosterone （T）, estradiol （E₂）, luteinizing hormone （LH） and follicle-stimulating hormone （FSH） were measured by ELISA. The levels of superoxide dismutase （SOD）, malondialdehyde （MDA） and glutathione peroxidase （GSH-Px） in serum and ovarian tissue were detected by colorimetry, and the protein levels of steroidogenetic acute regulatory protein （StAR） and apoptosis-related proteins cleaved caspase-3, Bax and Bcl-2 in ovarian tissue were detected by Western blot. RESULT Compared with control group, the oestrous cycle of the rats in model group was disorder, and the ovarian index was increased, ovary was polycystic. The serum levels of T, LH and MDAwere significantly increased （P<0.05）, while the contents of E2, FSH and the activities of GSH-Px and SOD were significantly decreased （P<0.05）. The levels of MDA, StAR, cleaved caspase-3 and Bax proteins in ovarian tissue were significantly up-regulated （P<0.05）. GSH-Px and SOD activities and Bcl-2 protein levels were significantly down-regulated （P<0.05）. CONCLUSION Astragalosideeffectively balances the levels of sex hormone in PCOS rats and relieves the oxidative stress injury, the mechanism may be related to the inhibition of StAR expression.     

Effects of hesperidin on inflammatory cytokine levels in chronic bronchitic rats

AIM: To observe the effects of hesperidin on the inflammatory cytokine levels in chronic bronchitic rats.METHODS: The rats were randomly divided into control group, model group and hesperidin treatment group. The rat model of chronic bronchitis was established by smoking. The pathological changes of the bronchial and lung tissues were observed by HE staining. The levels of TNF-α, IL-6 and IL-10 in the bronchoalveolar lavage fluid were analyzed by ELISA. The protein expression levels of ICAM-1 and VCAM-1 were detected by Western blot.RESULTS: Compared with model group, hesperidin treatment significantly reduced inflammatory infiltration in the bronchial and lung tissues, improved the integrity of the alveolar structure, and decreased the levels of TNF-α and IL-6 in the bronchoalveolar lavage fluid, but had no effect on the IL-10 level. Moreover, the protein expression of ICAM-1 and VCAM-1 were dramatically inhibited after hesperidin treatment.CONCLUSION: Hesperidin decreases the levels of TNF-α and IL-6 in the bronchoalveolar lavage fluid in the rats with chronic bronchitis, which may be associated with the inhibition of ICAM-1 and VCAM-1 expression.     

Effect of insulin on early myocardial oxidative stress in severely burnt rats

AIM：To investigate the effect of insulin on early myocardial oxidative stress in severely burnt rats. METHODS：Twenty-four Sprague-Dawley rats were randomly divided into three groups (8 rats in each group): control group (sham scald group), scald injury group and scald injury + insulin group. The rats in the latter two groups were subject to third-degree burn with 30% total burn surface area (TBSA) on the back, and then received intraperitoneal injection of normal saline (40 mL/kg) immediately. The rats in scald injury + insulin group were subcutaneously injected with insulin (1 U/kg), while those in scald injury group received subcutaneous injection of the same volume of normal saline. All rats were sacrificed 24 h after scald, and blood samples from abdominal aorta and myocardial tissues were taken. Blood glucose (BG) content, blood lactate dehydrogenase (LDH) and creatine kinase (CK) activity, and myocardial oxidative and antioxidative indexes, including malondialdehyde (MDA), xanthine oxidase (XO), myeloperoxidase (MPO), superoxide dismutase (SOD), catalase (CAT) and glutathion peroxidase (GPx), were detected by spectrophotometry. RESULTS：(1) Compared with control group, BG levels in scald injury group and scald injury + insulin group were significantly elevated (P<0.05). But BG in scald injury + insulin group was significantly lower than that in scald injury group (P<0.05). (2) Compared with control group, the activity of LDH and CK in scald injury group was significantly increased (P<0.05), while that in scald injury + insulin group was significantly lower than that in scald injury group (P<0.05). (3) Compared with control group, the MDA content and the XOD and MPO activity in scald injury group were significantly increased (P<0.05), while the activity of SO, CAT and GPx was significantly decreased (P<0.05). Compared with scald injury group, the MDA content and the XO and MPO activity in scald injury + insulin group were significantly reduced (P<0.05), while the activity of SOD, CAT and GPx was significantly elevated (P<0.05). CONCLUSION：Insulin intervention attenuates early myocardial oxidative stress in burnt rats and decreases the rise in myocardial enzyme activity, thus exerting a cardioprotective effect.     

Role of oxidative stress in gastric motility of diabetic rats

AIM: To investigate the changes of oxidative stress in the stomach tissues and their roles in gastric motility and interstitial cells of Cajal (ICC) in diabetic rats. METHODS: Thirty-eight SD rats (8-week-old, male) were intraperitoneally injected with streptozotocin (STZ). Diabetes was successfully induced in 36 of them. The diabetes rats were randomly divided into untreated diabetes group and treated diabetes group. Eighteen healthy SD rats (8-week-old, male) served as controls. The body weight and the levels of blood glucose and glycosylated hemoglobin were measured. At the end of week 1 and week 10, 9 rats were sacrificed in each group. The gastric emptying rate and the levels of malondialdehyde (MDA),superoxide dismutase (SOD), tumor necrosis factor α (TNF-α), tyrosine kinase receptor c-Kit and stem cell factor (SCF) in gastric smooth muscle were analyzed. The apoptosis of ICC in gastric tissues was detected by the methods of immunocytochemistry and TUNEL. RESULTS: Compared with control group, gastric motility and SOD activity in untreated diabetes group were significantly weakened, the levels of MDA and TNF-α increased, the levels of c-Kit and SCF decreased, and apoptosis of ICC enhanced. In treated diabetes group, the oxidative stress level was attenuated, antioxidant capacity was enhanced, the levels of c-Kit and SCF were significantly increased, and the ICC apoptosis was reduced. Gastric motility was significantly improved after antioxidant therapy. CONCLUSION: Hyperglycemia affects the expression of antioxidant enzymes in the stomachs of diabetic rats. Oxidative stress is caused by hyperglycemia and is an important factor in the etiology of gastric motility dysfunction in diabetic rats, which may be correlated with the augmentation of ICC apoptosis resulting from oxidative stress-induced c-Kit/SCF damage.     

Effects of oxidative stress and inflammatory response on kidney injury in mice with hyperthyroidism

AIM To explore the effects of oxidative stress and inflammatory response on kidney injury induced by hyperthyroidism in mice. METHODS Forty male Kunming mice were randomly divided into control group （n=20） and L-thyroxine （T4） group （n=20）. The mice in T4 group were intraperitoneally injected with T4 diluent at a dose of 1 mg/kg to induce hyperthyroidism, and those in control group were injected with normal saline of the same volume. After 7 weeks, the mice were weighed and dissected, the kidneys were removed and weighed, and the length of tibia was also measured. The activity of superoxide dismutase （SOD） and the content of malondialdehyde （MDA） in the kidney tissues were detected. The pathological changes of the kidney tissues were observed by HE staining. The levels of 4-hydroxynonenal （4-HNE）-modified proteins, interleukin-1 receptor-associated kinase 1 （IRAK1） and tumor necrosis factor receptor-related factor 6 （TRAF6） were determined by Western blot and immunohistochemistry. RESULTS Compared with control group, the body weight of the mice was decreased, while the kidney size and weight were increased significantly in T4 group. In addition, the ratios of kidney weight/body weight and kidney weight/tibia length were also increased （P<0.05）. In T4 group, the renal tubules were enlarged, and the epithelial cells of renal tubules were swollen and exfoliated, with vacuolar degeneration. Furthermore, reduced SOD activity, and increased MDA content and 4-HNE-modified proteins were found in T4 group, all of which were related to oxidative stress （P<0.05）. The levels of inflammation-related proteins IRAK1 and TRAF6 were significantly increased in T4 group （P<0.05）. CONCLUSION Excessive T4 may lead to kidney hypertrophy and injury in mice, and the mechanism may be related to oxidative stress and inflammatory response.     

Effects of oxidative stress on high-fat,high-salt diet and sucrose solution-induced metabolic syndrome in nephropathy rats

AIM: To establish a suitable animal model of nephropathy associated with metabolic syndrome (MS) induced by abnormal diet, and to investigate the effects of oxidative stress on renal damage in MS rats. METHODS: Normal 7-week-old male SD rats were randomly divided into 2 groups.The animals were fed with normal chow (control group, n=10) or high-fat and high-salt diet plus 20% sucrose solution (MS model group, n=10) for 20 weeks. Systolic blood pressure (SBP) was measured monthly. The levels of blood glucose, serum and urinary creatinine (Cr), total cholesterol (TC), triglycerides (TG), fasting insulin (FIns), urinary protein, urinary albumin and urinary sodium were determined. Insulin resistance (HOMA-IR), creatinine clearance (Ccr), urinary protein excretion (UPE), urinary albumin excretion (UAE) and urinary sodium excretion (USE) were calculated. Renal total-antioxidant capacity (T-AOC), inhibiting superoxide anion capacity (ISAC), malondialdehyde (MDA) content, and antioxidant enzyme activity were measured. Renal protein expression of Cu/Zn-SOD, NADPH oxidase subunit p47^phox and p22^phox was detected by Western blotting. In addition, pathological changes of the kidney were observed with PAS and Masson staining,and degree of glomerulosclerosis (GS) and tubulointerstitial injury was evaluated. RESULTS: Compared with control rats, SBP, TC, TG, FIns, USE and UAE were increased in MS rats. Furthermore, the MS rats showed a significant elevation of renal MDA content, p47^phox protein expression and GS score, and reduction of T-AOC, ISAC, SOD activity, and Cu/Zn-SOD protein expression in the kidney. CONCLUSION: SD rats fed with abnormal diet produce a suitable animal model of MS nephropathy that mimics the major features of human MS. Oxidative stress caused by up-regulation of NADPH oxidase expression and down-regulation of SOD expression may be one of the mechanisms leading to MS renal damage.     

Establishment of chronic obstructive pulmonary disease rat models by passive cigarette smoking and intratracheal instillation of lipopolysaccharide

AIM:To establish rat chronic obstructive pulmonary disease(COPD) models by passive cigarette smoking plus intratracheal instillation of lipopolysacchride(LPS) or passive cigarette smoking only, which would be similar to the pathogenesis of human COPD. METHODS:48 Wistar rats were randomly divided into 4 groups.(1) Healthy control I group(n=12), rats were bred 4 weeks;healthy control II group(n=12), rats were bred for 3months. (2) Model group I (n=12), 200μg lipopolysaccharide(LPS) was instilled intratracheally once for every two weeks and the rats were exposured to 5% of cigarette smoke, 0.5 h/d for 4 weeks.(3) Model group II(n=12),rats were exposed to 5% of cigarette smoke, 0.5 h/d for 3 months. The pathologic changes of airways and lung tissues, pulmonary function and blood gas analysis were determined. The airway wall lymphocytes and alveolar macrophages were counted. The cross areas of epithelial layer, smooth muscle layer and lamina propria of bronchi were measured. The hydroxyproline of lung tissue homogenates was determined by biochemistry method.RESULTS:The pathologic changes of airways and lung tissue of two models were similar to but milder than those of COPD patients(biopsy data). The collagen deposition and the cross areas of epithelial layer and smooth muscle layer in airway walls of two model groups were significantly increased than those of control groups(P＜0.01,P＜0.05).FEV_0.3/FVC% of two model groups, PaO₂ and SaO₂ of model I group were significantly decreased, while R_i and R_e in model I group were significantly increased than that of control I group(P＜0.05). The PaCO₂ and the counts of lymphocytes and alveolar macrophages of both model groups were significantly increased than those of the control groups (P＜0.01). Lots of alveolar macrophages had phagocyted smoke granules. The amounts of hydroxyproline of two model groups were significantly increased than those of control group((P＜0.05) and were negatively related to the FEV_0.3/FVC%, respectively (P＜0.01,P＜0.01) and positively related to airway resistance of model I group(P＜0.01). CONCLUSIONS:COPD rat models were successfully established by passive cigarette smoking plus intratracheal instillation of LPS and cigarette smoking only. The pathologic changes were similar but milder than those of COPD patients. The airway obstruction of model I group was more severe than that of model II group, but they have no significant difference.