Effect of hyperbaric oxygen on periodontitis with psychological stress in rats

AIM: To investigate the role of chronic psychological stress on periodontitis and the effects of hyperbaric oxygen (HBO) on periodontitis with psychological stress in rats. METHODS: Male special pathogen-free Wistar rats (n=80) were randomly divided into 4 groups: (1)normal control group; (2)experimental periodontitis group: the periodontitis model was induced by wrapping 3/0 silk ligature inoculated with Porphyromonas gingivalis around the left maxillary second molar of the rats; (3)psychological stress stimulation group; (4)periodontitis model with stress stimulation group. Psychological stress was removed at the 9th week after ligature, and 4 rats from each experimental group were randomly chosen for HBO treatment. The rats were sacrificed at the 2nd, 4th, 8th and 10th weeks after ligature. The levels of blood glucose, adrenocorticotropic hormone (ACTH), corticosterone and adrenaline were measured as the stress markers. The histological changes of periodontal tissues were observed under microscope with HE staining. RESULTS: The levels of blood glucose, ACTH, corticosterone and adrenaline in psychological stress stimulation group and periodontitis with stress group were significantly higher than those in control group and experimental periodontitis group at the 2nd and 4th weeks after ligature (P<0.05). The levels of the stress markers were significantly lower than those in untreated groups in the 10th week after HBO (P<0.01). The sites of gingival attachment were normal in control group and psychological stress stimulation group. Periodontal pocket, and periodontal attachment loss (AL) were observed in experimental periodontitis group. The tissue damage was much heavier in periodontitis model with stress stimulation group as the furcation of tooth was exposed and the tissue damage was observed on both sides of the adjacent teeth. No significant difference of AL between psychological stress stimulation group and normal control group during the experiment was observed. The AL in periodontal model with stress stimulating group was significantly higher than that in experimental periodontitis group at the 2nd, 4th and 8th weeks (P<0.01). The level of AL was attenuated at the 10th week after HBO (P<0.01). No difference of histological change in periodontal tissues was observed between control group and psychological stress stimulation group. Severer inflammatory changes and alveolar bone destruction were observed in periodontitis with stress group than those in experimental periodontitis group. The levels of inflammation reduced at the 10th week after HBO. CONCLUSION: Stress stimulation is one of the inducing factors of periodontitis in rats, which aggravates periodontitis. HBO may represent a useful way in treating psychological stress periodontitis.     

Effect of hyperbaric oxygen on HIF-1α expression in rat experimental periodontitis with psychological stress

AIM: To investigate the effect of hyperbaric oxygen (HBO) on hypoxia-inducible factor-1α (HIF-1α) expression in rat experimental periodontitis with psychological stress. METHODS: Male special pathogen-free Wistar rats (n=120) were randomly divided into 4 groups: normal control group; psychological stress stimulation group; experimental periodontitis group: the periodontitis model was induced by wrapping 3/0 silk ligature inoculated with Porphyromonas gingivalis around the left maxillary second molar of the rats; periodontitis model with stress stimulation group. Psychological stress was removed at the 9th weeks after ligature, 6 rats from each experiment group were randomly chosen to HBO treatment. The rats were sacrificed at the 2nd, 4th, 8th and 10th weeks after ligature. Gingival index (GI) and attachment loss (AL) were measured before sacrifice. The histological changes of periodontal tissues were observed under microscope with HE staining. The expression of HIF-1α was observed by the method of immunohistochemistry. RESULTS: The sites of gingival attachment were normal in control group and psychological stress stimulation group. Periodontal pocket, and periodontal attachment loss were observed in experimental periodontitis group. The tissue damage was much serious in periodontitis model with stress stimulation group. No significant difference of GI and AL among psychological stress stimulation group and normal control group during the experiment was observed. GI and AL in periodonitis model with stress stimulating group were significantly higher than those in experimental periodontitis group at the 4th and 8th weeks (P < 0.01). The levels of GI and AL were significantly lower at the 10th weeks after HBO treatmnt than those in untreated groups (P < 0.05). No significant difference of HIF-1α expression scores among psychological stress stimulation group and normal control group was found. HIF-1α expression scores in periodonitis model with stress stimulating group was significantly higher than that in experimental periodontitis group at the 4th and 8th weeks (P < 0.01). At the 10th weeks after HBO treatment the levels of HIF-1α were significantly lower than that in untreated groups (P < 0.01). CONCLUSION: Stress stimulation may aggravate periodontitis by decreasing tissue oxygenation in rats. HBO may represent a useful way in psychological stress periodontitis therapy.     

Effect of psychological stress on development of periodontitis and expression of periodontal hypoxia-inducible factor 1α in rats

AIM: To investigate the effect of psychological stress on the development of periodontitis and the expression of periodontal hypoxia-inducible factor 1α(HIF-1α) in rats.METHODS: Forty-eight male Wistar rats(SPF grade) were randomly divided into 4 groups:(1) normal control group, i.e. naive rats;(2) experimental periodontitis group: the periodontitis model was induced by wrapping 3-0 silk ligature inoculated with putative periodontopathic bacteria around the left maxillary second molar of the rats;(3) stress group: the rats were treated with stress alone;(4) periodontits with stress group, the periodontitis model was induced as above,and the rats were treated with stress. The rats were sacrificed at week 1, 4, 6 and 8 after the ligature. The attachment losses(AL) were measured by home-made probe. The histological changes of periodontal tissues stained with hematoxylin and eosin(HE) were observed under microscope. The HIF-1α expression level in the periodontal epithelium was determined by immunohistochemistry that was used to evaluate the severity of hypoxia by measuring the average rate of HIF-1α-positive cells.RESULTS: No significant difference of AL between stress group and normal control group was observed(P>0.05).The AL and the average rate of HIF-1α-positive cells in periodontitis with stress group were significantly higher than those in experimental periodontitis group at time points of week 4,6 and 8 after ligature(both P<0.01).CONCLUSION: Psychological stress is one of the periodontitis inducing factors in the animal model. Psychological stress may aggravate periodontitis by decreasing tissue oxygenation in rats.     

Effects of baicalin on serum levels of IL-6 and IL-4 in mouse periodontitis

AIM: To investigate the effect of baicalin on experimental periodontitis in mouse model by comparing the histological changes in periodontal tissues and serum levels of inter leukin(IL)-6/IL-4 in mice, and to analyze the role of baicalin in immune regulation and anti-inflammatory mechanisms. METHODS: Twenty-seven male Kunming mice (SPF grade, 12-week-old) were randomly divided into 3 groups. The naive mice were used in normal control group. In experimental periodontitis group, the periodontitis model was produced by ligature of braided silk around the first maxillary molar and inoculation with putative periodontopathic bacteria. Five weeks after the ligature, the mice were fed with 10% glucose, and gavaged with distilled water. In baicalin treatment+periodontitis group, the periodontitis model was induced as above, then gavaged with baicalin at the beginning of the fifth week after the ligature. The mice were sacrificed at week 4, 6 and 8. The histological changes of the periodontal tissues were observed under microscope with hematoxylin and eosin (HE) staining. The serum level of IL-6 and IL-4 in the mice were determined by ELISA. RESULTS: The periodontal tissues showed moderate inflammatory damages in experimental periodontitis group. The periodontal destruction was significantly reduced in baicalin treatment+periodontitis group. The serum level of IL-6 in experimental periodontitis group was significantly higher than that in control group and baicalin treatment+periodontitis group (P<0.01), and the serum level of IL-6 in baicalin treatment+periodontitis group was significantly lower than that in periodontitis group at week 6 and 8 (P<0.01). The serum level of IL-4 in periodontitis group was significantly lower than that in control and baicalin treatment+periodontitis group (P<0.01). The serum level of IL-4 in baicalin treatment+periodontitis group was significantly higher than that in periodontitis group at weeks 6 and 8 (P<0.01).CONCLUSION: The pathogenesis of periodontitis is closely related to the imbalance of Th1/Th2 cytokines, characterized by increased serum level of IL-6 and the decreased serum level of IL-4. Baicalin plays a significant role in treating mouse periodontitis by decreasing the serum level of IL-6 and increasing the serum level of IL-4.     

Role of interleukin-4 in the development of periodontitis in mouse model

AIM: The purpose of this study was to investigate the role of interleukin-4 (IL-4) in the development of periodontitis in mice by low dosage of Trichinella spiralis (T. spiralis) infection.METHODS: Twenty-seven male Kunming mice in specific pathogen free grade were randomly divided into three groups: (1) the normal control group; (2) the experimental periodontitis group, which was produced by ligature of braided silk around the first maxillary molar, and was inoculated with putative periodontopathic bacteria; (3) the periodontitis with T. spiralis infection group. The mice were sacrificed at the end of 1, 3 and 5 weeks. The probing depth (PD) was measured before the mice were euthanized. The histological change of periodontal tissues was observed under the microscope after the samples were stained with hematoxylin and eosin. Furthermore, the serum level of IL-4 was determined by ELISA. RESULTS: (1) The serum level of IL-4 in T. spiralis-infected group was significantly higher than that in experimental periodontitis group (P<0.01). (2) The PD in T. spiralis-infected group was significantly lower than that in experimental periodontitis group (P<0.01). (3) Only a mild inflammatory response was observed in T. spiralis-infected animals. CONCLUSION: T. spiralis infection upregulates IL-4 expression and attenuates periodontitis in mice.     

Effect of nimesulide on ligature-induced periodontitis in rats

AIM: The purpose of this study was to observe the effect of nimesulide on periodontitis. METHODS: The gingival index (GI) was measured before the rats were sacrificed at the ends of week 4, 5 and 8. The periodontal tissues were stained with hematoxylin and eosin. Histological changes were observed by microscope. The periodontal attachment loss (AL) was measured by Tiger cell image analyzer. RESULTS: (1) Experimental periodontitis was successfully induced in rats by placing a piece of 3/0 braided silk around the cervix of the lower incisors at week 4 after the ligature. (2) In ligature-induced periodontitis group, at week 4 after the ligature, the GI and AL were significantly higher than those in control group (P<0.01). The histopathologic changes of periodontium in periodontitis group showed obvious inflammation, and the severity of destruction for periodontium was increased as time passed. (3) In the nimesulide prevention group, the GI and AL were significantly lower than those in periodontitis group (P<0.01). The histopathologic examination showed less inflammatory responses, and no obvious alveolar bone resorption was observed. (4) In the nimesulide treatment group, the GI and AL were significantly lower than those in periodontitis group at the end of week 5 and 8 after the ligature (P<0.01).CONCLUSION: (1) In ligature-induced periodontitis, nimesulide inhibits effectively its progress. (2) In the developing periodontitis, a significant improvement is observed in GI and AL following the treatment with nimesulide.     

Change of nitric oxide concentration in ligature-induced periodontitis in rats

AIM: To study the possible role of nitric oxide (NO) in the development of periodontitis and the relationship between the NO concentration and the attachment loss. METHODS: Seventy-two Sprague-Dawley rats were randomly assigned to two groups, the control group and periodontitis group. Experimental periodontitis in rats was produced by a ligature of braided silk. The nitric oxide concentration was indirectly ascertained by the concentration of nitrite (NO2-) and nitrate (NO3-) in the gingival tissue, which was assayed by spectrophotometry. The attachment loss (AL) was measured by the technology of the cellular graphics engineering research. The histopathologic change in periodontium was observed under a light microscope by using the histotomy. RESULTS: Compared to control group, the NO2-/NO3- concentration in gingival tissue was significantly higher in periodontitis group at four weeks and eight weeks following ligation (P<0.01). In periodontitis group, the NO2-/NO3- concentration in gingival tissue was higher at eight weeks than that at four weeks following ligation (P<0.01). At four weeks and eight weeks, the AL in experimental periodontitis in rats was significantly increased than that at one week after ligation (P<0.01); and the AL was also much higher at eight weeks than that at four weeks (P<0.01). CONCLUSIONS: The NO2-/NO3- concentration in the gingival tissue in periodontitis group was significantly higher than that in control group. These results demonstrate that the NO2-/NO3- concentration is related to the severity of AL, and NO synthesis is very important to the process of inflammation and lesion in periodontium. Reducing NO production may be of great therapeutic value in the treatment of periodontitis.     

The inhibitory effect of aminoguanidine on periodontitis in rats

AIM: To study the inhibitory effect of aminoguanidine(AG) on periodontitis. METHODS: Experimental periodontitis was produced in rats by a ligature of braided silk, the NO concentration was assayed by spectrophototometry, the attachment loss of periodontium was measured by using technology for image and graphics engineering research and the histopathologic changes of periodontium were also examined under a light microscope. RESULTS: The NO concentration significantly decreased after AG treatment for 4 weeks, and the inflammation and the damages of periodontium was also reduced significantly. CONCLUSION: The inhibition of iNOS by AG may be a potential therapeutic strategy for the treatment of periodontitis.     

LBP regulates PI3K/Akt/eNOS signaling pathways in ovariectomized rat myocardium to exert antioxidative effect

AIM: To observe the influence of Lycium barbarum polysaccharide (LBP) on the PI3K/Akt/eNOS signaling pathways in ovariectomized rat myocardium. METHODS: Female SD rats (n=30) were divided into sham operation group, ovariectomized group, progynova group, high-dose LBP group and low-dose LBP group. The serum levels of estradiol, lactate dehydrogenase (LDH) and creatine kinase (CK) were measured by ELISA. The myocardial contents of H₂S and oxidative stress injury-related indicators were also detected. The morphological changes of the myocardium were observed with HE staining. The expression of eNOS and PI3K/Akt pathway-related proteins in the myocardium was determined by Western blot. RESULTS: Compared with sham operation group, the serum level of estradiol, the content of H₂S, the activity of GSH-Px, and the expression of eNOS and PI3K/Akt pathway-related proteins in the myocardium in ovariectomized group were all decreased, and the levels of ROS and MDA in the myocardium were increased (P<0.05). The serum levels of LDH and CK were also increased. The arrangement of the myocardial cells was disordered, and the intercellular space was also increased in the ovariectomized group. Compared with ovariectomized group, the serum level of estradiol, the myocardial levels of H₂S and GSH-Px, and the protein levels of eNOS and phosphorylated Akt were all increased in high dose group, while the levels of ROS and MDA in the myocardium were decreased (P<0.05). The serum levels of LDH and CK were also decreased. The morphological changes of the rat myocardium were improved in high dose group. CONCLUSION: LBP prevents and treats postmenopausal cardiovascular lesions through regulating PI3K/Akt/eNOS signaling pathways in ovariectomized rats.     

Effects of icariin on expression of transforming growth factor β1 and type Ⅳ collagen in diabetic rat testis

AIM: To determine the beneficial effects of icariin on streptozotocin (STZ)-induced diabetic testopathy in rats. METHODS: The diabetic animal model was induced in male Sprague-Dawley rats by an injection of streptozotocin (40 mg/kg, iv). The rats were randomly divided into 3 groups: control group, model group and icariin (80 mg/kg, ig) group. Twelve weeks after injected with streptozotocin, all rats were anaesthetized and killed to remove the testes from scrotum. Serum concentrations of glucose and testosterone, and the levels of succinate dehydrogenase (SDH), acid phosphatase (ACP), γ-glutamyl transpeptidase (γ-GT) and lactate dehydrogenase (LDH) in testes were measured. The morphology of the testicular tissues was observed under light microscope. Immunohistochemistry was employed to determine the protein levels of TGF-β₁ and type Ⅳ collagen. RESULTS: Compared with control group, the content of serum glucose increased while the serum level of testosterone and the activitiy of SDH, ACP, γ-GT and LDH in testis decreased in model group (P<0.01). The histopathological examination showed that the diameters of seminiferous tubules and various grades of spermatocytes in the testis were markedly decreased. Compared with control group, the expression of TGF-β₁ and collagen Ⅳ was significantly increased in model group. These alterations were significantly attenuated in icariin group (P<0.01). CONCLUSION: Icariin evidently relieves testicular damage in rats with diabetic testopathy by improving the secretion of testosterone and reducing the expression of TGF-β₁ and collagen Ⅳ at protein level.     

Limb ischemic preconditioning protects human umbilical vein endothelial cells from oxidative stress induced by H2O2

AIM: To investigate the effects of the sera from the rats after limb ischemic preconditioning (LIPC) on human umbilical vein endothelial cells (HUVECs) injured by hydrogen peroxide (H₂O₂). METHODS: The HUVECs were divided into 5 groups: the cells in control group were cultured without any intervention; the cells in model group (M) were damaged by 1 mmol/L H₂O₂ for 2 h; the cells in early preconditioning serum (EPS) group, delayed preconditioning serum (DPS) group or sham limb ischemic preconditioning serum (SPS) group were treated with the corresponding serum at 5% for 12 h, respectively, and then treaed with H₂O₂ for 2 h. The viability of the HUVECs was analyzed by flow cytometry. The lactate dehydrogenase (LDH) in the culture media was detected. The cell adhesion molecules in the HUVECs were detected by real-time PCR. The mRNA and protein expression of heme oxygenase-1 (HO-1) was also determined. RESULTS: The viability of HUVECs incubated with 1 mmol/L H₂O₂ for 2 h significantly decreased compared with the control cells, which was accompanied with the augmentations of LDH in the medium and the cell adhesion molecules in cells, such as vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1). Preincubation with EPS and DPS derived from the rats subjected LIPC attenuated these injuries. Furthermore, pretreatment with EPS and DPS increased the expression of HO-1 at mRNA and protein levels. CONCLUSION: LIPC protects the HUVECs from H₂O₂-induced injury.     

Experimental study on preventing obesity by compound rhubarb preparation in rats

AIM: To investigate the effect of compound rhubarb preparation (Kintop) in preventing obesity in rats and its probable mechanism involved. METHODS:Twenty-six newborn SD rats were randomly grouped as rhubarb preparation plus high-energy forage group(n=8), high-energy forage control group(n=8) and ordinary forage control group(n=10). The rats in rhubarb preparation plus high-energy forage group and high-energy forage control group were fed with high-energy forage and those in ordinary forage control group were fed with ordinary forage. The rats in rhubarb preparation plus high-energy forage group were administered by compound rhubarb preparation (40 mg·100 g^-1 body weight·d^-1) from 9th to 17th week. The dynamic changes in body weight, celiac fat weight and adipocytes size were measured. Immunohistochemical analysis of leptin in celiac adipocytes (ABC method) and measurement of serum leptin level (RID method) were performed. RESULTS:The body weight and the wet weights of celiac fat were lower, their adipocytes were smaller and immunohistochemical stainings of leptin were weaker in rhubarb preparation plus high-energy forage group than those in high-energy forage control group. There was an obvious positive correlation between the expression of leptin and celiac fat tissue weight(r=0.8663, P＜0.05). But the changes in serum leptin were not significant between groups. CONCLUSION:Compound rhubarb preparation (40 mg·100 g^-1 body weight·d^-1) can prevent the obesity in rats fed with high-energy forage. The mechanism might involve the decrease in adipocyte leptin expression.     

Effects of voluntary wheel running exercise on depressive-like behavior and circadian rhythmic alterations of neuroendocrine induced by chronic unpredictable mild stress in rats

AIM: To investigate the effect of 8-week middle intensity voluntary wheeling exercise on the depressive-like behavior and the circadian rhythmic alterations of plasma hormone and peptide induced by chronic unpredictable mild stress (CUMS) in rats. METHODS: Male Sprague-Dawley rats (n=90) were randomly divided into model group, model+exercise group and control group. Rats in model+exercise group received 8-week voluntary wheel running exercise plus CUMS procedure during the last 3 weeks at the same time. Exploratory locomotor activity was assessed by open field test, the anxiety-like behavior was measured by elevated plus-maze test, and lack of pleasure was detected by sucrose preference test. Blood samples were collected at each of 6 time points (ZT1, 5, 9, 13, 17 and 21 on the 2nd day after behavior testing). Plasma concentrations of corticosterone (CORT), melatonin (MT) and vasoactive intestinal peptide (VIP) were detected by ELISA. The plasma concentration of adrenocorticotropic hormone (ACTH) was measured by radioimmunoassay. The circadian rhythm changes of serum CORT, MT, VIP and ACTH concentrations in each group were compared by cosinor analysis. RESULTS: Compared with control group, locomotor activity, weight gain and sucrose consumption in model group were significantly reduced (P<0.01). The values of the percentage of open-arm time (OT%) and open arm entries (OE%) were obviously lower in model group than those in control group (P<0.01). Eight-week voluntary wheel running exercise may improve the above depression behavior caused by CUMS. The rats in model group showed an obvious disorder in circadian rhythm of plasma ACTH and CORT, including phase advance and decrease in amplitude. There also showed a markedly blunted circadian rhythm and decreased level of plasma MT in model rats compared to control rats. VIP expression was significantly higher than that in control group with 24 h rhythm, but the amplitude was significantly lower than that in control group, peak phase also delayed for 6 h. Eight-week exercise significantly ameliorated the abnormal expression and the disturbance secretion rhythm of ACTH, CORT, MT and VIP in plasma. CONCLUSION: Eight-week voluntary wheeling exercise ameliorates CUMS-induced depressive-like behaviors probably by rescuing the disturbed circadian rhythms and abnormal secretion of these neuroendocrine factors.     

Effect of oleanolic acid on expression of TNF-α and collagen in silicotic rats in vivo

AIM: To observe the effect of oleanolic acid (OA) on the expression of Tumor necrosis factor-α (TNF-α) and collagen in silicotic rats in vivo and its possible mechanism. METHODS: Male Wistar rats were divided into 4 groups according to the randomized block design: control group, model group, OA group and solvent control group (20 rats in each group). Except control group, the rats in other groups were induced by intratracheal instillation of silicon di-oxide (SiO₂; 250 mg/kg). The rats in OA group were intragastrically administered with OA (60 mg/kg) from the second day of giving SiO₂. The rats in solvent control group were gavaged daily with 0.6% sodium carboxymethyl cellulose solution (10 mL/kg). The rats in control group were given normal saline under the same condition for 56 consecutive days. All rats were killed at the 7th, 14th, 28th and 56th days. The lung coefficient was detected and the morphological changes were observed. The serum contents of TNF-α were detected by ELISA. The content of total collagen in the lung tissue was measured. The protein level of nuclear factor-κB (NF-κB) in the lung tissue was determined by immunohistochemical method. RESULTS: (1) According to the morphological changes, the silicosis model was successfully established. Compared with control group, the lung coefficient and total collagen increased obviously in model group and solvent control group. The lung coefficient and total collagen content in OA group at each time point reduced compared with those in model group and solvent group, and increased compared with those in control group at the corresponding time points. (2) The serum contents of TNF-α in model group and solvent control group significantly increased, peaking at the 14th day, slightly decreasing afterward, and showing statistically significant difference at each time point compared with those in control group. No significant difference between model group and solvent group at different time points was observed. OA had inhibitory effect on the contents of TNF-α compared with model group and solvent group at the corresponding time points. (3) NF-κB in model group and solvent control group significantly increased, peaking at the 28th day, and showing statistically significant difference at each time point compared with those in control group. The NF-κB expression in OA group was similar to model group, but significantly decreased compared with control group at each time point. CONCLUSION: OA inhibits the expression of TNF-α and collagen and attenuates the silicosis fibrosis, which may be related to the NF-κB pathway.     

Correlation between fecal metabolites and body weight/food intake in rats after chronic immobilization stress

AIM:To explore the correlation between fecal metabolites and body weight/food intake in rats after chronic immobilization stress (CIS). METHODS:Healthy male Sprague-Dawley (SD) rats (n=48) were randomly divided into control group and CIS group. The rats in CIS group were subjected to 3 h of immobilization stress a day for 21 consecutive days, and the rats in control group were kept for 21 d without stress intervention. The behaviors in open-field test (OFT) and elevated plus-maze test (EPM test), the sucrose consumption, the serum D-xylose content, and the small bowel transit rate were detected. The fecal metabolites were determined by ¹H-nuclear magnetic resonance spectroscopy (¹H-NMR) technique, and differential metabolites in the rats of 2 groups were analyzed by multivariate statistics. The correlation between body weight/food intake and above indexes of CIS rats were observed by Pearson correlation analysis. RESULTS:Compared with the control rats, the body weight of CIS rats was increased slowly and the food intake was decreased significantly (P<0.01). In the OFT, both the total and central distance covered in CIS rats were reduced significantly than those in control group within 5 min (P<0.01). In the EPM test, the residence time in open-arms of CIS rats within 5 min was shortened dramatically than those in the control group (P<0.01). The content of serum D-xylose and the sucrose consumption of the rats after stress for 21 d were decreased markedly (P<0.05). The small bowel transit rate of CIS rats was lower than that of control rats, but no statistical difference was observed (P>0.05). Acetate, butyrate, glucose, propionate, glutamate, ribose, pimelate, lactate, alanine, valerate, total 10 kinds of differential metabolites in fecal samples were detected, and the 10 kinds of metabolites in CIS rats were higher than that of the control rats (P<0.05). Pearson correlation analysis showed that food intake of CIS rats was negatively correlated with metabolites of acetate and pimelate (P<0.05), and no correlation between body weight and above indexes was found. CONCLUSION:Under the CIS condition, there are certain correlations between food intake and metabolites of acetate and pimelate, but the mechanism still need further study.     

Effects of imidapril on blood gas,oxidative stress and inflammatory factors in rats with acute lung injury induced by ammonium chloride

AIM: In this study, the rat lung injury model was induced by ammonium chloride for studying the effect of imidapril on blood gas, serum TNF-α, IL-6 and MDA concentrations, and AngⅡ and CD54 protein expression in rat lung tissue. METHODS: Male rats were randomly divided into 3 groups: control group, lung injury model group and drug group. The rats in control group were given saline (2 mL/kg), while the rats in lung injury model group were given 6% ammonium chloride (2 mL/kg). In drug group, imidapril (3 mg·kg^-1·d^-1) was given to the rats once daily for 1 week by intragastric gavage after given 6% ammonium chloride. On the 7th day, the rats were anesthetized with 2% so-dium pentobarbital. Abdominal aorta blood, venous blood and lung tissue were collected. The blood gas indexes and serum TNF-α, IL-6 and MDA concentrations were determined. The lung tissues were fixed and sliced, and the expression of AngⅡ and CD54 proteins was detected by immunohistochemistry. RESULTS: The PaCO₂ increased in lung injury model group compared with control group and drug group (P < 0.05).The expression of AngⅡ and CD54, and the concentrations of TNF-α, IL-6 and MDA also increased significantly (P < 0.01) in model group. Pulmonary edema, inflammation, alveolus congestion, hemorrhage and hyperplasia in model group were obvious compared with control group and drug group. CONCLUSION: Imidapril improves blood gas indexes, and reduces lipid peroxidation and inflammatory responses in the rats with lung injury induced by ammonium chloride.     

Effects of FK506 on anti-glomerular basement membrane nephritis in rats

AIM:To investigate the effects of FK506 on anti-glomerular basement membrane(GBM) nephritis in rats. METHODS: Anti-GBM nephritis model was elaborated by rabbit anti-rat GBM antibody injection in SD rats in this study. The rats were divided into three groups: FK506 treated group(0.5 mg·kg^-1·d^-1, sc), untreated nephritis control group and normal control group. FK506 was administered daily six hours after injection of anti-GBM IgG. All the rats were observed urinary protein at the 4th day, the 14th day and the 21st day. At the same time, the kidney specimens were collected, and T cell transforming function was also monitored.RESULTS:Rats injected with rabbit anti-GBM Ab developed heavy proteinuria by 4 days, and serum creatinine and serum urea appeared which kept on the rising. Glmerular hypercellularity, crescents, and protein casts were observed in nephritic rats. By electron microscopy, the thickening of GBM and loss of foot processes were seen. T cell transforming function was higher than normal. But, all pathological changes obviously turned for the better in FK506 treated group. CONCLUSION:FK506 could inhibit the progression of rat anti-GBM nephritis.     

Activity of H+-K+-ATPase in gastric parietal cells under stress in rats and analysis of electron microscopic enzyme cytochemistry

AIM: To demonstrate the changes of activity and electron microscopic enzyme cytochemistry staining of H⁺-K⁺-ATPase of gastric parietal cells under stress in rats. METHODS: Twenty-four male SD rats were randomly divided into normal group, stress group and stress+omeprazole (OM) group. Water immersion-restraint stress (WRS) model in SD rats was performed. The ulcer index (UI) of gastric mucosa and H⁺-K⁺-ATPase activity of gastric parietal cells were measured. The changes of ultrastructure and electron microscopic enzyme cytochemistry staining of parietal cells were observed under transmission electron microscope (TEM). RESULTS: Compared with control group, the UI of gastric mucosa and H⁺-K⁺-ATPase activity of gastric parietal cells increased (P<0.01 and P<0.05) in stress group. In stress+OM group, both UI and H⁺-K⁺-ATPase activity decreased (P<0.01) compared with stress group. Parietal cells were in a resting state in control group, and became active in stress group, where plenty of intracellular canaliculi were observed under the TEM. In stress+OM group, the dilated intracellular canaliculi lined with rare microvilli were founded. Enzyme cytochemistry staining showed that there was little black punctate enzyme reactive product scatted in intracellular canaliculi and the apical plasma membrane of parietal cells in control group, and there were large amounts of black enzyme reactive product accumulated at the intracellular canaliculi in stress group. Scarcely deposition of enzyme reactive product in intracellular canaliculi was observed in stress+OM group. CONCLUSION: The results indicate that the H⁺-K⁺-ATPase activity of gastric parietal cells increases under WRS, and is in accordance with ultrastructure changes. These findings suggeste that gastric acid might be one of the most important factors that result in stress ulcer.     

Effect of siRNA on myocarditis induced by MCMV in mice

AIM: To investigate the effect of siRNA on myocarditis induced by MCMV in BALB/c mice. METHODS: One handred and twenty male BALB/c mice (4 weeks old) were divided randomly into 6 groups with 20 mice each. Among these groups, one normal control group, one viral control group and 4 experimental groups were assigned. Mice in viral control and 4 experimental groups were inoculated intraperitoneally injection (ip) with 100 μL of DMEM medium containing TCID5010-4 MCMV, and followed by 200 μL of different doses of liposomally endocapsulated siRNA in 4 experimental groups and by 200 μL of vehicle solution of siRNA in viral control group 30 min later. Mice in normal control group were first inoculated ip 100 μL of DMEM medium and followed by 200 μL of vehicle solution of siRNA 30 min later. At day 7, 14, 21, 28, 35, 42, 49, 56, 63 and 70 of postinfection, all mice were killed and blood samples were collected for detecting serum zymogram (CK, CK-MB, GOT, LDH and LDH₁/LDH₂) and the anti-cardiac β₁ receptor autoantibody titer level. Hearts were removed aseptically for detecting cardiac histological lesions and ultrastructure changes. RESULTS: Decreased morbidity of myocarditis, lightened cardiac pathologic lesions and ultrastructural changes in 4 experimental groups were observed. Serum zymogram (CK, CK-MB, GOT, LDH and LDH₁/LDH₂) and β₁ autoantibody titer level in viral control group were significantly higher than those in normal control group, but zymogram and β₁ autoantibody titer levels in 4 experimental groups were between those in viral control group and normal control group. The activities of CK, CK-MB, GOT, LDH and LDH₁/LDH₂ and β₁ autoantibody titer level decreased accompanied with siRNA dose increasing. These effects were in a dose dependent manner. CONCLUSION: siRNA protects myocardial tissue against MCMV infection.