Effect of GYY4137 on cytosolic lipid decomposition in mouse primary hepatocytes

AIM: To evaluate the effect of GYY4137, a novel hydrogen sulfide (H₂S) donor, on cytosolic lipid decomposition in mouse primary steatosis hepatocytes. METHODS: Oleic acid (OA) was used to induce hepatic steatosis model in vitro. The C57BL/6 mouse primary hepatocytes isolated and cultured by 2-step in situ perfusion were divided into 4 groups:the cells in control group were incubated with normal medium for 54 h; the cells in model group were incubated with OA at 1.2 mmol/L for 48 h followed by serum-free phenol red-free RPMI-1640 for 6 h; the cells in H₂S group or DL-propar-gylglycine (PAG; an inhibitor of cystathione γ-lysase, inhibiting H₂S synthesis) group were incubated with OA at 1.2 mmol/L for 48 h followed by serum-free phenol red-free RPMI-1640 which contained 1 mmol/L GYY4137 or 200 μmol/L PAG for 6 h. The glycerin release and the protein expression of hormone-sensitive lipase (HSL) in the cells were mea-sured. RESULTS: Compared with model group, the glycerin release and the protein expression of phosphorylated HSL (p-HSL) in H₂S group decreased significantly, while those increased significantly in PAG group. CONCLUSION: In steatosis hepatocytes, exogenous H₂S possibly decreases cytosolic lipid decomposition by decreasing the protein level of p-HSL.     

Preventive effect of Guizhi decoction on myocardial injury after chemical sympathectomy

AIM: To investigate the preventive effect of Guizhi decoction on myocardial injury after chemical sympathectomy induced by 6-hydroxydopamine (6-OHDA).METHODS: Wistar rats (n=54) were randomly divided into 6 groups. Methycobal and Guizhi decoction (with different proportions between Ramulus Cinnamomi and Radix paeoniae Alba at 2:1, 1:2 or 1:1) were pre-administered to the rats. Immunohistochemical method was used to observe the cardiac sympathetic nerve distribution. The contents of tyrosine hydroxylase (TH), choline acetylaminotransferase (ChAT) and growth-associated protein 43 (GAP-43) in the left ventricle were measured by ELISA. The serum levels of myocardial enzymes and morphology of myocardial tissues were also observed.RESULTS: 6-OHDA successfully induced cardiac sympathetic denervation as the contents of TH and GAP-43 in the left ventricle declined significantly. Compared with model group, the content of TH was elevated in both methycobal group and Guizhi decoction groups, while the content of GAP-43 was elevated only in Guizhi decoction groups. The serum levels of myocardial enzymes and the histopathological changes of the cardiac tissues were deteriorated after injection of 6-OHDA, indicating that the myocardial injury was established. Methycobal and Guizhi decoction normalized the abnormal change. Guizhi decoctions at 2:1 and 1:1 showed the best efficacy.CONCLUSION: 6-OHDA-induced sympathetic denervation causes myocardial injury. Guizhi decoction with the proportions between Ranulus Cinnamomi and Radix paeoniae Alba at 2:1 and 1:1 effectively alleviate the myocardial injury after cardiac sympathetic denervation induced by 6-OHDA.     

Effect of GLP-1 receptor agonist on lipolysis in adipose tissue of obese mice and its underlying mechanism

AIM: To investigate the effects of glucagon-like peptide-1(GLP-1) receptor agonist exendin-4 on white adipose tissue (WAT) and the underlying mechanisms. METHODS: Male C57BL/6J mice (8 weeks) were challenged by high-fat diet for 12 weeks, and were randomly divided into saline group and exendin-4 group. The mRNA expression of sirtuin 1(SIRT1), adipose triglyceride lipase (ATGL), TNF-α and adiponectin of WAT was detected by real-time PCR. 3T3-L1 adipocytes or mouse embryonic fibroblasts cells were treated with exendin-4 for 24 h. The protein levels of SIRT1, ATGL and hormone-sensitive lipase (HSL) were determined by Western blot.RESULTS: Exendin-4 significantly decreased epididymal fat weight, fasting blood glucose and serum triglyceride levels (P<0.05), and reduced body weight and serum TNF-α level. The mRNA expression of SIRT1, ATGL and adiponectin in WAT was all significantly up-regulated by exendin-4, which were contrary to the down-regulation of TNF-α mRNA expression (P<0.05). Exendin-4 promoted the protein expression of SIRT1, ATGL, and HSL in 3T3-L1 adipocytes in a dose-dependent manner. Less lipid droplets with up-regulation of lipolytic protein expression were observed when combined with SIRT1 agonist treatment, which were suppressed by SIRT1 inhibitor. Deletion of SIRT1 led to larger adipocytes with more lipid droplets, and the effect of exendin-4 on the lipolysis disappeared when SIRT1 was deficient.CONCLUSION: Exendin-4 promotes lipolysis in WAT of obese mice via activation of SIRT1.     

Integrative therapy using coenzyme Q10 and minocycline in 1-methyl-4-phenylpyridinium-induced hemiparkinson rats

AIM：To investigate the integrative treatment of both coenzyme Q10 (CoQ10) and minocycline in the rats intranigrally intoxicated with 1-methyl-4-phenylpyridinium (MPP+). METHODS：The rat model of Parkinson disease (PD) was established by intranigral microinjection of MPP+. The degree of microglial activation was measured by immunofluorescent density of OX-42 (a microglia marker) in the substantia nigra (SN). The number of viable dopaminergic neurons was determined by counting the tyrosine hydroxylase (TH) positive neurons in the SN. The behavioral performances were revealed with the number of apomorphine-induced rotations, score of forelimb akinesia and vibrissae-elicited forelimb placing asymmetry. RESULTS：Pretreatment with CoQ10 or intracerebroventricular (icv) posttreatment with minocycline alone provided partial attenuation against MPP+-induced locomotor defects. Integrative therapy provided enhanced beneficial effects, and resulted in a significant attenuation of locomotor disability than any single therapy (all P<0.01). The results of immunohistological analysis showed that the TH positive neurons were maximally protected by integrative therapy compared with minocycline group and CoQ10 group (P<0.01) . CONCLUSION：The integrative therapy of CoQ10 combined with minocycline may offer additional therapeutic benefit to MPP+ -induced hemiparkinson rat model. Such neuroprotective strategy of targeting different aspect of the neurodegenerative phenotypes may highlight a new therapeutic strategy for future management of PD.     

CX3CR1 mediates the neuroprotective effect of triptolide on 1-methyl-4-phenylpyridinium-induced hemiparkinson rats

AIM: To investigate the effect of triptolide on the inhibition of microglial activation in 1-methyl-4-phenyl pyridinium (MPP⁺)-induced hemiparkinson disease rats.METHODS: The rat model of Parkinson disease was established by intranigral injection of MPP⁺. The rats were randomly divided into sham group, MPP⁺ group, triptolide group and vehicle group. The survival of dopaminergic neurons was detected by the immunofluorescence of tyrosine hydroxylase (TH) in the substantia nigra (SN). The activation of microglia was determined by immunofluorescence of OX-42 (microglia marker) in the SN. The expression of chemokine receptor CX3CR1 in SN was measured by Western blotting.RESULTS: Intranigral injection of MPP⁺ increased the fluorescence intensity of the microglial marker, and promoted DA neuron degenerative death. Immunohistological analysis showed that the OX-42 density was decreased (P<0.01) and tyrosine hydroxylase (TH) positive neurons were increased in the triptolide group (P<0.01). The expression of CX3CR1 was lower in triptolide group than that in model group (P<0.05).CONCLUSION: Triptolide may improve PA neurons function in MPP⁺-induced rats through inhibiting CX3CR1 expression and microglial activation.     

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.     

Comparison of central noradrenaline levels and its TH,MAOA between chronic psycological stress and physical exercise in rats

AIM: To investigated the changes of hippocampus noradrenaline levels and its tyrosine hydroxyase (TH), monoamine oxidase A (MAOA) expressions during chronic psycological stress procedure and physical exercise in rats. METHODS: Male Wistar rats (n=24) were randomly assigned to three conditions: (1) restraint stress (S) at 6 h/d for 3 weeks; (2) 24 h access to activity wheel running (E) for 4 weeks; (3) a sedentary control group (C). Levels of NE were assayed by high performance liquid chromatography with electrochemical detection. Protein expression of TH and MAOA were detected by Western blotting. RESULTS: Compared to C, weight loss and sucrose consumption rate decrease were induced in S, and NE was lower while TH and MAOA expressions increased significantly. In E group, NE was higher and TH, MAOA increased distinctly. CONCLUSION: It is suggested that hippocampus NE level may play an important role in the mechanism on the protection of physical exercise to chronic psycological stress, there is no close connection between NE change and TH, MAOA. Other mechanisms may exist.     

Effects of cordycepin on motor and cognition in Parkinson disease mice induced by MPTP

AIM:To investigate the effects of cordycepin on the motor and cognition in Parkinson disease mice induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). METHODS:C57BL/6 mice were intraperitoneally injected with MPTP at a dose of 30 mg/kg daily for consecutive 8 d to establish the model of Parkinson disease. HE staining was used to observe the cell number in the substantia nigra pars compacta (SNpc) from the mice. Western blot was used to detect the protein level of tyrosine hydroxylase (TH) in substantia nigra (SN). The effects of cordycepin on the motor, emotional change and cognitive behavior of the Parkinson disease mice were examined by open-field test (OFT), sponta-neous alternating behavior (SAB) and water maze test (WMT), respectively. RESULTS:Cordycepin significantly reduced the apoptosis of cells in SNpc and reversed the decrease in the expression of TH in SN induced by MPTP (P<0.05). Furthermore, cordycepin was able to improve the average speed in OFT (P<0.05), and increased the total number of arm entry and the accuracy in SAB (P<0.05), but had no obvious effect on the latency in WMT. CONCLUSION:Cordycepin is capable of attenuating the impairments of motor and explorative ability in the early stage of Parkinson disease mice, but does not alter the cognitive dysfunction.     

Effects of ketamine on expression of α-synuclein in Parkinson's disease mice

AIM:To observe the effect of treatment with ketamine (Ket) on the expression of α-synuclein (α-Syn) in a mouse model of Parkinson's disease (PD) induced by neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). METHODS:Healthy male mice (n=48) were randomly divided into 3 groups:NaCl group (control group), MPTP group (model group) and MPTP+Ket group (treatment group). Rotarod experiment and gait analysis system were used to evaluate the behavioral differences among the animals in 3 groups. Immunohistochemical staining was used to observe the change of tyrosine hydroxylase (TH) expression in neurons of substantia nigra. Immunofluorescence staining and Western blot were used to detect the protein expression of α-Syn in substantia nigra and striatum region. RESULTS:According to the results of rotarod experiment and gait analysis system, the number of laps and the step length in MPTP group were reduced significantly as compared with NaCl group (P<0.05), while those in MPTP+Ket group showed significant increases as compared with MPTP group (P<0.05). The results of immunohistochemical staining and immunofluorescence staining indicated that the number of dopaminergic neurons in substantia nigra was decreased, and the fluorescence intensity for α-Syn in substantia nigra and striatum was increased in MPTP group as compared with NaCl group (P<0.05). The number of dopaminergic neurons in substantia nigra was increased, and the fluorescence intensity in substantia nigra and striatum was decreased in MPTP+Ket group as compared with MPTP group (P<0.05). The results of Western blot also indicated that the protein expression of α-Syn in substantia nigra and striatum region augmented significantly in MPTP group as compared with NaCl group (P<0.05). Compared with MPTP group, the protein expression of α-Syn in MPTP+Ket group was significantly decreased (P<0.05). CONCLUSION:Ketamine has a convinced inhibitory effect on the abnormal expression of α-Syn in the substantia nigra and striatum region of the PD mice.     

Effect of myocardial ischemia on expression of natriuretic peptide receptors in rat medulla oblongata

AIM:To evaluate the expression of natriuretic peptide receptor A (NPR-A) and C (NPR-C), choline acetyltransferase (ChAT) and tyrosine hydroxylase (TH) in the ventral medulla oblongata after myocardial ischemia in the rats. METHODS:All rats were randomly divided into blank control group, sham group and myocardial ischemia group. After the myocardial ischemia model was established, the rats were sacrificed, and the expression of NPR-A, NPR-C, ChAT and TH in the rostral ventral medulla oblongata and caudal ventral medulla oblongata was detected by Western blotting on day 3, day 7, day 14, day 18 and on day 28. RESULTS:On the above days after modeling, the expression of NPR-A in ventral medulla oblongata of the rats was significantly increased (P<0.05). The expression of NPR-C was also increased, but later than NPR-A. The expression of TH was significantly decreased (P<0.05). The expression of ChAT in the rostral ventral medulla oblongata was lower than that in blank control group (P<0.05), and had no significant difference as compared with blank control group in the caudal ventral medulla oblongata. CONCLUSION:In medulla oblongata, the expression of NPR-A and NPR-C in the central cardiovascular region significantly increases after myocardial ischemia, while the expression of ChAT and TH decreases markedly. The natriuretic peptide, ChAT and TH may participate in the autonomic nervous control of cardiovascular system after myocardial ischemia.     

Pituitary tumor model induced by diethylstilbestrol in rats

AIM:To establish a stable pituitary tumor model by diethylstilbestrol(DES) induction in Wistar rats. METHODS:Wistar-Furth rats were randomly divided into DES treatment group, arachis oil treatment group and control group. The behavior changes and body weight of the rats were recorded. Ten rats in DES group and 5 in each of the other 2 groups were sacrificed after 4, 8 and 12 weeks, respectively. The weight and the histological and morphological changes of the pituitary gland, serum prolactin(PRL) level, and expression of CD31 were detected. RESULTS:Trichomadesis and behavior changes such as slowdown and anorexia were observed in a majority of rats in DES group 2 weeks after treatment. The increase in body weight of the rats in DES group was significantly slower than that in the other 2 groups. Tumor formation was detected in DES group, and abnormal cells were found after HE staining in despite of the sexes. CD31 expression in DES group was significantly higher than that in the other 2 groups. Serum PRL and the weight of pituitary gland were higher in DES group. CONCLUSION:Pituitary tumor model induced by DES in Wistar-Furth rats is a stable and convenient pituitary tumor model.     

Effect of insulin resistance on fatty liver in high-fat diet-fed mice

AIM: To study the influence of insulin resistance on fatty liver in the mice fed with high-fat diet (HFD).METHODS: Male 8-week-old C57BL/6J mice were randomly divided into HFD group (with 60% calories by high saturated fatty acid) and control group (with chow diet).The mice in both groups were fed for 12 weeks. The body weight, liver weight, serum triglyceride (TG) and total cholesterol (TC), and blood glucose and insulin levels were measured. Hyperinsulinemic euglycemic clamp experiment was applied to reflect insulin sensitivity. The lipid deposition in the liver was analyzed by HE staining, Sudan IV staining and measurement of liver fat content. The phosphorylation levels of IRS1 and Akt, and the protein levels of SREBP-1 and FAS were determined by Western blot to reflect the activities of insulin signaling and lipid synthesis.RESULTS: Compared with control group, the body weight and liver weight were significantly increased in HFD group. TG and TC contents in serum and liver tissues were remarkably increased in HFD group. High-fat diet induced insulin resistance, as evidenced by increased serum insulin levels, reduced glucose infusion rate and decreases in IRS1 and Akt phosphorylation levels. In livers of HFD group, HE staining showed that the cytoplasm of hepatocytes was filled with vacuoles. Sudan IV staining also displayed that many different sizes of red lipid drops existed in the hepatocytes, and the protein levels of SREBP-1 and FAS were significantly increased. In primary normal hepatocytes with exogenous oleic acid intervention for 48 h, the phosphorylation levels of IRS1 and Akt were reduced, and the protein expression of SREBP-1 and FAS was significantly increased in a dose-dependent manner.CONCLUSION: Feeding with HFD leads to insulin resistance, resulting in activation of lipid synthesis and accumulation of lipid deposition in the liver, thus inducing fatty liver.     

Role of SIRT1/AMPK pathway in early intervention of Lira alleviating non-alcoholic fatty liver disease caused by high-fat diet in rats

AIM To investigate the effect of early intervention of glucagon-like peptide-1 (GLP-1) receptor agonist liraglutide (Lira) on oxidative stress, glucose tolerance, hepatic steatosis and insulin resistance of the rats with high-fat diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD), and to explore the role of silent information regulator 1 (SIRT1)/AMP-activated protein kinase (AMPK) signaling pathway in this process. METHODS Twenty-four male SD rats were randomly divided into normal diet (ND) group, HFD group and HFD+Lira group, with 8 rats in each group. After 1 week of adaptive feeding, the rats in HFD+Lira group were subcutaneously injected with Lira (200 μg/kg) per day at a fixed time point, while the rats in the remaining 2 groups were injected with normal saline at the same volume. During the intervention, the body weight, hair, appetite, defecation and activity of the rats were observed to adjust the dosage timely. The body weight, food intake and blood glucose were recorded weekly. Glucose tolerance test was performed at the end of the 16th week. At the end of the 18th week, hyperinsulinemic euglycemic clamp test was conducted after anesthesia. Blood was taken from the carotid artery. The liver and adipose tissues from different parts were taken after death. The serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and other indicators were detected. HE staining was used to observe the pathological changes of the liver tissue. Lipid accumulation in the liver tissues was observed by oil red O staining. Liver fibrosis was observed by Masson staining and Sirius red staining. Fluorescence staining for reactive oxygen species (ROS) was used to observe the oxidative stress in the liver. The expression of GLP-1 receptor in the liver was observed by immunofluorescence staining. The expression and localization of SIRT1 and phosphorylated AMPK at Thr172 [p-AMPK (Thr172)] were observed by immunohistochemical staining. The protein levels of AMPK, p-AMPK (Thr172), SIRT1, phosphorylated sterol regulatory element binding protein-1c at Ser372 [p-SREBP-1c (Ser372)], phosphorylated acetyl coenzyme A carboxylase at Ser79 [p-ACC (Ser79)], carnitine palmitoyltransferase 1A (CPT1A) and fatty acid synthase (FAS) in liver tissues were determined by Western blot. RESULTS The results of HE and oil red O staining of rat liver tissues in HFD group confirmed the structural disorder and serious lipid accumulation, while Masson and Sirius red staining showed severe fibrosis, suggesting the successful establishment of NAFLD rat model. Compared with ND group, the levels of total cholesterol (TC), triglyceride (TG), AST and ALT in serum, and the levels of malondialdehyde (MDA), TC, TG and ROS in liver tissues in HFD group were significantly increased (P<0.01), while the activity of superoxide dismutase (SOD) was decreased (P<0.01). The protein levels of p-AMPK (Thr172), SIRT1, p-SREBP-1c (Ser372), p-ACC (Ser79) and CPT1A in the liver tissues were significantly reduced (P<0.05 or P<0.01), while the expression of FAS was increased （P<0.01）. Compared with HFD group, lipid accumulation and fibrosis in the liver tissues of the rats in HFD+Lira group were significantly attenuated, the serum levels of TC, TG, AST and ALT, and MDA, TC, TG and ROS in liver tissues were markedly reduced (P<0.05 or P<0.01), while SOD activity was increased (P<0.05). The protein levels of p-AMPK (Thr172), SIRT1, p-SREBP-1c (Ser372), p-ACC (Ser79) and CPT1A in the liver tissues were significantly increased (P<0.05 or P<0.01), while the expression of FAS was decreased （P<0.01）. CONCLUSION Lira attenuates insulin resistance, oxidative stress and fibrosis, and improves liver lipid metabolism in the rats with NAFLD induced by HFD, which may be mediated by SIRT1/AMPK signaling pathway.     

Effect of human β-NGF gene-modified bone marrow-derived mesenchymal stem cells on rotational behavior of rats with Parkinson disease

AIM：To investigate the effect of human β-nerve growth factor (β-NGF) gene-modified bone marrow-derived mesenchymal stem cells (MSCs) transplantation on the rotational behavior improvement in a rat model of Parkinson disease (PD). METHODS：The rat model of PD was established successfully and the animals were divided into 4 groups:β-NGF-MSCs group (transplanted with 5×105 β-NGF-engineered MSCs), MSCs group (transplanted with 5×105 MSCs), DMEM/F12 group (5 μL transplantation medium was injected in the right striatum of the rats) and PD model group (without transplantation). The rotational scores were assessed 2 weeks, 4 weeks and 6 weeks after transplantation. At different time points after transplantation, the rats were tested for apomorphine (APO)-induced rotational behavior and the brains of the PD model rats were examined by fluorescence microscopy and immunohistochemical staining. RESULTS：Transplantation of human β-NGF gene-modified MSCs effectively improved the behavioral performance in the rats. At the 2nd, 4th and 6th weeks after cell transplantation, the rotational frequencies after injection of APO decreased significantly in β-NGF-MSCs group compared with MSCs group and PD group (P<0.05). Both β-NGF gene-modified MSCs and MSCs survived in the brains of PD model rats, had good compatibility with the host cells, and showed no signs of destroying the host and the glial cicatrisation. The β-NGF gene-modified MSCs expressed β-NGF stablely in the brains of PD model rats, and showed obvious improvement of the rotational behavior in the PD model rats induced by APO compared with MSCs group. CONCLUSION:The behavior of the rats with PD is significantly improved by transplanting β-NGF-modified MSCs in right striatum, and β-NGF gene therapy has potential clinical value．     

Effects of pioglitazone on myocardial energy metabolism and hemodynamics in rats with myocardial infarction

AIM: To observe the effects of pioglitazone on myocardial energy metabolism and hemodynamics in rats with heart failure after myocardial infarction (MI). METHODS: The model of MI was established by ligation of left anterior descending artery. The 20 surviving rats were randomly divided into MI group (n=10) and pioglitazone intervention group (P group,n=10, pioglitazone 3 mg·kg^-1·d^-1 orally). The sham-operated rats (SH, n=10) served as controls. Hemodynamic parameters were measured. The ratio of left ventricular weight to body weight (LVW/BW) and the ratio of right ventricular weight to body weight (RVW/BW) were calculated after 8-week treatment. The expression of PPARγ was examined by Western blotting. Mitochondrial respiratory function was determined by Clark oxygen electrodes. The size of adenine acid pool (ATP, ADP and AMP) in mitochondria was measured by HPLC. The adenine nucleotide translocator(ANT) activity was detected by the atractyloside-inhibitor stop technique. RESULTS: Compared with SH group, the protein expression of PPARγ was significantly decreased in MI group (P<0.01). The mitochondrial respiratory activity, the transport activity of ANT and the high-energy phosphate content were decreased in MI group (P<0.01), and the hemodynamic parameters were in disorder (P<0.01). Compared with MI group, the protein expression of PPARγ in P group was significantly increased. The mitochondrial respiratory activity, the high-energy phosphate content, the transport activity of ANT were improved (P<0.01). However, the hemodynamic parameters were not significantly changed.CONCLUSION: Pioglitazone increases the protein expression of PPARγ and improves myocardial energy metabolism in the development of heart failure in the rat model of myocardial infarction, but dose not change the hemodynamic parameters significantly.     

Effect of Kechuanning on airway remodeling and protein level of p-ERK1/2 in lung tissues of asthmatic rats induced by virus

AIM:To investigate the effect of Kechuanning on airway remodeling and the protein level of p-ERK1/2 in lung tissues of asthmatic rats induced by virus. METHODS:The asthmatic rat model induced by respiratory syncytial virus was established. The experimental rats were divided into normal group, asthma model group, low dose (0.33 mL/kg), middle dose (3.0 mL/kg) and high dose (10 mL/kg) of Kechuanning groups, and PD98059 (3 mg/kg) group. The airway responsiveness of the rats was measured by animal ventilator. The pathological changes of the lung tissues were observed by HE staining. PAS staining and Masson staining were used to observe goblet epithelial cells metaplasia and airway collagen deposition. The expression of matrix metalloproteinases-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in the lung tissues of the rats was detected by immunohistochemical staining. The protein levels of ERK1/2 and p-ERK1/2 were determined by Western blot. RESULTS:Compared with model group, the airway responsiveness of the rats in middle dose and high dose of Kechuanning groups was significantly decreased (P<0.01), the injury of lung tissues was significantly decreased, the goblet epithelial cells metaplasia and airway collagen deposition were significantly reduced (P<0.01), and the expression of MMP-9 and TIMP-1 in the lung tissues was also significantly decreased (P<0.01). In addition, the protein level of p-ERK1/2 in high dose of Kechuanning group was significantly decreased compared with model group (P<0.01). CONCLUSION:Kechuanning may treat asthma by regulating the expression of p-ERK1/2 in the lung tissues and improving the airway remodeling symptoms of asthmatic rats induced by virus.     

Effect of intravenous injecting plasmid encoding interleukin-19-IgG on experimental autoimmune myocarditis in rats

AIM: To evaluate the effect of intravenous injecting plasmid encoding interleukin-19-IgG on experimental autoimmune myocarditis (EAM) in rats.METHODS: Cardiac myosin was emulsified with equal volume of complete Freund's adjuvant. The animal model of EAM was established by injecting with the preparation in both footpads of the Lewis rats. The rats were intravenously injected with the plasmid encoding IL-19-IgG on day 6. Echocardiography was performed before the rats were sacrificed on day 17. The effect of IL-19-IgG plasmid injection was evaluated by measuring the heart weight/body weight, myocarditis area, relative expression levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in the hearts. The mRNA expression levels of related cytokines including IL-18, IL-1β, IL-12p35 and IFN-γ were detected.RESULTS: The rats in model group showed significant myocardial damage and a decrease in the left ventricular functions. The rats in the treatment group injected with IL-19-IgG plasmid showed an improvement of the cardiac functions. The ratio of heart weight/body weight, the area of myocarditis and the mRNA levels of ANP and BNP were significantly lower in IL-19-IgG treatment group than those in model group. The mRNA levels of IL-18, IL-1β, IL-12p35 and IFN-γ were also significantly decreased in IL-19-IgG treatment group.CONCLUSION: Intravenous injection of plasmid encoding IL-19-IgG effectively prevents the development of the left ventricular remodeling and myocardial damage in EAM rats.     

Inhibitory effect of aerobic exercise on left ventricular remodeling and sympathetic neural remodeling in rats with heart failure after myocardial infarction

AIM: To investigate the effects of long-term aerobic exercise on the heart and sympathetic neural remodeling (structure and function remodeling) in heart failure rats induced by myocardial infarction. METHODS: Heart failure model after myocardial infarction was performed by ligating anterior descending coronary artery in the Wistar rats. Four weeks after operation, the rats were randomly divided into sham operation sedentary (S) group, heart failure sedentary (H) group and heart failure exercise (HE) group. The animals in HE group underwent 10-week treadmill running, while those in S group and H group were sustained in a resting state. The cardiac structure and function including left ventricular internal diameter at diastole (LVIDd), left ventricular internal diameter at systole (LVIDs), left ventricular anterior wall diameter at diastole (LVAWDd), left ventricular anterior wall diameter at systole (LVAWDs), left ventricular posterior wall diameter at diastole (LVPWDd) and left ventricular posterior wall diameter at systole (LVPWDs), and cardiac function parameters including fractional shortening (FS) and left ventricular ejection fraction (LVEF) were measured by echocardiography. The myocardium was collected for histopathological observation with Masson staining, and the collagen volume fraction (CVF) was determined. The concentrations of norepinephrine (NE) in the myocardium and plasma were measured by high-pressure liquid chromatography. The frequency domain analysis was applied for determining the heart rate variability (HRV) via subcutaneous recording electrode involving total power (TP), normalized low power (LFn), normalized high power (HFn) and LF/HF ratio. The mRNA expression of collagen type I (Col-I), collagen type III (Col-III), atrial natriuretic factor (ANF), α-myosin heavy chain (α-MHC), β-myosin heavy chain (β-MHC), sarcoplasmic endoplasmic reticulum Ca²⁺-ATPase (SERCA2a) was detected by real-time PCR. The protein levels of nerve growth factor (NGF) and its receptor (TrkA), and tyrosine hydroxylase (TH) were measured by Western blotting. RESULTS: (1) Compared with S group, body weight (BW), LVIDd, FS, LVEF, TP, HFn, the mRNA expression of α-MHC and SERCA2a, and the protein levels of NGF, TrkA and TH decreased (P<0.05). Left ventricular weight (LVW), left ventricular mass index (LVMI), LVAWDd, LVAWDs, LVPWDd, LVPWDs, CVF, plasma and myocardial NE content, LFn, LF/HF, and the mRNA expression of ANF, β-MHC, Col-I and Col-III increased (P<0.05) in H group. (2) Compared with H group, LVW, LVMI, LVIDd, FS, LVEF, TP, HFn, the mRNA expression of α-MHC and SERCA2a, and the protein levels of NGF, TrkA and TH were raised (P<0.05), while CVF, plasma and myocardial NE content, LFn, LF/HF, and the mRNA expression of ANF, β-MHC, Col-I and Col-III decreased (P<0.05) in HE group. CONCLUSION: Long-term aerobic exercise training leads to inhibition of heart and sympathetic neural remodeling and improvement of cardiac function and autonomic modulation in the rats after myocardial infarction.     

Mechanisms of hyperglycemia induced by immunosuppressant FK506

AIM：To investigate the effect of immunosuppressant FK506 on serum glucose in rats and to explore its mechanism. METHODS：Sprague-Dawley rats (n=12) were randomly divided into drug group and normal group. The rats in drug group were intraperitoneally injected with FK506 at dose of 1 mg·kg-1·d-1 and the rats in normal group received saline (1 mL·kg-1·d-1, ip) for 14 d. The fasting weight and fasting glucose were regularly measured every 2 d. Visceral fat was isolated from the rats at the end of experiment. The mRNA expression of adiponectin, leptin, visfatin, resistin, retinol-binding protein 4 (RBP4) and peroxisome proliferator-activated receptors γ (PPAR-γ) was determined by real-time fluorescence quantitative PCR. The protein expression of PPAR-γ and adiponectin was measured by Western blotting. RESULTS：Compared with normal group, the concentration of fasting blood glucose in model group was significantly increased from the 10th day (P<0.05). At day 14, the fasting blood glucose of the model group increased from (5.10±062) mmol/L to (7.73 ± 0.73) mmol/L. No significant change of blood glucose in normal group between the 10th day and the 14th day ［from (4.66 ± 0.32) mmol/L to (5.80±0.10) mmol/L］ was observed. Compared with normal group, the mRNA expression of PPAR-γ, adiponectin and leptin in the adipose tissue of model group was significantly decreased (P<001), whereas the expression of visfatin, resistin and RBP4 was significantly increased (P<005). Compared with normal group, the expression of PPAR-γ and adiponectin in model group was decreased (P<001). CONCLUSION：FK506 may decrease the expression of PPAR-γ to change the expression of adipocytokines and induce hyperglycemia in rats.