| Objective: In this study, Banxia Baizhu Tianma Modified Decoction(BBTMD) is administrated to obesity-related hypertensive rats induced by high-fat-diet. The objective of this study takes the hypothalamus and aorta as target organ and the leptin/leptin receptor mediated JAK2/STAT3 pathway of hypothalamus as observation point, to observe the pharmacodynamy and pharmacologic mechanism of anti-hypertensive and weight loss effect of BBTMD. Thus, we hope to provide new insight and new therapeutic targets for obesity-related hypertension essentially and prevent the cardiovascular events effectively.Methods:1. The establishment of obesity-related hypertension rats: 143 wistar rats were fed with high-fat diet while 16 wistar rats were fed with normal diet for 25 weeks. 63 from 143 rats were selected into model group with the standard that both body weights and blood pressure were 25% more than those of control group after 25 weeks. Body weights, body lengths and blood pressure were measured regularly. The concentration of serum triglyceride(TG), total cholesterol(TC), high density lipoprotein cholesterol(HDL-C) and low density lipoprotein cholesterol(LDL-C) in serum was measured by biochemical methods, and the level of serum leptin(Lep), angiotensin?(Ang?), endothelin-1(ET-1) and nitric oxide(NO) in serum were determined by ELISA. Morphological changes of aorta, left ventricular, kidney and liver were observed by HE staining.2. The pharmacological study of BBTMD in the treatment of obesity-related hypertension by regulating hypothalamic function: 33 model rats were randomly divided into HBBTMD group(8, 9.2 g?kg-1?d-1), LBBTMD group(8, 4.6 g?kg-1?d-1), TEL group(8, 3.4 mg?kg-1?d-1) and model group(9, normal saline 2ml?d-1). Intervention groups and control group(10, normal saline 2ml?d-1) rats were given drugs or saline by intragastrically for 12 weeks. Body weight and blood pressure were measured regularly. The concentration of serum TG, TC, HDL-C and LDL-C were measured by biochemical methods, and serum Ang?, Lep, NPY and NO were assayed using ELISA kits. Morphological changes of aorta and adipose tissue by HE staining. The distribution of AT1 R and LepR on aorta and hypothalamus were observed by immunohistochemical staining. Levels of mRNA expression of LepR, AT1 R, JAK2, STAT3 and SOCS3 in aorta and hypothalamus were determined by quantitive real-time PCR(qRT-PCR). Levels of protein expression of LepR, AT1 R, JAK2, STAT3 and SOCS3 in hypothalamus were determined by western blotting.3. Pharmacological study of the regulation of BBTMD on JAK2/STAT3 signaling pathway of hypothalamus: to verify that BBTMD activate its efficacy through activating JAK2/STAT3 signaling pathway, AG490 was injected into the third ventricle of obesity-related hypertension rats. 12 rats of HBBTMD group were divided into AG490+HBBTMD group(6 rats) and HBBTMD group(6 rats). 12 rats of model group were divided into AG490+model group(6 rats) and model group(6 rats). The AG490+HBBTMD group and AG490+model group were given 5?l AG490(2?mol/ml) while HBBTMD group and model group were given equivalent volume of saline by intrathirdventrical injection. The protein expression of JAK2, STAT3 and SOCS3 of hypothalamus were determined by Western Blot.Results:1. Body weights and blood pressure of model group rats were increased significantly(P<0.05). The level of TC, LDL-C, Lep, ET-1, Ang? in serum of model group rats increased significantly(P<0.05), while NO was decreased(P<0.05). Endothelia injury, cardiac muscle cell hypertrophy, hepatic fat degeneration and glomerular necrosis were oberserved in model group by HE staining.2. Body weights and blood pressure of all medication groups decreased in different degree after drug intervenation for 12 weeks and among those HBBTMD group demonstrated the best efficay(P<0.05). The level of serum TC, LDL-C, Ang?, Lep, and NPY in serum of HBBTMD group decreased significantly(P<0.05) while NO increased significantly(P < 0.05). The level of TC, LDL-C of LBBTMD group decreased significantly(P<0.05). Aortic morphology of HBBTMD group was improved obviously and the size of lipocyte decreased. The density of AT1 R in aorta and hypothalamus of HBBTMD group decreased significantly(P<0.05). The density of LepR in hypothalamus of HBBTMD group increased(P<0.05) and in aorta decreased(P<0.05). The mRNA expression of JAK2, STAT3, SOCS3, LepR and AT1 R in aorta of HBBTMD group decreased significantly(P<0.05). The mRNA expression and protein expression of LepR, JAK2 and STAT3 in hypothalamus of HBBTMD group increased significantly(P<0.05) while AT1 R and SOCS3 decreased significantly(P<0.05). These results indicated that BBTMD may play a role in weight loss and anti-hypertension through regulating hypothalamic function and improving leptin resistance. The mechanism may be related to the fuction of JAK2/STAT3 signaling pathway.2. After injection of AG490 in the model group, the expression of protein of JAK2 and STAT3 decreased significantly(P<0.05) while the protein of SOCS3 increased significantly(P<0.05). After injection of AG490 in HBBTMD group, the expression of protein of JAK2 and STAT3 decreased significantly(P<0.05) while the protein of SOCS3 increased significantly(P<0.05), but JAK2 and STAT3 protein expression was slighter higher than the model group and AG490 + model group(P<0.05) while SOCS3 protenion expression in slighter lower(P<0.05). These results indicated that JAK2/STAT3 signaling pathway is indeed one of but not the only pathways mediated BBTMD's effects.Conclusion: Body weights, blood pressure, blood lipid and the level of Ang?, Lep and NPY in serum of obesity-related hypertension rats decreased significantly and NO increased significantly by BBTMD. The possible mechanism is that BBTMD can ameliorate leptin resistance by activating the JAK2/STAT3 signaling pathway in hypothalamus. |
PDF Full Text Request