ABSTRACT
Objective To study the long-term effect of administration(6 months) with transient receptor potential vanilloid 1(TRPV1) agonist capsaicin on contractile reactivity of thoracic aorta in C57BL/6J mice.Methods Tow-month-old male C57BL/6J mice were received normal diet group(n=12) or capsaicin group(normal diet plus capsaicin,n=12).Tail-cuff systolic blood pressure(SBP) was examined at the baseline and at the end of the intervention.After 6-month treatment period,carotid artery blood pressure and heart rate were determined by catheterization,and the aortic contractile response was examined using isometric myograph(Danish Myotech Technology,Denmark).Plasma levels of renin,angiotensin Ⅱ(Ang Ⅱ) and aldosterone were determined.Vascular smooth muscle cells(VSMC) were obtained from thoracic aorta of mice and cultured.Angiotensin Ⅱ type 1 receptor(AT1R) protein expression was detected by western blot.Calcium imaging was detected in cultured VSMC using the fluorescent dye technique.Results Systolic blood pressure,invasive carotid artery blood pressure and heart rate have no difference between two groups.No differences was found in PE-induced contraction response in thoracic aorta;while Ang Ⅱ induced contractility of aortic ring was lower in mice with capsaicin than control group [capsaicin:(37.5?1.6)% vs(59.8?1.4)%,P
ABSTRACT
Objective To reproduce a rat model of metabolic syndrome (MS) to analyze the variations of related gene expression. Methods 30 male rats aged 8w were randomly divided into two groups, the rats in NC group (control) were fed with normal diet (10% fat and 0.5% salt ), and those in metabolic syndrome (MS) group with high fat diet (49% fat and 2% salt). The body weight, blood pressure, fasting blood glucose (FBG), blood lipid and fasting insulin level were serially measured. Such feedings were continued for 24 weeks, and then the intraperitoneal glucose tolerance test and hyperinsuline-euglycemic gomphosis test were performed, and carotid arterial pressure and visceral fat were measured. RT-PCR was used to detect the genes related to energy consumption, glucose-lipid metabolism in white adipose, brown adipose and muscle tissue. Results Compared with NC group, all the variables were increased significantly, such as body weight, visceral fat weight, blood pressure, serum levels of TG and FFA. A marked insulin-resistance and decreased glucose tolerance were found in MS group. Hyperinsuline-euglycemic gomphosis test revealed that the mRNA expression of 23 genes related to glucose-lipid and energy metabolism changed significantly in white adipose, brown adipose and muscle tissue in MS group as compared with NC group. Conclusion Prolonged high fat plus high salt diet may cause the clinical features of MS in rats. The changes in various genes may be involved in the mechanisms involved in the pathogenesis.
ABSTRACT
Objective To investigate the features of vascular damage in metabolic syndrome (MS) by a comparison of changes in vascular structure and function between spontaneous hypertension (SH) and MS in rats. Methods Pathological study of changes in arteries was carried out. The contractile response of aorta ring and the expression of RhoA, ROCK, eNOS and iNOS were also determined. Results Besides the thickening of arterial wall and proliferation of both intima and smooth muscle layer, marked infiltration of inflammatory cell appeared in large and medium arteries of MS rats, and obvious hyaline degeneration was found in mesenteric arterioles. Moreover, the relaxant response of aorta ring was weakened markedly in MS rats, while the contractile response increased in SH rats dramatically. The expression of RhoA, ROCK increased and that of NOS decreased in MS rats, but the up-regulation of the RhoA, ROCK expression was not as much as in SH rats. Conclusion The damage to both arterial structure and function was much more serious in MS rats than that in SH rats. Activation of RhoA/ROCK system and reduction of NOS expression might be involved in the mechanism.