The Regulatory Effect Of Exercise On KCNQ Channel In Smooth Muscle Cells Of Obese Hypertensive Rats Via PVAT Paracrine H₂S

Objective:This study aimed to explore the possible mechanism of the effect of exercise on PVAT paracrine hydrogen sulfide on vascular function in obese rats,By elucidating the effect of CSE synthesis of endogenous H₂S in mesenteric artery PVAT on the KCNQ channel,it provides new ideas for the possible mechanism of exercise regulating obesity and hypertension.Methods:5-week-old male SD rats were randomly divided into a low-fat diet group（N group）and a high-fat diet group（H group）.Exercise saline group（HE）,quiet block group（HCB）,and quiet saline group（HC）.The exercise group underwent 13-week（60 min,5 days a week）moderate-intensity(55-60%VO_2max)aerobic treadmill exercise;the rats in the blocking agent group were aseptically injected with the CSE blocking agent PAG at 50 mg/kg via intraperitoneal injection.The rats in the saline group were injected with the same amount of normal saline.3injections per week for 13 consecutive weeks.After the intervention,The biochemical method and enzyme-linked immunosorbent assay were used to detect the levels of blood glucose and lipid metabolism indexes and inflammatory factors in rats.Spectrophotometry was used to detect the content of H₂S in the serum and PVAT of the mesenteric artery of the rats.Tension and drug sensitivity,the protein expression level of the KCNQ channel in rat mesenteric artery,and the expression level of CSE protein in PVAT of the mesenteric artery were determined by western blot.One-way ANOVA was used for the results,LSD method（homogeneity of variance）or Games-Howell test（heterogeneity of variance）were used for comparison between groups,and the data before and after the experiment were tested for normal distribution.If it obeyed normal distribution,use a paired-sample T-test,otherwise,a nonparametric test was used,expressed as mean±standard error.Results:（1）Before exercise intervention,the body weight,Lee’s index,and systolic blood pressure of the rats in the H group were significantly higher than those in the N group（P<0.05）.After exercise intervention,compared with the HC group,the Lee’s index,systolic blood pressure and mean arterial pressure in the HE group were significantly decreased（P<0.05）;Compared with the HCB group,the Lee’s index was significantly lower in the HEB group（P<0.05）,and there was no significant difference in systolic and diastolic blood pressure.（2）Compared with the HC group,the HDL level in the HE group was significantly increased（P<0.01）,the LDL level was significantly decreased（P<0.01）,and the LDL and TC levels in the HEB group were lower than those in the HCB group;The level of Insulin in the HE group was significantly lower than that in HC group（P<0.05）,and there was no significant difference among the other groups;The levels of IL-6,hs-CRP,and TNF-αin the HE group were significantly lower than those in the HC group（P<0.05）,and IL-6 and hs-CRP in the HEB group were significantly lower than those in the HCB group（P<0.05）.（3）The content of H₂S in the blood of rats in the HE group was significantly higher than that in the HC group（19.50±1.86,P<0.05）;Compared with the HC group,the content of H₂S in the PVAT of the mesenteric artery in the HE group was significantly increased（1141.66±68.64,P<0.05）,and the HEB group was significantly lower than the HE group（1047.45±13.05,P<0.05）,and there was no significant difference between the HCB group and the HEB group.（4）After pre-incubation with Retigabine,XE-991,and 4-AP,the maximum tension in the HE group was significantly lower than that in the HC group（P<0.05）,and there was no significant difference between the HEB group and HCB group;The results of the p EC₅₀ value showed that there was no significant difference among the groups.The results of the concentration gradient tension showed that the tension after transfer of the bath solution in each group was lower than the tension level without the transfer of the bath solution,but there was no significant difference.（5）Compared with the HC group,the protein expressions of KCNQ1 and KCNQ5 in the HE group were significantly increased（P<0.05）,and the protein expression of KCNQ4 in the HCB group was significantly decreased（P<0.05）;Compared with the HE group,the expressions of KCNQ1 and KCNQ4 in the HEB group were significantly decreased（P<0.05）;the protein expression of CSE in the HE group was significantly higher than that in the HC group（P<0.05）;Compared with the HE group,the HEB group of CSE was significantly lower（P<0.01）.Conclusions:（1）Long-term intraperitoneal injection of CSE blockers inhibited the synthesis of endogenous H₂S and weakened the regulation effect of exercise on blood pressure,indicating that PVAT paracrine H₂S plays an important role in the intervention of exercise in obesity and hypertension.（2）The regulation of obese hypertension by PVAT paracrine H₂S may depend on the expression of the KCNQ channel,and its subunit KCNQ4 may play a key role.