Antioxidant Effect And Mechanism Of Sequoyitol On Vascular Injury In Type2Diabetic Rats

Objective: To observe the role of sequoyitol on antioxidant effect in the type2diabeticrats of vascular injury and explore its mechanisms.Methods:1. In vivo tests: The model of type2diabetic rats was induced by one-timeabdominal injection35mg/kg STZ solution and added with a high-fat, high-glucose dietfor4weeks. Successful modeling rats (blood glucose contant≥11.1mmol·L-1) wereused in this study. Type2diabetic rats were randomly divided into five groups,modelgroup (5.0ml/kg), sequoyitol of high,medium and low dosages groups(50,25,12.5mg/kg),acarbose(20mg/kg)positive control group.In addition, the control (5.0ml/kg)negative control group was added. All groups were fed with these dosages dailyfor6weeks. Fasting glucose was measured every2weeks before and duringadministration.After6weeks, collected blood from abdominal aortas.The thoracic aorticring of rats was mounted on a bath system.The relaxation responses induced byacetylcholineor and sodium nitroprusside were measured.Basic pathologic changes wereobserved by HE stain.Collagen fibres changes were observed by MASSON stain.Thelevel of NO in serum was detected by nitrate reduction.The levels of T-AOC, H2O2in serum were detected by colorimetry.The expression of eNOS mRNA, NOX4mRNAin aortas were observed by real time PCR.The expression of eNOS and NOX4protein in aortas was observed by Western Blot.The expression of eNOS protein inaortas was observed by immunohistochemical method.2. In vitro tests: Growth activityof HUVECs detected by MTT.The level of ROS in HUVECs detected by DCFH-DA fluorescence staining.The expression of eNOS mRNA and NOX4mRNA inHUVECs were observed by real time PCR.The expression of eNOS and NOX4protein in HUVECs were observed by Western Blot.Results:1. In vivo tests:①C ompared withthe control negative group, fastingblood glucose of model group was significantly increased(P<0.01).Compared with themodel group, after4weeks of administration,fasting blood glucose were significantlydecreased in sequyitol groups(P<0.05or P<0.01).②Compared with the controlnegative group, aortic relaxation response to acetylcholine of model group wassignificantly decreased (P<0.01).Compared with the model group,aortic relaxationresponse to acetylcholine of sequoyitol groups were significantly higher than themodel group(P<0.05or P<0.01).③I ntegerity of the aorticintima loss,smooth nusclehypertrophy,disorder and injury of the model group in HE staining,and sequoyitolgroups have different degrees of improvement.④MASSON staining showed that thecollagen fibers of aortic in the model group were increased, interstitial blue darklystained collagen fibers of aortic smooth muscle cells in sequoyitol groups weregradually reduced.⑤Compared with the control negative group, the levels of serumNO,T-AOC of model group were significantly decreased(P<0.01),the level of serumH2O2was significantly increased(P<0.01).Compared with the model group,the levelsof serum NO,T-AOC of sequoyitol groups were significantly increased(P<0.05orP<0.01),and the level of serum H2O2was significantly decreased(P<0.05orP<0.01).⑥C ompared with the control negative group, the expression of NOX4mRNA and NOX4protein in aortas of model group were significantlyincreased(P<0.01).Compared with the model group, sequoyitol dose-dependentdownregulation the expression of NOX4mRNA and NOX4protein inaortas(P<0.01).⑦Compared with the control negative group, the expression of eNOSmRNA and eNOS protein in aortas of model group were significantly decreased(P<0.01).Compared with the model group,sequoyitol dose-dependent upregulation the expression of eNOS mRNA and eNOS protein in aortas(P<0.01).2. In vitro tests:①MTT:The cell viability of glucose group was significantlydecreased(P<0.01).Compared with the glucose group, the cell viability of sequoyitolgroups were significantly increased(P<0.01).②C ompared with the glucose group,sequoyitol groups could inhibit ROS release (P<0.01).③Compared with the glucosegroup, sequoyitol dose-dependent downregulation the expression of NOX4mRNA andNOX4protein in HUVECs (P<0.01).④Compared with the glucose group, sequoyitoldose-dependent upregulation the expression of eNOS mRNA and eNOS protein inHUVECs (P<0.01).Conclusion:①Sequoyitol can significantly reduce fasting blood glucose.②Sequoyitolimprove aortic endothelium-derived diastolic function of type2diabetic rats.③Sequoyitol can significantly increase the levels of serum NO,T-AOC,decrease thelevel of serum H2O2.④Sequoyitol can improve the morphological changes in aortas oftype2diabetic rats.⑤Sequoyitol upregulate the expression of eNOS mRNA and eNOSprotein,downregulate the expression of NOX4mRNA and NOX4protein inaortas of type2diabetic rats.⑥Sequoyitol can increase cell viability of HUVECsexpose to glucose,inhibit ROS release to improve the injury of glucose toHUVECs.⑦Sequoyitolsignificantly upregulate the expression of eNOS mRNA andeNOS protein, downregulate the expression of NOX4mRNA and NOX4protein in HUVECs.