The Inhibitory Effects Of Endogenous Glucocorticoid On Vascular Inflammation

Objective:Diabetes is a Metabolic disease which usually is accompanied with cardivascular complication. Diabetes causes cardivascular disease chiefly through endothelial dysfunction. Oxidative stress and inflammation are considered to be important mechanisms for endothelial dysfunction.Numerous evidences have indicated that endogenous glccocorticoid has anti-inflammatory effect by enhancing HDAC activity which leads to decreased expression of multiple inflammatory genes that are regulated by proinflamatory factors, such as NF-kappaB. In the present review, oxidative stress can cause reduction in HDAC activity in lung and switch off the anti-inflammatory effect of exogenous glccocorticoid.So,we think that reduction in HDAC activity, secondary to oxidative stress,may also inhibit the effect of endogenous glccocorticoid.This study was designed to test the hypothesis that physiological level glccocorticoid plays an important role in vascular inflammation and how does oxidative stress inhibit the effect of endogenous glccocorticoid.Methods:1. The level of IL-1β,IL-6,IL-10,NF-κB,and HDAC of thoracic aorta in rats (180-220g) with pretreated with glccocorticoid receptor antagonist RU486,HADC inhibitor TSA,or adrenalectomy are tested by ELISA.2. Choose C57/B6 mice of 6-8 weekes old.Intraperitoneal inject STZ to induce diabetic mice.Diabetic mice are divided into tow groups:1 DM-2,4,8,and 12 weeks;2 DM-tempol,allopurinol,apocynin,and combined. The level of glccocorticoid is tested by ELISA. The levels of IL-6,IFN-γ,TNF-α,and MCP-1 are tested by FCM.The activities of NF-κB and HDAC of thoracic aorta are tested by ELISA.3. Use 8-week-old diabetic mice,8-week-old normal mice; 12-week-old diabetic mice,12-week-old normal mice; diabetic mice respectively pretreated with tempol,allopurinol,apocynin,and combined, 10-week-old diabetic mice. Use their thoracic aorta to make paraffin sections and HE stain.4. Vascular endothelial cells were isolated and cultured from mouse aorta and identified by morphology and immunohistochemistry.EC in passage 3-5 was used for this study and respectively pretreated with LPS,hydrocortisone,TSA,and so on.The levels of IL-1β,IL-6,IL-10,NF-κB,and HDAC are tested by ELISA.Results:1. Respectively pretreated with RU486,TSA,and adrenalectomy markedly enhanced effects of LPS on the expression of IL-1β,IL-6,IL-10,and NF-κB of rat thoracic aortas.For HDAC, preteated with TSA can inhibit its activity,but RU486 or adrenalectomy has no effect.2. The expression of glccocorticoid, IL-6,IFN-γ,TNF-α,MCP-1,and NF-κB of diabetic mice is increased with time(DM-2,4,8,12 weeks),but HDAC activity is decreased.3. Respectively pretreated with tempol,allopurinol,apocynin,and combined has different effects on the expression of IL-6,IFN-γ,TNF- α,MCP-1 of diabetic mice.All of the trement can reduce NF-κB activity,but enhance HDAC activity.Conlusion:1. The results indicated that endogenous glccocorticoid has anti-inflammatory effect on vascular inflammation induced by LPS in rats2. Oxidative stress depresses the anti-inflammatory effect of endogenous glccocorticoid through inhibiting vascular HDAC activity in diabetic mice.