Vascular smooth muscle cell senescence induced by reactive oxygen species and intervention effect of dehydroepiandrosterone / 中华老年医学杂志

Objective To observe the onset of vascular smooth muscle cell (VSMC) senescence induced by tert-butyl hydroperoxide (t-BHP) and the intervention effect of dehydroepiandrosterone (DHEA). Methods The VSMCs were divided into four groups: blank control group, t-BHP group (incubated with 80 μmol/L t-BHP for 72 h), 10 nmol/L DHEA intervention group (pretreated with 10 nmol/L DHEA 30 min before t-BHP) and 100 nmol/L DHEA intervention group (pretreated with 100nmol/L DHEA 30 min before t-BHP). Two ageing markers of ageing associated β-galactosidase activity and cell proliferation activity were adopted as main indexes. β-galactosidase activity was measured with immunocytochemical method and cell proliferation activity was measured with flowcytometry. Results After continuous treatment with 80 mmol/L t-BHP for 72 h, the ratios of G0/G1 phase cells and SA-β-galactosidase staining positive cells increased as compared with blank controlgroup [(89.4±3.4)% vs. (49.5±5.5)%, (3.5±1.2)% vs. (75.3±4.3)%], which indicated that VSMCs senescence were successfully induced by t-BHP. While the above changes were smaller in 100 nmol/L DHEA intervention group than in t-BHP group. Conclusions With ageing,accumulation of damage produced by reactive oxygen species may be an important mechanism causing the onset of VSMCs senescence. DHEA may be able to retard the progression of VSMCs senescence through antioxidant effect.

Effect of Estrogen Replacement Therapy on the Serum Nitric Oxide and Endothelin-1 Level of Ovariectomized Rats / 中国医师杂志

Objective To investigate the effects of estrogen replacement therapy on the serum nitric oxide and endothelin-1 level of ovariectomized rat.Methods The ovariectomized animal model and estrogen replacement therapy rat were established,thirty female rats were randomly divided into three groups:group A,ovariectomy;group B,ovariectomy plus estrogen replacement therapy;group C,sham-ovariectomy.The rats were killed after two months.The serum nitric oxide and endothelin-1 level were determined.Results In group A,the serum nitric oxide level was lower as compared with group C,but the serum endothelin-1 level was higher than those in group C.In group B,the serum nitric oxide level was higher and the serum endothelin-1 level was lower than those in group A.Conclusions Estrogen could modulate the productions of the nitric oxide and the endothelin-1 in the vascular endotheliocytes and improve the function of the vascular endothelial cells,which may be a bases of the benificial effect of estrogen in the prevention of atherosclerosis.