Psychological stress reduces the plasma NO level and NO-regulating protein expression in the vascular en-dothelial cells of rats / 医学研究生学报

ABSTRACT

[Abstract ] Objective The mechanism of psychological stressi-nduced damage to vascular endothelial cells (VEC) is not yet clear.This study was to investigate the impact of psychological stress on the NO level and NO-related regulatory protein expression in the plasma of rat models of psychological stress-induced VEC injury. Methods Twenty male SD rats were equally randomized into a con-trol group and a model group, the former raised together, with water regularly fed at 900 and 2100 hours for 10 minutes a day, while the latter raised alone, with water regularly fed at the same hours for 10 minutes a day for the first 7 days and then with water or an empty bottle at the same hours for 10 minutes a day according to the random table.Ninety days later,all the rats were intraperitoneally injected with normal saline at 0.2 ml per 100 g body weight twice a day.Then the behaviors of the animals were observed by open field tests, the contents of cortisol (COR),adrenaline (Adr), and endothelin-1 (ET-1) in the plasma measured by ELISA, the NO level detected by the nitrate reductase method, and the expression of NO-related regulatory proteins in VECs determined by LC-ESI-MS. Results Com-pared with the control group, the model rats showed significant increases in the vertical score (7.00 ±0.70 vs 11.28 ±1.79), horizontal score (37.60 ±4.500 vs 56.25 ±1.71), and total score (44.50 ±5.50 vs 67.25 ±2.98) (P<0.01) as well as in the levels of COR ([65.28 ±2.21] vs [83.85 ±1.95] ng/mL ) and Adr ([3.85 ±0.35] vs [15.14 ±3.97] pg/mL) (P<0.01), but a remarkable de-with vacuoles in the VECs in the model group and structural integrity, ridge clarity, and tight pack in the VEC mitochondria in the con-trol. Conclusion Psychological stress induced by empty bottle stimulation can reduce the NO level and the expression of NO-related regulatory proteins in the plasma, which may cause both functional and structural damages to VECs.