L-半胱氨酸对慢性间歇性低氧大鼠血压和交感神经活动的影响

Effects of L-cysteine on blood pressure and sympathetic nerve activity in rats with chronic intermittent hypoxia

目的探讨L-半胱氨酸(L-cys)增加内源性H_(2)S对间歇性低氧引起的大鼠高血压的影响及机制。方法将雄性SD大鼠随机分为正常氧(Control)组、慢性间歇性低氧(CIH)组、正常氧L-cys干预(Control+L-cys)组和慢性间歇性低氧L-cys干预(CIH+L-cys)组。CIH组和CIH+L-cys组大鼠放入低氧仓进行间歇性低氧处理,每天8 h,连续15 d。L-cys干预组每天给予L-cys(10 mg/kg)灌胃。用无创套尾法测大鼠的尾动脉收缩压(SBP),PowerLab数据采集分析处理系统在体记录大鼠肾交感神经活动(RSNA),ELISA法测量血浆中去甲肾上腺素(NE)、H_(2)S含量和CSE、CBS活性。结果与Control组相比,间歇性低氧15 d后,CIH组大鼠SBP、RSNA,血浆中NE水平较升高,而血浆中H_(2)S水平降低;应用L-cys可增加CIH大鼠血浆中H_(2)S水平,显著抑制间歇性低氧引起的血压升高和交感神经活动过度激活。结论L-cys可能通过增加内源性H_(2)S改善间歇性低氧引起的高血压。

Objective To investigate the effect and mechanism of L-cysteine(L-cys)increasing endogenous H_(2)S on hypertension induced by intermittent hypoxia in rats.Methods Male Sprague-Dawley rats were randomly divided into normal oxygen(Control)group,chronic intermittent hypoxia(CIH)group,Control+L-cys group and CIH+L-cys group.The rats in CIH group and CIH+L-cys group were exposed to 15 d intermittent hypoxia,8 h daily.In L-cys treatment group,the rats were given L-cys(10 mg/kg)each day by the oral administration.Noninvasive measurement of tail artery systolic blood pressure(SBP)was measured by the tail cuff system.The renal sympathetic nerve activity(RSNA)renal sympathetic nerve activity(RSNA)were recorded in vivo on a PowerLab data acquisition system.The plasma concentrations of norepinephrine(NE)and H_(2)S,activity of cystahionine-β-synthase(CBS)and cystahionine-γ-lyase(CSE)were measured by ELISA kits.Results Systolic blood pressure of tail artery significantly increased after CIH exposure,but did not change after normoxia exposure.RSNA and plasma concentrations of NE were also significantly higher in CIH rats than in control rats.The plasma level of H_(2)S in CIH rats were significantly decreased than those in control rats。L-cys increased the level of H_(2)S of CIH rats,and significantly inhibited the increase of blood pressure and excessive activation of sympathetic nerve activity induced by intermittent hypoxia.Conclusion L-cys can improve intermittent hypoxia induced-hypertension in rats by increasing endogenous H_(2)S.