小檗碱与育亨宾对脓毒症小鼠脾细胞凋亡的影响及其机制研究

 目的:探讨小檗碱与育亨宾对脓毒症小鼠脾细胞凋亡的影响及其作用机制。方法: 采用盲肠结扎穿孔（CLP）构建小鼠脓毒症模型，分为假手术（sham）组、CLP组、CLP+小檗碱组、CLP+育亨宾组、CLP+小檗碱与育亨宾合剂组。CLP术后2 h灌胃给予相应药物，20 h后取脾脏，用TUNEL和流式细胞术检测小鼠脾细胞凋亡，酶荧光法检测caspase-3、caspase-8和caspase-9的活性变化，Western blotting检测凋亡相关蛋白Fas、Bim、Bcl-2和Bax的表达。结果: (1) CLP组脾脏TUNEL阳性细胞百分率显著高于sham组（P＜0.05），CLP+育亨宾与小檗碱合剂组、CLP+育亨宾组凋亡细胞百分率显著低于CLP组（P＜0.05）。(2) 流式细胞仪检测显示CLP组凋亡的脾细胞及T淋巴细胞明显多于sham组(P＜0.05)，CLP+育亨宾与小檗碱合剂组、CLP+育亨宾组凋亡的脾细胞及T淋巴细胞明显少于CLP组 (P＜0.05) 。(3) CLP+育亨宾与小檗碱合剂组、CLP+育亨宾组脾细胞caspase-3、caspase-8、caspase-9的活性均低于CLP组(P＜0.05)；而CLP+小檗碱组脾细胞caspase-9活性也低于CLP组 (P＜0.05)。(4) CLP+育亨宾与小檗碱合剂组胞浆Fas、Bim、Bax表达均低于CLP组，CLP+育亨宾组胞浆Fas表达低于CLP组，CLP+小檗碱治疗组胞浆Bim、线粒体Bax表达均低于CLP组。结论: (1) 小檗碱与育亨宾合用可通过阻断内、外源性凋亡途径抑制脓毒症小鼠脾细胞凋亡，特别是T淋巴细胞凋亡。(2) 育亨宾主要通过抑制Fas的表达、进而阻断内、外源性凋亡途径减少脓毒症诱导的脾细胞凋亡。(3) 小檗碱可抑制脓毒症小鼠脾细胞线粒体凋亡途径，但对脓毒症小鼠脾细胞凋亡的抑制作用并不明显。

Effects of berberine and yohimbine on splenocyte apoptosis in septic mice

AIM: To observe the effects of berberine and yohimbine on splenocyte apoptosis in septic mice and underlying mechanisms. METHODS: The mice were subjected to cecal ligature and puncture (CLP). The drugs or vehicle were given intragastrically 2 h after the surgery according to the following 5 groups: sham, CLP, CLP+berberine, CLP+yohimbine, and CLP+berberine+yohimbine. The apoptosis of splenocytes stained by TUNEL was observed under laser scanning confocal microscope 20 h after CLP. The splenic lymphocytes were isolated and observed using flow cytometry. The activities of caspase-3, caspase-8 and caspase-9 in splenic lymphocytes were detected, and the expression of Fas, Bim, Bcl-2 and Bax in the splenocytes was also determined by Western blotting. RESULTS: The TUNEL staining showed that the apoptotic rate of the splenocytes in septic mice 20 h after CLP was significantly higher than that in sham  and CLP+yohimbine groups (P＜0.05). Compared with CLP group, the proportion of apoptotic cells was decreased in septic mice in CLP+berberine+yohimbine and CLP+yohimbine groups (P＜0.05). Flow cytometry analysis demonstrated the similar results in the apoptosis of splenocytes and T lymphocytes. However, only yohimbine treatment reduced the apoptosis of B lymphocytes in the spleen of sepsis-challenged mice. Compared with CLP group, caspase-9 activity was significantly reduced in CLP+berberine group (P＜0.05), the activities of caspase-3, caspase-8 and caspase-9 were all statistically reduced (P＜0.05) in CLP+yohimbine group and CLP+yohimbine+berberine group. CLP significantly increased the expression of cytosolic Fas, Bim and mitochondrial Bax in the splenocytes, and decreased Bcl-2 expression compared with sham group. Compared with CLP group, the expression of cytosolic Bim and mitochondrial Bax in CLP+berberine group were reduced (P＜0.05). Fas expression decreased only in CLP+yohimbine group (P＜0.05). Berberine combined with yohimbine reduced the expression of cytosolic Fas, Bim and mitochondrial Bax in the septic mouse splenocytes (P＜0.05).CONCLUSION: Yohimbine reduces sepsis-induced splenic lymphocyte apoptosis in mice by inhibiting Fas expression and in turn blocking both extrinsic and intrinsic apoptosis pathways. Berberine reduces Bim expression and inhibits caspase-9 activation, but not caspase-3 activation and apoptosis in the septic mouse splenocytes. Berberine combined with yohimbine reduces splenocyte apoptosis in the septic mice by inhibiting both extrinsic and intrinsic apoptotic pathways.