丙酮酸乙酯对百草枯中毒小鼠肺损伤的保护作用

Protective effects of ethyl pyruvate treatment on lung injury in paraquat-intoxicated C57BL mice

目的:探讨百草枯(paraquat)对小鼠肺损伤的作用机制,及丙酮酸乙酯对肺损伤的保护作用。方法:C57BL小鼠腹腔注射百草枯(20mg/kg)诱导损伤(PI组);2h后腹腔注射丙酮酸乙酯(40mg/kg)。在损伤6、12、24h后,酶联免疫吸附法(ELISA)检测血清血浆肿瘤坏死因子-α(TNF-α)、白介素-1β(IL-1β)水平;24h后观察肺病理改变;免疫组织化学检测Caspase-3的蛋白表达。结果:PI组小鼠血清TNF-α和IL-1β水平在给予百草枯后迅速升高,约在6h达高峰,之后迅速下降。经丙酮酸乙酯治疗,血清TNF-α和IL-1β水平均低于PI组,且在6h差异显著(P<0.01)。结论:百草枯可引起小鼠细胞炎性因子TNF-α和IL-1β大量产生,TNF-α和IL-1β可能参与肺损伤过程;早期给予丙酮酸乙酯能降低TNF-α和IL-1β的释放,降低Caspase-3蛋白的表达,抑制细胞凋亡,可以减轻肺组织损伤。

Objective To investigate the mechanism of lung injury in paraquat-intoxicated C57BL mice, and the protective effects of ethyl pyruvate on lung injury. Methods Animals were randomly divided into 3 groups： control group （NS group）, paraquat-intoxicated group （PI group）, and PI followed by ethyl pyruvate （EP） treatment group （EP group）. The C57BL mice in PI group received intraperitoneal injection of 20 mg/kg paraquat （PI group）, and the C57BL mice in EP group treated with ethyl pyruvate （40 mg/kg, ip） 2 h after intraperitoneal injection of 20 mg/kg paraquat. 6, 12, 24 h after treatments, the mice in different groups were sacrificed respectively. The serum levels of TNF-a and IL-1β were measured by enzyme-linked immu-nosorbent assay （ELISA）. And immunohistochemitry assay was used to analyze the expression of Caspase-3. Results The result showed that the serum levels of TNF-a and IL-6 were rapidly induced by intraperitoneal injection of paraquat. It peaked at 6 h post treatment, and then decreased at 12 h. Comparing to PI group, the serum levels of TNF-a and IL-1β were significantly lower in EP group at 6 h post-treatment （P 〈 0.01 ）. Conclusions The serum levels of TNF-a and IL-6 were rapidly increased after exposure to paraquat, which suggested that they may play an important role in lung injury in paraquat-intoxicated C57BL mice. EP can inhibit the release of TNF-β and IL-1β, decrease the expression of Caspase-3 and reduce acute lung injury induced by paraquat in C57BL mice.