姜黄素通过抑制内质网应激和JNK通路过度活化减轻小鼠肺缺血再灌注损伤

 目的:探讨姜黄素（curcumin,Cur）是否通过抑制内质网应激和c-Jun氨基末端激酶(JNK)通路过度活化来减轻小鼠肺缺血再灌注(I/R)损伤。方法:采用C57BL/6J小鼠左侧肺原位I/R损伤模型。实验随机分为6组（每组10只），包括假手术组（sham组）、I/R组、DMSO组（I/R+DMSO组）和Cur组（I/R+Cur低、中、高剂量组）。实验结束后处死小鼠，留取左肺，检测肺湿干重比（W/D）和总肺水含量（TLW）；光镜、电镜观察肺组织形态结构变化，并进行肺组织损伤评估（IQA）；RT-PCR检测JNK和葡萄糖调节蛋白78（GRP78）的mRNA表达；Western blotting检测磷酸化JNK（p-JNK）和GRP78的蛋白表达；原位缺口末端标记法（TUNEL法）检测肺细胞凋亡指数（AI）。结果:与sham组相比，I/R组和DMSO组W/D、TLW、IQA及AI均明显升高（P<0.01），JNK、GRP78 mRNA和p-JNK、GRP78 蛋白表达量上升（P<0.01），光镜、电镜均显示肺组织结构出现明显损伤性变化。I/R组与DMSO组相比，上述各指标无显著差异（P>0.05）。与I/R组和DMSO组相比，I/R+Cur低、中、高剂量组各组GRP78 mRNA和蛋白表达量无明显变化（P>0.05），W/D、TLW、IQA及AI下降（P<0.05或P<0.01）且肺组织损伤减轻，JNK mRNA和p-JNK蛋白质表达量亦下降，以I/R+Cur高剂量组下降最为明显（P<0.01）。结论: 缺血/再灌注引发肺组织细胞发生过度的内质网应激，损伤肺组织。Cur能减轻肺缺血/再灌注损伤，其机制可能与抑制JNK信号通路的过度活化有关。

Curcumin attenuates lung ischemia-reperfusion injury in mice through inhibiting JNK pathway and excessive endoplasmic reticulum stress

AIM: To investigate the role of curcumin (Cur) in attenuating lung ischemia-reperfusion (I/R) injury by inhibiting c-Jun N-terminal kinase(JNK) pathway and excessive endoplasmic reticulum stress (ERS) in mice. METHODS: Mouse model of lung I/R injury in situ was established in the left lung in vivo. Sixty mice were randomly divided into 6 groups (n=10 in each group), including sham group, I/R group, dimethyl sulfoxide solvent control group (I/R+DMSO group) and curcumin groups (I/R+ low, medium or high dose of Cur group). Left lung tissue was isolated after the experiment. The ratio of wet lung weight to dry lung weight (W/D), and total lung water content (TLW) were measured. The histological structure and ultrastructure of the left lung were observed under light and electron microscopes, and scored by alveolar damage index of quantitative assessment (IQA). The mRNA expression and protein levels of JNK and GRP78 were measured by RT-PCR and Western blotting. Apoptotic cells in the lung tissue were determined by TUNEL method. RESULTS: Compared with sham group, all indexes above in I/R group and DMSO group were significantly increased. No significant difference of all indexes between I/R group and DMSO group was observed. Compared with DMSO group, the indexes above in low, medium and high doses of Cur groups were decreased, especially in high dose of Cur group, but the expression level of GRP78 had no statistical difference. CONCLUSION: I/R induces excessive ERS in the lung tissue and results in lung injury. Cur has a protective effect on lung against I/R injury, which may be related to inhibition of apoptosis mediated by JNK pathway in ERS.