Objective: To study the role of microbial-derived antioxidants (MA) based on the model of diquat-induced oxidative stress, endoplasmic reticulum stress, apoptosis and function in mice. Methods: 18 female C57BL/6 mice with body mass of 16~18 g were selected and randomly divided into 3 groups with 6 mice in each group. After 22 days of feeding, model and antioxidant group mice were intraperitoneally injected with diquat solution and control group were injected with same amount of isotonic saline. The content of free radical, MDA, antioxidant enzyme activity, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activity were detected according to the instructions of the kit. QRT-PCR was used to detect the expression of endoplasmic reticulum stress and apoptosis-related genes. One-way analysis of variance was used for data comparison between groups. Results: Hydrogen peroxide (H(2)O(2)) in the control group, model group and antioxidant group was (8.74 ± 1.38), (11.44 ± 1.01), (9.81 ± 0.98) mmol/g prot, respectively, and the difference between the groups was statistically significant (F = 7.640, P < 0.05). MDA content in the control, model and antioxidant group were (0.65 ± 0.07), (0.86 ± 0.18), (0.70 ± 0.05) nmol/mg prot, respectively, and the difference between the groups was statistically significant (F = 5.406, P <0.05). Aspartate aminotransferase (AST) activity in the model group (146.68 ± 4.29) U/gprot was significantly higher than control group (125.64 ± 15.69) U/gprot and antioxidant group (126.57 ± 1.82) U/gprot, F = 6.192, P < 0.05. Real-time quantitative PCR result showed that the relative expression of protein kinase R-like endoplasmic reticulum kinase (PERK) and activated transcription factor 6 (ATF6) genes in the model group was significantly higher than control group, which were 1.880 ± 0.442 and 1.800 ± 0.380, F = 7.702 and 10.815, and P < 0.05, respectively. Apoptosis-related gene expression results showed that the relative expression levels of caspase3 and caspase8 genes in the antioxidant group (1.136 ± 0.381 and 1.593 ± 0.407) was significantly lower than model group (1.572 ± 0.127 and 2.843 ± 0.973), (F = 12.800, 7.657, P < 0.05). Conclusion: Microbial-derived antioxidants can reduce diquat-induced liver oxidative stress, endoplasmic reticulum stress and hepatocyte apoptosis in mice, and thus improves liver function.
目的： 以diquat诱导的小鼠氧化应激为模型，研究微生物源性抗氧化剂（MA）对小鼠肝脏氧化应激、内质网应激、细胞凋亡和功能的影响。 方法： 选择体质量16～18 g的C57BL/6雌性小鼠18只，随机分为3组，每组6只。抗氧化剂组小鼠灌胃MA，对照组和模型组小鼠灌胃等量等渗盐水，饲养22 d后，模型组和抗氧化剂组腹腔注射diquat溶液，对照组小鼠注射等量等渗盐水，处理3h后处死小鼠采集肝组织。肝脏组织制成10%匀浆后，依据试剂盒说明书检测自由基含量、丙二醛（MDA）含量、抗氧化酶活性、天冬氨酸转氨酶（AST）和丙氨酸转氨酶（ALT）活性，用qRT-PCR检测内质网应激和细胞凋亡相关基因表达情况。肝脏组织制成10%匀浆后，依据试剂盒说明书检测自由基含量、丙二醛（MDA）含量、抗氧化酶活性、天冬氨酸转氨酶（AST）和丙氨酸转氨酶（ALT）活性，用qRT-PCR检测内质网应激和细胞凋亡相关基因表达情况。多组间数据比较采用单因素方差分析。 结果： 过氧化氢在对照组、模型组、抗氧化剂组分别为（8.74±1.38）、（11.44±1.01）、（9.81±0.98）mmol/g，组间比较差异有统计学意义（F = 7.640，P < 0.05）。对照组、模型组和抗氧化剂组MDA的含量分别为（0.65±0.07）、（0.86±0.18）、（0.70±0.05）nmol/mg，组间比较差异有统计学意义（F = 5.406，P < 0.05）。模型组AST活性为（146.68±4.29）U/g，显著高于对照组的（125.64±15.69）U/g与抗氧化剂组的（126.57±1.82）U/g，F = 6.192，P < 0.05。实时定量PCR结果显示，与对照组相比，模型组蛋白激酶R样内质网激酶（PERK）和活化转录因子6（ATF6）基因相对表达量显著升高，分别为1.880±0.442和1.800±0.380（F值分别为7.702、10.815，P值均< 0.05）；与模型组相比，抗氧化剂组PERK和ATF6基因相对表达量显著降低，分别为1.310±0.333、1.180±0.204（P值均< 0.05）。细胞凋亡相关基因表达结果显示，抗氧化剂组caspase3和caspase8基因相对表达量分别为1.136±0.381、1.593±0.407，与模型组的1.572±0.127和2.843±0.973相比，显著降低（F值分别为12.800、7.657，P值均< 0.05）。 结论： 微生物源性抗氧化剂减弱diquat诱导的小鼠肝脏氧化应激、内质网应激和肝细胞凋亡，改善肝脏功能。.
Keywords: Apoptosis; Endoplasmic reticulum stress; Liver injury; Micro-derived antioxidant; Oxidative stress.