褪黑素对丙烯酰胺致睾丸毒性保护作用的机制（英文）

Protective Roles of Melatonin against Acrylamide-induced Testicular Toxicity in Rats

【目的】探讨褪黑素(MT)对丙烯酰胺(AA)诱发睾丸毒性的改善作用及机制。【方法】动物随机分为3组:对照组,AA染毒组和AA+MT治疗组,每组各12只大鼠。AA染毒的动物连续4周每日灌胃AA(15 mg/kg)。从染毒3周后开始,治疗组动物先每日腹腔注射MT 10 mg/kg(连续1周),30 min后再进行AA染毒。对照组动物仅注射同等剂量的生理盐水。随后分别进行线粒体膜电位、TUNEL、免疫印迹和电镜检测。【结果】研究结果表明AA可使睾丸组织线粒体膜电位下降(P<0.05),且MT可令其恢复(P<0.05)。和对照组相比,MT可下调睾丸组织中Bax的表达;上调Bcl-2的表达。TUNEL结果进一步证实MT可减缓解睾丸组织中细胞凋亡现象。免疫印迹结果表明AA染毒组Bcl-2/Bax和Bcl-xL/Bak的比值较对照组降低(P皆<0.05),而MT治疗组中它们的比值升高(P皆<0.05)。AA染毒组中Cyt-c,Casp-3,p53和NF-κB的表达水平较对照组明显升高(P皆<0.05),较MT治疗组明显下降(P皆<0.05)。电镜结果证实MT可减轻AA造成的睾丸曲细精管中线粒体结构受损。【结论】MT可能通过和线粒体通路相关的抗凋亡功能,从而缓解AA造成的睾丸毒性。

[Objective ] The present study aimed to determine the protective role of Melatonin （MT） against Acrylamide （AA）- induced testicular toxicity and the potential molecular mechanism. [ Methods ] The animals were randomly divided into three groups, the control group （n = 12）, the AA group （n = 12） and the AA＋MT group （n = 12）. The rats in the AA and AA ＋ MT group were gavaged with AA at a dose of 15 mg/（kg-day） for 4 consecutive weeks. After 3 weeks of AA treatment, MT was intraperitoneally injected 30 minutes before AA treatment at 10 mg/（kg, day） for 1 week in the AA ＋ MT rats. Subsequently, the mitochondrial membrane potential measurement, TUNEL assay, Western blot and electron microscopic techniques were applied in the present study. [Results] The results showed that AA could decrease the testis mitochondrial membrane potential （P 〈 0.05） which could be recovered by MT （P 〈 0.05）. Moreover, MT induced down-regulation of Bax expression and up-regulation of Bcl-2 expression in the testis, compared with AA rats. The amelioration of testicular apoptosis was further confirmed by the TUNEL labeling. Western blot results suggested that the decreased ratios of Bcl-2/Bax and Bcl-xL/Bak in the AA group （both P 〈 0.05） could be recovered by MT treatment （both P 〈 0.05）. The levels of Cyt-c, Casp-3, p53 and NF-κB in AA group were markedly elevated compared with the control （all P 〈 0.05）, and reduced in MT treatment group （all P 〈 0.05）. MT could relieve abnormal mitochondrial structures in the seminiferous tubule in the electron microscopic level. [ Conclusion ] MT may exert productive effect through its anti-apoptotic properties associated with mitochondria.