金属硫蛋白对镍铬染毒小鼠睾丸损伤保护作用

目的 探讨金属硫蛋白（MT）对镍铬联合染毒小鼠睾丸损伤的保护作用。方法 50只昆明种雄性小鼠随机分为5组：对照组，镍铬染毒组，低、中、高剂量MT组。对照组灌胃生理盐水，镍铬染毒组及MT组灌胃（NiSO₄ 1.0、K₂Cr₂O₇ 0.5 mg/kg混合溶液），低、中、高剂量MT组分别灌胃5.0、10.0、15.0 mg/kg MT溶液，每日1次，连续20 d；实验结束处死动物检测睾丸、附睾脏器系数，睾丸病理形态学、精子质量观察，试剂盒检测睾丸细胞凋亡、超氧化物岐化酶（SOD）、丙二醛（MDA）含量。结果 与对照组比较，镍铬染毒组小鼠睾丸、附睾脏器系数[分别为（0.73±0.10）%、（0.24±0.07%）减小，睾丸结构受损，精子数[（9.96±0.67）10⁷个/g附睾]及活动度[（39.23±4.87）%]下降，睾丸细胞凋亡率[（20.65±1.68）%]及MDA含量[（112.51±7.21）nmol/g prot]升高，SOD活力[（118.17±12.28）U/g prot]下降（P<0.05）；与镍铬染毒组比较，高剂量MT组小鼠睾丸、附睾脏器系数[分别为（1.25±0.14）%、（0.39±0.11）%]明显升高，精子数[（17.79±0.86）10⁷个/g附睾]及活动度[（70.48±6.24）%]上升，睾丸细胞凋亡率[（9.02±1.14）%]及MDA含量[（25.55±5.81）nmol/g prot]下降，SOD活力[（313.19±15.37）U/g prot]升高（P<0.05）。结论 镍铬联合染毒对小鼠睾丸有损伤作用，一定剂量的MT对其受损的睾丸有修复作用，其作用机制可能与抗氧化作用有关。

Protective effect of metallothionein on testicular injury in nickel-chromium exposed mice

Objective To investigate the protective effect of metallothionein(MT) on testicular injury in mice with nickel-chromium(NiCr)-combined exposure.Methods Fifty Kunming mice were randomly divided into five groups based on weight:control group, NiCr-combined exposure group, low, moderate, and high dose MT group.The mice in solvent control group were given normal saline intragastrically.The mice in NiCr-combined exposure group were given 1.0 mg/kg·bW nickel sulfate and 0.5 mg/kg·bW potassium dichromate solution.The mice in low, moderate and high dose MT groups were given 5.0, 10.0 and 15.0 mg/kg·bW MT solution intragastrically.The mice in NiCr-combined exposure group and MT groups were given nickel sulfate-potassium dichromate combined solution intragastically in the morning, and then were given MT solution intragastically in the afternoon.All the mice had the intragastic administration once a day for 20 days.At the end of the treatments, all mice were sacrificed and their blood samples were collected, and the testis and epididymis viscera coefficients were measured.The testicular pathological morphology and sperm quality were observed.Apoptosis of testicular cells and content of superoxide dismutase(SOD) and malondialdehyde(MDA) were detected.Results The testis and epididymis viscera coefficients(0.73%, 0.24%) were reduced in the mice with NiCr-combined exposure, but the mice in moderate and high dose MT groccp showed repairment of impaired testicular structure and increased testis viscera coefficient(1.13%, 1.25%) and epididymis viscera coefficient(0.37%, 0.39%)(P<0.05 for all).Compared with NiCr-combined exposure group, the mice in moderate and high dose MT group had improved sperm counts(17.25×10⁷/g, 17.79×10⁷/g) and energy(68.25%, 70.48%), reduced ratio of abnormal sperms(6.55%, 4.77%), improved testis SOD activity(298.26, 313.19 U/gProt), and reduced apoptosis rate(9.57%, 9.02%) and MDA content(28.16%, 25.55%)(P<0.05 for all).Conclusion MT has protective effect on testicular injury in mice with nickel-chromium-combined exposure and the mechanism of the protective effect may be correlated with improvement of enzyme activity, reduction of testicular cells apoptosis, and enhancement of antioxidant effect.