砷和氟对大鼠睾丸组织caspase-3和caspase-9表达的影响

Effects of arsenic and fluoride on expression of caspase-3 and caspase-9 in testicular tissue of rats

目的研究慢性砷染毒、氟染毒及联合染毒大鼠睾丸组织中caspase-3、caspase-9表达的变化。方法将40只健康清洁级雄性SD大鼠随机分为4组,分别为对照(普通饲料)组、砷染毒(高砷饲料,含砷量为10.000 mg/kg)组、氟染毒(高氟饲料,含氟量为16.844 mg/kg)组和砷氟联合染毒(高砷高氟饲料,含砷量为10.000 mg/kg,含氟量为16.844 mg/kg)组,每组10只。采用自由进食饲料方式连续染毒12周。采用TUNEL染色法测定生精小管细胞的凋亡率;采用免疫组化法测定睾丸间质细胞caspase-3、caspase-9的阳性表达水平。结果与对照组比较,各染毒组大鼠生精小管生精细胞的凋亡率均较高,差异有统计学意义(P<0.05)。与对照组比较,各染毒组大鼠间质细胞caspase-3、caspase-9的阳性表达水平均较高,差异有统计学意义(P<0.05)。且砷氟联合染毒组大鼠间质细胞caspase-3、caspase-9的阳性表达水平高于氟染毒组高砷染毒组,差异均有统计学意义(P<0.05)。结论砷及氟联合染毒所致大鼠睾丸组织的损伤及凋亡可能通过激活caspase-3或caspase-9等途径实现。

Objective To observe the expression changes of caspase-3 and caspase-9 in testis tissue of rats under the condition of chronically exposed to arsenic, fluoride singly and in combination. Methods Forty healthy clean level male SD rats were randomly divided into four groups,10 in each, the control group（normal feed）,arsenic exposure group（treated with high arsenic fodder of 10.000 mg/kg body weight）,fluoride exposure group（treated with high fluoride fodder of 16.844 mg/kg body weight） and arsenic plus fluoride group（treated with high arsenic fodder of 10.000 mg/kg body weight and high fluoride fodder of 16.844 mg/kg body weight）,which were treated for 120 consecutive days. The apoptosis rate of born seminiferous tubule cells were evaluated by TUNEL staining method. The positive expression level of caspase-3 and caspase-9 in leydig cells were evaluated by immunohistochemical method. Results Compared with the control group,the apoptosis rate of the born seminiferous tubule born sperm cells in each exposed groups were significantly higher（P〈0.05） and the positive expression levels of caspase-3 and caspase-9 in leydig cells in each exposed group were significantly higher（P〈0.05）. The positive expression level of caspase-3 and caspase-9 in leydig cells in arsenic-fluoride exposure group was higher than that in arsenic and fluoride single exposure group,with significant difference（P〈0.05）. Conclusion Joint exposure to arsenic and fluoride may cause injury and apoptosis in testicular tissue of rats by activating caspase-3 or caspase-9.