p,p’-DDE对青春期雄性大鼠的生殖毒性

Reproductive Toxicity of p,p'-DDE to Pubescent Male Rats

目的探讨p,p’-DDE染毒对青春期SD雄性大鼠生殖系统的毒性作用。方法将20只健康清洁级50日龄青春期雄性SD大鼠随机分为4组,分别为对照(玉米油)组和低(20 mg/kg)、中(60 mg/kg)、高(100 mg/kg)剂量p,p’-DDE染毒组,每组5只。采用腹腔注射方式进行染毒,注射容积为10 ml/kg,隔天1次,共进行10 d。第11天处死大鼠,称取睾丸、肝、肾、脾、肺组织重量,并计算脏器系数。采用TUNEL法检测大鼠睾丸细胞凋亡情况。采用实时荧光定量PCR(FQ-PCR)测定大鼠睾丸组织钙蛋白酶1(calpain-1)及兔抗半胱天冬氨酸蛋白酶-12(caspase-12)mRNA的表达水平。测定大鼠精子活力参数[精子密度(sperm concentration)、活动精子密度(motile sperm)、平均速率(average path velocity,VAP)、直线运动速率(straight line velocity,VSL)、曲线运动速率(curvilinear velocity,VCL)、精子头侧摆幅度(amplitude oflateral head displacement,ALH)、鞭打频率(beat cross frequency,BCF)、前向性(straightness,STR)、直线性(linearity,LIN)、摆动性(wobble,WOB)]和精子畸形率。结果与对照组比较,中、高剂量p,p’-DDE染毒组大鼠肝脏系数较高,而低、高剂量p,p’-DDE染毒组肾脏脏器系数较低,差异均有统计学意义(P<0.05)。各组大鼠睾丸、脾、肺组织脏器系数间比较,差异均无统计学意义。与对照组比较,低、中、高剂量p,p’-DDE染毒组大鼠睾丸组织细胞凋亡指数和精子畸形以及低、中剂量p,p’-DDE染毒组大鼠睾丸组织中calpain-1和caspase-12 mRNA表达水平均较高,差异有统计学意义(P<0.05),但高剂量组均无统计学上差异。且随着p,p’-DDE染毒剂量的升高,大鼠睾丸组织细胞凋亡指数以及睾丸组织中calpain-1和caspase-12mRNA表达水平均呈先升高后下降的趋势,精子畸形率呈上升趋势。与对照组比较,低、中剂量p,p’-DDE染毒组大鼠精子密度明显减少,中剂量p,p’-DDE染毒组大鼠精子曲线运动速率、精子头侧摆幅度、鞭打频率均下降,差异有统计学意义(P<0.05)。而高剂量p,p’-DDE染毒组大鼠精子的各指标变化不明显,差异无统计学意义。结论 p,p’-DDE可对青春期大鼠的生殖系统产生毒性作用。

Objectives To study the reproductive toxicity of p,p＇-DDE exposure to SD puberty male rats.Methods Twenty male SD rats were randomly divided into four groups（three exposed groups and one control group）,five in each.The rats were given different doses of p,p＇-DDE（0,20,60 and 100 mg/kg respectively） in corn oil,by intraperitoneal injection,every other day for ten days.After 10-day treatment,the rats were sacrificed and the testis were removed immediately and weighed;The method of TUNEL was used to investigate the effect of p,p＇-DDE on testis cells apoptosis.Real-time PCR were used to detect calpain-1 and caspase-12 mRNA.The sperm motility and the rate of deformed sperms were detected.Results Compared with the control group,the organ coefficients of liver increased significantly in the moderate and high p,p＇-DDE dose groups,and the organ coefficients of kidney increased significantly in the low and high p,p＇-DDE dose groups;the apoptotic index and rates of sperm malformation increased significantly in different p,p＇-DDE-treated groups,the mRNA levels of calpain-1 and caspase-12 in the low and moderate p,p＇-DDE dose groups were significantly higher（P0.05）,but there were no significant differences in the mRNA levels of calpain-1 and caspase-12 between the high dose of p,p＇-DDE group and control group（P0.05）.And with the increase of the p,p＇-DDE dose,the apoptotic index and the mRNA levels of calpain-1 and caspase-12 presented a trend of decreasing after increasing,and the rates of sperm malformation presented a trend of increasing.The sperm density significantly decreased in the moderate and high dose groups（P0.05）;Significant decreases in sperm motility parameters of motile sperm,VCL,ALH and BCF were seen in comparison with the control group（P0.05）.However there were no significant differences in all the indexes between the high dose of p,p＇-DDE group and control group（P0.05）.Conclusion p,p＇-DDE may have productive toxicity to the pubescent male rats.