摘要目的：探讨亚慢性砷中毒对大鼠睾丸间质细胞caspase-3表达及血清中睾酮含量的影响。方法将40只健康成年清洁级SD雄性大鼠按体质量(160~220 g）采用随机数字表法分为4组,分别为对照组(饮用蒸馏水）和2.0、12.0、60.0 mg/L三氧化二砷(As2O3）染毒组(低、中、高剂量组）,每组10只,采用自由饮水方式进行染毒,连续染毒14周。采集各组大鼠心脏血,采用酶联免疫吸附(ELISA）法检测血清中睾酮的浓度；采集各组大鼠睾丸组织,免疫组织化学法对睾丸间质细胞caspase-3表达进行定位和半定量检测,Biomias图像分析软件测定caspase-3阳性细胞平均灰度值。结果各组间大鼠血清中睾酮含量比较差异有统计学意义(F=37.99, P<0.05）。其中,中、高剂量组大鼠血清中睾酮含量[(1.6946±0.2554）、(1.3505±0.2819）ng/L]均低于对照组[(3.0823±0.6530）ng/L,P均<0.05]。对照组,低、中、高剂量组大鼠睾丸caspase-3阳性间质细胞计数分别为(8.10±1.91）、(9.80±2.15）、(10.00±1.83）、(10.90±2.38）个/视野,各组间比较差异有统计学意义(F=3.17,P<0.05）,中、高剂量组均高于对照组(P均<0.05）。对照组,低、中、高剂量组caspase-3阳性细胞平均灰度值分别为135.10±6.89、130.00±3.30、117.10±4.28、113.10±5.38,各组间比较差异有统计学意义(F=41.09,P<0.05）,中、高剂量组均低于对照组(P均<0.05）。结论 As2O3对雄性生殖细胞毒性机制之一可能是通过上调SD大鼠睾丸间质细胞caspase-3的表达,启动细胞凋亡的信号传递途径,诱发睾丸间质细胞凋亡增加,睾酮含量下降,对生殖功能造成损伤。

abstractsObjective To investigate the effects of subchronic arsenic exposure on caspase-3 expression in Leydig cells and serum testosterone level in rats. Methods Forty SD rats were divided into four groups based on body mass (160-220 g) by random number table, 10 in each group and treated with As2O3 through drinking water at the doses of 0.0 (distilled water), 2.0, 12.0 and 60.0 mg/L for 14 weeks. Blood sample from heart was collected, serum testosterone was measured by enzyme linked immunosorbent assay (ELISA); the testicular tissue of rats was taken, the expression of caspase-3 was assayed by immunohistochemical staining, and its average gray value was analyzed with image analysis software (Biomias). Results There were statistically significant differences of the serum testosterone levels between groups (F= 37.99, all P< 0.05). Compared with the control group [(3.082 3 ± 0.653 0) ng/L], serum testosterone levels in middle-dose and high-dose groups [(1.694 6 ± 0.255 4), (1.350 5 ± 0.281 9)ng/L] were significantly lower (all P< 0.05). The numbers of positive cells of caspase-3 were 8.10 ± 1.91, 9.80 ± 2.15,10.00 ± 1.83 and 10.90 ± 2.38 in each vision in the 4 groups, there were statistically significant differences between groups (F=3.17, all P<0.05), compared with the control group , the middle-dose and high-dose groups were significantly higher (all P<0.05);the average gray values of caspase-3 were 135.10 ± 6.89, 130.00 ± 3.30, 117.10 ± 4.28, and 113.10 ± 5.38, there were statistically significant differences between groups (F = 41.09, P < 0.05), compared with the control group, the middle-and high-dose groups were decreased (all P<0.05). Conclusions One possible mechanism of As2O3 on male germ cell toxicity may be through up-regulation of the expression of caspase-3 in Leydig cells of SD rats and initiating the pathway of the apoptosis signal, which can lead to increased apoptosis of Leydig cells, decreased concentrations of testosterone, and damaged reproductive function in rats.