RESUMEN
Objective 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.
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0.05).Conclusions:There was no difference in terms of both effect and toxicity among the three regimens. All of them were effective and could be well tolerated by advanced colorectal cancer patients.