[Reproductive toxicity of male rats exposed to two isomers of bromopropanes].

OBJECTIVE

To study the reproductive toxicity of male rats exposed to 1-bromopropane and 2-bromopropane and to explore the toxic mechanism of two isomers.

METHODS

18 SPF SD male rats were randomly divided into 3 groups of 6 each, respectively. The groups were exposed to corn oil, 1-BP (1 g/kg) and 2-BP (1 g/ kg) for 7 days by intraperitoneally injection. Trait of reproductive organs, sperm characteristics, testicular histological and apoptotic findings and the lipid peroxidation in the testicular and epididymal tissue were determined.

RESULTS

Results showed that treatment with bromopropanes induced reduction in sperm concentration and increments in abnormalities of sperm injuries to sperm quality. In addition, 1-BP increased GR activity (7. 42 +/- 2.98 vs. 4.25 +/- 1.18, P < 0.05) in testis, and SOD activity (91.87 +/- 3.93 vs. 80.59 +/- 9.92, P < 0.05) and MDA level (0.49 -/+ 0.20 vs. 0.39 +/- 0.08, P < 0.05) in epididymis. 2-BP decreased the GSH lever (6.35 +/- 1.86 vs. 10.89 +/- 3.69, P < 0.05) and increased the MDA level (0.42 +/- 0.07 vs. 0.24 +/- 0. 11, P < 0.05; 0.48 +/- 0.08 vs. 0.39 +/- 0.08, P < 0.05) in epididymis and testis, decreased GST ( 53.21 +/- 9.60 vs. 61.98 +/- 10.41, P < 0.05) and GR activity (2.48 +/- 1.21 vs. 7.75 +/- 8.56, P < 0.05) in epididymis. There were no histopathological changes in treatment with 1-BP rats, except that retained and elongated spermatids near basement membrane at the spermatogenesis cycle were found. Whereas, treatment with 2-BP induced vacuolation, degeneration and necrosis in seminiferous tubules. Paralleling with testicular lesion, treatment with 2-BP increased the total apoptotic cells per tubule, the percentage of apoptotic cells and apoptotic index significantly, comparing with control (17.72 +/- 4.59 vs. 5.92 +/- 1.05, P < 0.05; 0.34 +/- 0.14 vs. 0.10 +/- 0.02, P < 0.05; 6.64 +/- 3.40 vs. 0.59 +/- 0.20, P < 0.01). As compring with 1-BP group, exposed to 2-BP increased the percentages of TUNEL-positive tubules and apoptotic cellindex (0.34 +/- 0. 14 vs. 0.12 +/- 0. 03, P < 0.05; 6.64 +/- 3.40 vs. 0.76 +/- 0.21, P < 0.01). In addition, 2-BP group increased the proportion of apoptotic germ cells and the number of active caspase-3-positive cells per tubule, compared with 1-BP and control (P < 0.01, P < 0.01; P < 0.01, P < 0.01).

CONCLUSION

This study indicates that bromopropanes can cause reproductive disorder in male rats, the rats treatment with 2-BP had more toxicity than that with 1-BP, and it might have different toxic mechanism between two isomers.