电磁辐射对大鼠睾丸P450scc mRNA表达及睾酮合成的影响和防护

Influence of Electromagnetic Irradiation on P450scc mRNA Expression in Rat Testis Tissues and Protective Effect of the Shield

目的:探讨电磁辐射对大鼠睾丸合成睾酮(T)的影响及其机制,评价铜丝网的防护效果。方法:采用Wistar雄性大鼠,随机分为对照组(n=60)、无屏蔽电磁辐照组(n=60)和铜丝网全身屏蔽辐射组(n=60),电磁辐照后分别取3、6、24、72h各时相点各组大鼠15只;采用放射免疫法(RIA)分别测定电磁辐照后3、6、24、72h及对照组血清T含量,反转录聚合酶链反应(RTPCR)测定各组睾丸组织中细胞色素P450胆固醇侧链裂解酶(P450scc)mRNA水平。结果:无屏蔽辐照组辐照后3h血清T含量和P450sccmRNA水平均明显低于对照组(分别较对照组降低83.9%,56.9%;P均<0.01),6h略有回升,但仍明显低于对照组(分别较对照组降低54.8%,27.3%;P均<0.01),24h恢复到正常水平,72h再次出现明显降低(分别较对照组降低60.1%,56.1%;P均<0.01);采用铜丝网全身屏蔽后,血清T和睾丸组织P450sccmRNA表达均未见明显变化。结论:电磁辐射能在转录水平影响睾丸间质细胞P450sccmRNA的表达,从而降低T的合成;铜丝网屏蔽具有较好的防护效果。

Objective: To study the influence of electromagnetic irradiation on cytochrome P450 cholestero side chain lyase (P450scc) in adult rat testis tissues and to assess the protective effect of the copper shield. Methods: Healthy male Wistar rats were randomized into a control group, an electromagnetic irradiation group and a wholly shielded group (with the copper shielding net). The electromagnetic irradiation group and the shielded group were set for 4 phases of 3, 6, 24 and 72 hours after irradiation, 15 rats for each phrase. The testosterone contents in the serum of the irradiated rats at 3, 6, 24 and 72 hours and in that of the controls were measured by radioimmunoassay(RIA), and so was the level of the P450scc mRNA in the testis tissues by semi-quantitative RT-PCR. And the effect of the copper shielding net on testosterone and P450scc mRNA was observed. Results: The contents of testosterone and the P450scc mRNA level in the irradiated group were significantly lower than in the control rats, decreased by (83.9)% and (56.9)%at 3 hours(P<(0.01)), (54.8)% and (27.3)% at 6 hours (P<(0.01)), restored to normal at 24 hours, but again reduced by (60.1)% and (56.1)% respectivly(P<(0.01)). While in the shielded group, no significant change was observed either in the testosterone of the serum or in the P450scc mRNA expression in the testis tissues. Conclusion: Electromagnetic irradiation may affect the transcription of P450scc in adult rat Leydig cells and thereby decrease the testosterone synthesis. Whole-body shielding with the copper net may achieve satisfactory effect. Natl J Androl,2005,11(4):269-271