RESUMEN
<p><b>OBJECTIVE</b>To explore the relationship between physical and biological effects of alternating magnetic field and study the influence of the magnetic field on the reproductive function of murine testes.</p><p><b>METHODS</b>Thirty ICR mice were randomized into 5 groups: normal control, X-ray radiation, weak magnetic field (1000 Hz), 1 h strong magnetic field and 2 h strong magnetic field (2000 Hz). The mice were sacrificed at 7 days after the exposure for the analysis of testicular sperm motility, observation of histopathological changes in the testis by HE staining and evaluation of the changes by modified Johnsen grade criteria.</p><p><b>RESULTS</b>The rates of sperm motility were (42.37 +/- 10.24)% in the normal control group, (39.00 +/- 12.35)% in the X-ray radiation group, (36.00 +/- 17.28)% in the weak magnetic field group, (10.72 +/- 5.67)% in the 1 h strong magnetic field group and (4.44 +/- 2.87)% in the 2 h strong magnetic field group, respectively. Johnsen's scores decreased and the testis damage increased in a dose- and time-dependent manner.</p><p><b>CONCLUSION</b>Magnetic field, either strong or weak, may damage the testis function by inducing injury to seminiferous tubules and Leydig cells, thickening of the basal membrane, derangement, exfoliation, massive apoptosis and necrosis of spermatogenic cells in the lumen, situation of the epididymis, and consequently the absence of sperm.</p>