RESUMEN
To investigate the comparative effects of aminoglycosides and fluoroquinolones on testis structure and serum testosterone hormone level in rats. Forty male Wister rats were randomly divided into control [n=10] and experimental [n=30] groups. The experimental groups were subdivided into three groups of ten. Each received 5 mg/kg [IP] Gentamicin, 40mg/kg [IP] Streptomycin and 72mg/kg [IP] Ofloxacin daily for 14 days, respectively; however, the control group just received vehicle [IP]. In the fourteenth day, 5cc blood was collected for testosterone hormone then rats were killed and testis tissues were also prepared for light and electron microscopic study. Depletion of germ cells, germinal cells necrosis, especially in spermatogonia, and Leydig cells had an abnormal fibroblast-like appearance. Abnormal space between neighbour sertoli cells, mitochondria were lost cristae and vacuolated [none energized], lyzosome seen more in cytoplasm of sertoli cells and Veins congestion were seen in gentamicin and ofloxacin groups. These side effects were seen fewer in Streptomycin group. Gentamicin, Streptomycin and Ofloxacin have negative effects on testis architecture and germinal cells damages in rats. However, these side effects are seen less in the Streptomycin group. Therefore, it is recommended that usage of this drug have fewer side effects on male fertility