Gentamicin can pass through the placenta. This antibiotic also enters breast milk, but its absorption in the intestine is insignificant, so that it could be only found in half of the infants’ blood. In the present study, it is attempted to experimentally evaluate the toxic effect of gentamicin on the kidneys of newborn mice in breastfeeding. This study was performed on 20 female Balb/c pregnant mice weighing 30 to 35 g. The female pregnant mice were randomly divided to two groups of 10. The lactating mothers were intraperitoneally injected with gentamicin at 200 mg/kg every other day sequentially, and the normal group was injected with normal saline at the same volume. Blod samples were collected from the heart of the newborns for the evaluation of renal function. The samples were passing paraffin blocks and were staining with hematoxylin and eosin. The data were expressed as mean±SE and T-test was used. In the observations of kidney tissues of the newborns treated with gentamicin, there were several tissue injuries in comparison with the normal group such as lytic necrosis with picnotic nucleus occurred in the epithelium cells of kidney tubules. Moreover, in some epithelium cells of tubules, degeneration changes of the kind of hydropic and cytoplasmic vacuolation were observed. In the current study, though gentamicin had no significant effect on anomalies in newborns. it indicated however, that the intervention breastfeeding could have pathological effects and consequently, cause changes in the function factors of the kidneys of newborns.

KEY WORDS: Breastfeeding; Gentamicin; Newborn Mice.