EXPOSURE TO MELAMINE FROM THE EARLY POSTNATAL PERIOD CAUSES NEPROTOXICITY: A HISTOPATHOLOGIC AND ULTRASTRUCTURAL STUDY

Abstract

Objective: Melamine (mel), which is illegally added to formula to providing false-positive protein content, has caused acute renal failure in infants due to crystal formation. This study aimed to investigate the nephrotoxic effects of chronic low-dose mel exposure from the weaning period (supplementary food period). Materials and Methods: Eighteen female rats in the weaning period (21-days-old) were divided into three groups. A 0.1 ml saline was given to the control group by oral gavage (p.o). Fifty mg/kg mel was given to the second group and 75 mg/kg mel to the third group dissolved in 0.1 ml saline for twenty one days p.o.. At the end of the experiment, the animals were sacrificed, and histopathologic, morphometric, and ultrastructural analysis were performed on kidney tissues. Results: There was an inflammatory cell infiltration in the tubulointerstitial area, and no crystal formation was observed in either of the mel groups. In the 75 mg mel group, glomerular and tubular epithelial damage and significant increases in Bowman’s space were observed (p<0.05). In the ultrastructural analysis, the capillary lumen was closed due to endothelial enlargement, dilatation in the pedicles and hypertrophy in podocytes were found in the 75 mg group. Pedicles in the 50 mg group appeared to be enlarged more than the control group, but the capillary lumen was more open than the 75 mg group. Conclusion: The results show that low dose mel exposure causes kidney damage with increased doses from the early postnatal period.