OBJECTIVEto investigate pathological changes and mRNA expression of apoptosis genes bcl-2, bax and Caspase-3 in rat kidney tissue after rats are administrated with melamine for 28 days.

METHODS10 male SD rats and 10 female SD rats in each group were administrated with three doses of melamine (low dose, middle dose, high dose) by gavage for 28 days. The animals were divided into three experimental groups and one control group. The doses for male rats were 200, 400, 800 mg/kg, but for female rats they were 150, 300, 600 mg/kg. After melamine treatment the animals were sacrificed and the kidneys were taken out for pathological analysis and for detecting mRNA expression of bcl-2, bax and Caspase-3 with fluorescent quantitative PCR assay.

RESULTSthe tubular cylinders were observed in three experimental groups. The positive rates of tubular cylinders in three groups (from low dose to high dose) were 11/20, 13/20, 16/20, respectively. Additionally, melamine induced a significant decrease in mRNA expression of bcl-2 at low dose, middle dose or high dose, bcl-2 expression decreased by 20.58% - 49.51% in three groups treated with melamine. Furthermore, bax mRNA levels increased by 44.66% - 300.96% in groups treated with three doses of melamine, and Caspase-3 mRNA levels increased by 64.76% - 360.75% in groups treated with three doses of melamine.

CONCLUSIONSmelamine could induce pathological changes of rat kidneys, and it also induces a significant alteration of apoptosis Bcl-2, Bax and Caspase-3 mRNA expression in rat kidney tissue.