Effects of zinc supplementation on metallothionein levels in ischemic renal tissue.

We investigated how zinc (Zn) supplementation affects metallothionein levels in the cortex and medulla of ischemic renal tissue of rats. We used adult male rats divided into four groups: group 1, untreated control; group 2, sham-operated; group 3, ischemia-reperfusion; group 4, ischemia-reperfusion + 5 g/kg Zn. Renal tissue was analyzed using immunostaining of rat metallothionein. Cells stained with metallothionein were counted and their percentage was calculated. We found that the Zn supplemented ischemia and reperfusion group exhibited a greater percentage of cells stained strongly for metallothionein in the renal cortex than all other groups. In the renal medulla, percentages of weak staining for metallothionein in the control and ischemia and reperfusion groups were greater than those in the sham and Zn-supplemented ischemia/reperfusion groups. Our findings indicate that the main effect of Zn in the renal tissue occurs in the cortex, while metallothionein synthesis in the renal medulla is unaffected.