Change of melanocortin receptor expression in rat kidney ischemia-reperfusion injury.

OBJECTIVES

alpha-Melanocyte stimulating hormone (alpha-MSH) may ameliorate renal ischemia-reperfusion (I/R) injury. Recent data suggest that melanocortin receptors may be related to the anti-inflammatory and immunomodulating action for alpha-MSH. We designed this experiment to determine the renal distribution of alpha-MSH receptors; melanocortin-1 receptor (MC-1R) and melanocortin-3 receptor (MC-3R).

METHODS

Sprague-Dawley male rats (n = 24) were randomly divided into 2 groups: the sham (n = 2) and the operation groups with warm ischemia (n = 12). Animals in the operation group were subjected to 40 minutes of warm renal ischemia. Western blotting analyses and immunohistochemistry were employed to determine expression of MC-1R and MC-3R.

RESULTS

Expression of MC-1R and MC-3R was decreased on 1 day after reperfusion. Immunohistochemical study confirmed the findings of Western blot analysis.

CONCLUSIONS

The present study demonstrated novel renal expression of MC-1R and MC-3R, especially in the outer medulla, representative of the renal I/R injury. Our current study suggested that the mechanisms of action of alpha-MSH may significantly attenuate the renal I/R injury by specific kidney-targeted effects via MC-Receptors as well as by systemic cytokine effects.