Experimental renal papillary necrosis in the Mongolian gerbil (Meriones unguiculatus)

Sequential light microscopic and ultrastructural examination of kidneys from male and light microscopic examination of female Mongolian gerbils given 250 mg 2-bromoethylamine hydrobromide (BEA)/kg body weight ip were performed. In addition, male Mongolian gerbils were treated with both BEA and ip injections of either water, dimethyl sulfoxide, piperonyl butoxide, or reserpine. Light microscopic renal lesions in male Mongolian gerbils progressed from congestion of the vasa recta of the proximal inner medulla at 6 hr post-treatment to total renal papillary necrosis (RPN) at 24 hr post-treatment. There was no sex difference in sensitivity to BEA. Ultrastructural alterations in male gerbils were restricted to the vasa recta. Vascular lesions of endothelial swelling and pericapillary edema in the vasa recta of the proximal inner medulla was observed 2 hr post-treatment and progressed to occlusion by platelets adherent to exposed basement membranes at 6 hr post-treatment. Diuresis induced by injections of saline and injections of dimethyl sulfoxide or piperonyl butoxide did not affect the development of BEA-induced RPN. Reserpine slowed the development of BEA-induced RPN by its vasodilatory effect on the renal vasculature, not by blocking the endothelial toxicity of BEA. RPN induced by BEA in the Mongolian gerbil is apparently an ischemic necrosis of the inner medulla that develops secondary to endothelial damage of the vasa recta.