Mechanisms of renal tissue destruction in an experimental acute pyelonephritis

Abstract

To find out the mechanism of renal tissue destruction in Escherichia coli-induced acute pyelonephritis, the relationship between the infiltration of polymorphonuclear leukocytes into the kidney and the renal tissue damage has been investigated. An acute pyelonephritis was produced by administration of E. coli into the kidneysof the leukocyte-depleted and the leukocyte-nondepleted rats, and the sequence of morphologic events in the kidneys has been studied by light and electron microscopy. There was little infiltration of leukocytes into the E. coli-infected kidneys of the leukocyte-depleted rats despite formation of prominent bacterial colonies. Associated with this suppressed leukocytic infiltration into the kidney was a good structural preservation of those kidneys of leukocyte-depleted rats. On the contrary, a massive infiltration of polymorphonuclear luekocytes into the E. coli-infected kidneys was present in the leukocyte-nondepleted rats. Associated with this massive infiltration of leukocytes was a destruction of tubular basement membrane and tubular epithelia. The data appear to indicate that the polymorphonuclear leukocytes infiltrated into the kidney plays a role in renal tissue destruction in the early phase of E. coli-induced acute pyelonephritis.