A Study on the Pathogenesis of Renal Papillary Necrosis Induced by Endotoxin

Sohn, Kyung Rak; Sohn, Tae Joong

Abstract

The author carried out an experimentation to clarify a possible pathogenesis of renal papillary necrosis induced by an univisceral Shwartzman reaction. The experimental animals were healthy white rabbits in weighing between 1.7 kg and 3.0 kg. Under the condition of ureterostomy, animals were pretreated with 0.5 cc of 50% ethyl alcohol and followed by administration of 0.2 ~ 1.5 mg endotoxin (E. coli 026 : B6, bacto lipopolysaccharide B. Difco, U.S.A.) as preparation in the renal pelvis. And then sacrificed at 10 minutes, 30 minutes, 1 hour, 2 hours, 6 hours and 24 hours after intravenous injection of 0.2 mg or 0.6 mg endotoxin through the ear veins, subjection to examine light and electron microscopically. The obtained results were summarized as follows: Papillary necrosis was developed in 88% among 18 cases excluding 6 cases died before sacrification. There were two types of necrosis, namely papillary and medullary type, but the former and combined forms of both types were the most common findings. Initial main target site of injury in renal papilla induced by endotoxiin was the endothelium of vasa recta and then followed by the Henle's loop, interstitial cell and collecting tubule respectively. Vascular injuries such as swelling and detachment of endothelium were observed since 10 minutes after endotoxin injection. Henle's loop showed stratification of basement membrane without consistent features with time lapses and initially observed fatty vaculoes at 1 hour after endotoxin injection were more eminent in 24 hours group. Main changes of interstitial cells were decrease of lipid droplets while increase of fatty vacuoles; the latter were initially observed in 1 hour group and more eminent in 24 hours group. Collecting tubule showed many fatty vacuoles especially in 24 hours group. It is thought that emergence of fatty vacuoles seems to be a kind of immature lipid droplets to compensate the increased demand of PC release due to continuous ischemic condition. In conclusion, it is thought that ischemic injury due to the vascular changes is pathogenic mechanism producing renal papillary necrosis. Endotoxin induced univisceral Shwartzman reaction in the kidney may be a good experimental model in studying renal papillary necrosis.