Role of leukocyte adhesion molecules in monocyte/macrophage infiltration in weanling rats with unilateral ureteral obstruction

Abstract

Abstract Background Unilateral ureteral obstruction (UUO) of rats is a well‐established model for studying obstructive nephropathy. Meanwhile, pathophysiology of pediatric obstructive nephropathy is not well understood. In this report, we studied monocyte/macrophage infiltration and expression of intercellular adhesion molecule 1 (ICAM‐1) and macrophage antigen 1 (Mac‐1) in weanling rats with UUO. Methods Three‐week‐old male Sprague–Dawley rats underwent left unilateral ureteral ligation. Both obstructed kidneys (OBK) and contralateral kidneys (CLK) were harvested at 3, 6, 12, 24, 72 and 120 h after surgery. Monocyte/macrophage infiltration and expression of ICAM‐1 and Mac‐1 were evaluated immunohistochemically, and results were compared with those of sham‐operated control rats (SOK). Results Monocyte/macrophage infiltration was observed in the interstitium and perivascular region in the cortex of OBK within 6 h. The CLK and SOK showed slight monocyte/macrophage infiltration. Expression of ICAM‐1 was markedly observed in the periarterial and peritubular interstitium and in renal cortical peritubular capillaries 12 h after obstruction. In CLK and SOK, ICAM‐1 was slightly expressed in the endothelium of microvessels and parietal linings of Bowman's capsule. Expression of Mac‐1 was detected mainly in cells infiltrating the perivascular interstitium in OBK. In CLK and SOK, few Mac‐1‐positive cells were observed. Conclusions Adhesion molecules, ICAM‐1 and Mac‐1, are expected to recruit monocyte/macrophage infiltration into OBK of weanling rats with UUO.