[Expression of mRNA for endothelin-1 and its receptors in rat kidney after burn injury].

Objective and methods: We studied expression of messenger RNAS for endothelin-1 (ET-1) and its receptor subunits (ETA, ETB) by northern blot hybridization and in situ hybridization in rat kidney following 30% TBSA full thickness burns.

Results: Expressions of that ET-1, ETA, and ETB mRNA expression are all evidently increased at 1 hour postburn. ET-1 and ETA reached its maximal mRNA expression at 3 hour postburn. ET-1 mRNA distributed primarily on glomerular endothelial cells and tubular epithelial cells in cortex. ETA mRNA predominantly presented on smooth muscle cells of small arterioles in renal cortex. However, the peak time of ETB mRNA expression is at 6 hour postburn and mainly localized on renal medullary tubular epithelial and collecting duct cells.

Conclusion: These findings suggest that 1. ET-1 acts principally as a local paracrine/autocrine peptide. 2. Increased ET-1 that activated ETA receptors accentuated expression on vascular smooth muscle cells will result in renal cortex ischemia. 3. Accentuated expression of ETB receptor on tubular epithelial cells may induce renal natriuretic action and reduction of water execretion. 4. Increased ET-1 and its receptors in kidney play an important role in the pathogenesis and development of renal function impairment following severe burn.