Gene expression of angiotensin Ⅱ receptors in isolated glomeruli, tubules and arteries of aged rats / 中国病理生理杂志

ABSTRACT

AIM: To investigate the effects of aging on the angiotensinⅡ receptors (ATR) in different parts of the kidney. METHODS: Expression of AT 1 receptor in renal cortex was determined by Western and Northern blotting. Five micrometer thick cryostat sections of 3 or 24-month Wistar rats were mounted onto a 1.35?m thin polyethylene membrane. Glomeruli, tubules and arteries of rat kidney were isolated by laser microdissection and pressure catapulting system, AT 1aR mRNA, AT 1bR mRNA AT 2R mRNA were measured with reverse-transcription PCR(RT-PCR). RESULTS: Western and Northern blotting showed that protein and gene expression of AT 1 receptor in kidney cortex decreased in 24 month Wistar rats compared to those in 3 month Wistar rats. Glomeruli, tubules and arteries were quickly isolated by laser microdissection and pressure catapulting system without contamination. Compared to young group, AT 1aR mRNA expression was decreased in the tubules of aged rats, no changes was found in isolated glomeruli. AT 1bR mRNA was decreased in glomeruli and tubules. Both AT 1aR mRNA, AT 1bR mRNA were increased in the arteries. AT 2R mRNA was only increased in the tubules, whereas there were no significant changes in the glomeruli or arteries. CONCLUSION: Angiotensin Ⅱ receptors are regulated selectively in different portions of aged kidney, which might play an important role in aging related changes of the kidney.