Renal ACE and ACE2 expression in early diabetic rats.

Background/aim: The role of angiotensin-converting enzyme (ACE)-related carboxypeptidase-2 (ACE2) in the regulation of the renin-angiotensin system is not well characterized. This study investigated the changes in the expression of ACE and ACE2 in the kidney in early diabetic rats.

Methods: Streptozotocin-induced diabetic rats were examined. The concentrations of angiotensin II in plasma, urine, and renal cortex were measured by radioimmunoassay. The mRNA expression of ACE, ACE2, angiotensin II type 1 receptor (AT1R), and Mas receptor (MasR) in glomeruli and cortex was assessed using real-time PCR. The glomerular and cortical expression of ACE and ACE2 was assessed by immunohistochemistry.

Results: For renal cortical tissue, the angiotensin II level was more intensified in the 8-week diabetic rats. Immunohistochemical experiments showed that ACE was increased, but ACE2 was decreased in the glomeruli of 8-week diabetic rats, while both ACE and ACE2 in the tubules were increased. The AT1R mRNA in the glomeruli was decreased, while the MasR mRNA was increased in 2-week diabetic rats.

Conclusion: The combined effects of increased ACE and decreased ACE2 in glomeruli may be associated with the activation of the renin-angiotensin system in early diabetic rats, which is known to increase proteinuria.