Angiotensin II infusion induces nephrin expression changes and podocyte apoptosis.
OBJECTIVE
In in vitro studies, angiotensin (Ang) II has been demonstrated to promote podocyte apoptosis. The present study evaluates the effects of Ang II infusion in rats on podocyte nephrin expression and apoptosis and the molecular mechanisms involved in Ang II-induced proteinuria and mesangial expansion.


METHODS
Sprague-Dawley rats were randomly assigned to receive either normal saline or Ang II (400 ng x kg(-1) x min(-1)) by means of a mini-osmotic pump for variable time periods. Systolic blood pressure and urinary protein and albumin excretion rate measurements were carried out on days 7, 14, 21, and 28. The animals were sacrificed on days 14 and 28 and evaluated for serum creatinine, renal pathological changes, podocyte apoptosis, renal nephrin mRNA, and protein expression.


RESULTS
The Ang II-infused rats developed hypertension and proteinuria. On day 14, the Ang II-infused rats showed narrowing of the slit diaphragm, an increase in podocyte nephrin mRNA and protein expression, and alterations in its distribution along the foot processes. On day 28, the Ang II-infused rats demonstrated the presence of apoptotic podocytes and decreased nephrin mRNA and protein expression. There was a negative correlation between nephrin expression and the numbers of apoptotic podocytes (r = -0.63, p < 0.05).


CONCLUSIONS
These results suggest that changes in nephrin expression may play a role in the pathogenesis of Ang II-induced podocyte apoptosis.
Jia
Junya
J
Division of Nephrology, Renmin Hospital, Wuhan University, Wuhan, China.
Ding
Guohua
G
Zhu
Jili
J
Chen
Cheng
C
Liang
Wei
W
Franki
Nicholas
N
Singhal
Pravin C
PC
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001794:Blood Pressure / Q000187:drug effects; D003404:Creatinine / Q000097:blood; D006973:Hypertension / Q000139:chemically induced / Q000378:metabolism*; D020287:In Situ Nick-End Labeling; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D050199:Podocytes / Q000187:drug effects* / Q000648:ultrastructure; D011507:Proteinuria / Q000139:chemically induced; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D008565:Membrane Proteins; D012333:RNA, Messenger; C113267:nephrin; D000804:Angiotensin II; D003404:Creatinine