Silencing inducible nitric oxide synthase protects rat pancreatic islet.
OBJECTIVE
To investigate the effect of inducible nitric oxide synthase (iNOS) RNA interference on cytokine-induced injury of pancreatic islet in rats.


METHODS
Islets from Wistar rats were cultured in vitro and then randomly divided into five groups: group A, islets were cultured exclusively; group B, islets were transfected with negative control siRNA; group C, islets were transfected with iNOS siRNA; group D, islets were transfected with iNOS siRNA and then treated with TNF-alpha+IL-1beta; group E, islets were treated with TNF-alpha+IL-1beta. The expression of iNOS, Bax and Fas was determined by RT-PCR and Western blot. The viability of islet was examined by AO/EB staining and function was examined by glucose-stimulated insulin secretion (GSIS) assay.


RESULTS
The expression of iNOS and the promoting apoptosis gene Bax and Fas were significantly up-regulated by the induction of IL-1beta and TNF-alpha. Thus they led to apoptosis increase and the insulin secretion index decrease (1.87+/-0.31 vs 3.83+/-1.40, P<0.01). Silencing iNOS by RNAi prevented the up-regulation of Bax and Fas induced by cytokine, thus reduced apoptosis of islets and recovered the insulin secretion index (3.43+/-0.24 vs 1.87+/-0.31, P<0.01).


CONCLUSIONS
The apoptosis from cytokines to islets mediated by iNOS could be suppressed by RNA interference, which favors the survival and function of islets.
Bai-Feng
Li
L
Department of General Surgery, The First Hospital of China Medical University, North Nanjing Street No 155, Shenyang 110001, Liaoning Province, China. syxialiping505@sohu.com
Yong-Feng
Liu
L
Ying
Cheng
C
D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D015153:Blotting, Western; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D020287:In Situ Nick-End Labeling; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction
D052247:Nitric Oxide Synthase Type II