[Effect of inducible nitric oxide synthase on pancreas islet apoptosis in rats].
OBJECTIVE
To investigate the effect and mechanism of cytokine and inducible nitric oxide synthase on apoptosis and function of rat pancreas islets cultured in vitro.


METHODS
Islets from Wistar rats were cultured in vitro and divided randomly into four groups: blank control group, cytokine group of islets cultured with TNF-alpha+IL-1beta, aminoguanidine (AG) group of islets cultured with aminoguanidine, and AG + cytokine group of islets cultured with TNF-alpha+IL-1beta and aminoguanidine. The nutrient fluid nitric oxide level and islets cNOS/iNOS activity were detected by test kit and the expressions of iNOS mRNA and apoptosis related gene (Bax, Bcl-2) were evaluated by RT-PCR. The viability of the islets was examined by AO/EB staining and the function of the islets was detected by insulin secretion index assay.


RESULTS
After co-cultured with cytokines IL-1beta and TNF-alpha, the expression and activity of iNOS in islet tissues enhanced (38.93+/-4.72) U/mL and the concentration of NO in medium increased remarkably(313.0+/-35.4) mol/L.The survival rate of cells and the insulin secretion index decreased with the up-regulation of proapoptosis gene and down-regulation of anti-apoptosis gene. But the activity of cNOS remained unchanged. Aminoguanidine reduced the cell apoptosis and increased the survival rate and insulin secretion index, and the activity of iNOS was inhibited.


CONCLUSIONS
iNOS plays an important role in the apoptosis of islets cultured by cytokines TNF-alpha and IL1-beta. Aminoguanidine prevents the islets from the damage of iNOS, alleviates the impairment of cytokines to islets, lessens the cell apoptosis and ameliorates the survival and function of islets.
Li
Bai-feng
BF
Department of General Surgery and Organ Transplantation, First Hospital, China Medical University, Shenyang 110001, China. syxialiping505@sohu.com
Liu
Yong-feng
YF
Cheng
Ying
Y
Zhang
Jia-lin
JL
D000818:Animals; D017209:Apoptosis; D002470:Cell Survival; D016207:Cytokines / Q000378:metabolism; D004789:Enzyme Activation; D015870:Gene Expression; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology* / Q000201:enzymology* / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D016207:Cytokines; D007328:Insulin; D019253:Proto-Oncogene Proteins c-bcl-2; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II