Abstract:

Abstract:Objective
To investigate the influence of  tissue-specific growth hormone receptor(GHR) deficiency   in  type 1 diabetes in the mice at  the gene level using pancreatic β cells   combined with streptozotocin (STZ)-induced type 1 diabetes model.Methods The experiment was  divided into four groups:knockout mice group(LLc knockout group),using the homozygotes(LLc:LL+Cre)producted by  pancreatic β cell- specific expressed  recombinant enzyme  mice(RIP-Cre) and Cre-LoxP system modified GHR  mice (Floxed,LL);LL control group,containing Floxed GHR allele homozygous mice(LL);LLc STZ group and LL STZ group(STZ was used for inducing type 1 diabetes model mice).The mice with feeding glucose≥25 mmol•L^-1 were considered to be successful models.The Glucose Tolerance Test (GTT), pancreas tissue HE staining and immunohistochemistry were performed in the mice.Results The blood glucose of the mice in LL STZ group and LLc STZ group and LLc STZ group were increased after injection of STZ and the models achieved the diagnostic criteria for diabetes 16 d later.The results of GTT showed that compared with LLc control group and LLc knockout group,the blood glucose levels of the mice in LL STZ and LLc STZ groups were increased (P<0.05).There was no significant change of morphology and structure  of islets between LL control group and LLc knockout group detected by HE staining.The immunohistochemistry results showed that the  insulin level of the mice  in LL STZ group was significantly reduced compared with LL control group;the insulin level of the mice in LLc STZ group was reduced compared  with  LLc control group.Conclusion  Pancreatic β cell GHR gene knockout has no  effect on the  blood glucose and the function of β cells in the mice with STZ-induced type 1 diabetes.

Key words: growth hormone;growth hormone receptor;diabetes, type 1;insulin-secreting cells;gene , knockout;disease model,animal