Abstract
Hepatocyte growth factor (HGF) has been studied as a protective factor for the survival of islet β cells and regulatory glucose transport and metabolism in many studies. The addition of exogenous HGF to cells or mice is the most common way to study HGF, but the persistence and stability of the administered HGF are unclear. In this experiment, wild-type C57BL6 (WT) mice and HGF-overexpressing transgenic (HGF-Tg) mice were divided into a normal diet (ND) group and an HFD group. The HGF protein level in the liver, kidney, spleen, pancreas, and VAT of HGF-Tg-ND mice was upregulated compared to that of WT-ND mice, and it was also upregulated in HGF-Tg-HFD mice compared to that in WT-HFD mice. In the ND group, though the HGF-Tg-ND mice showed higher fasted blood glucose levels and larger integrated density (IOD) of glucagon-positive cells than WT-ND mice, we found that HGF-Tg-ND mice can still maintain normal glucose tolerance based on an intraperitoneal glucose tolerance test (IPGTT) and an intraperitoneal insulin tolerance test (IPITT). In the HFD group, the HGF-Tg-HFD mice showed insulin sensitivity in IPGTT and IPITT and had larger areas and higher IOD values of islet β cells and smaller areas and IOD values of islet α cells than the WT-HFD mice. HGF-Tg-HFD mice had lower level of serum insulin than WT-HFD mice. The HGF-Tg-HFD mice showed inhibited accumulation of CD4+ T cells, CD8+ T cells, Ly6G+ neutrophils, and F4/80+ macrophages in the blood and tissues and protected liver and kidney functions. Oil Red O-stained liver sections revealed that WT-HFD mice had larger areas and higher IOD values of Oil Red O-positive cells than HGF-Tg-HFD mice, and WT-HFD mice had higher score of NASH. PAS-stained kidney sections found WT-HFD has higher mesangial area/glomerular area × 100% than HGF-Tg-HFD mice. Comparative analyses demonstrated that HGF reduces the proportions of inflammatory cells in the blood and tissues, and protects liver and kidney tissues by regulating glucose homeostasis of type 2 diabetic mice.