Protective effects of growth differentiation factor 11 on β-cell function in db/db diabetic mice and its possible mechanism / 中华内分泌代谢杂志

ABSTRACT

Objective To investigate the effects of growth differentiation factor 11 ( GDF11 ) on β-cell function in db/db mice and its possible mechanism. Methods Twenty eight-week-old male db/db mice were randomizedtoi.p. administration of GDF11(0.3mg·kg-1·day-1)or equivalent PBS(n=10)for 6 weeks.10age-matched male db/m were used as normal control, received equivalent PBS injection for 6 weeks. Blood glucose levels, body weights and food intake were monitored weekly. IPGTT and glucose-stimulated insulin secretion ( GSIS) were analyzed. After 6 weeks of intervention, serum HbA1C , TG, TC, and FFA were measured respectively. The concentrations of hormones in serum and pancreas were evaluated. The mRNA expression of Pdx-1, MafA, Nkx6. 1, and insulin2 were determined by RT-PCR. The expression of phosphorylated Smd2 (P-Smad2), Smad2 in islet were examined by western blot. Results Compared with NC group, GDF11 administration decreased FBG, HbA1C , modified lipid profiles. GDF11 improved glucose tolerance and augmented GSIS. Moreover, GDF11 increased serum insulin and pancreatic insulin content, while decreased serum glucagon concentration. The expression of Pdx-1, MafA, Nkx6. 1, and Insulin2 were significantly increased in GDF11 group. GDF11 elevated the expression of P-Smad2 in islets. Conclusion s GDF11 may preserve β-cell function and facilitate the secretion and production of insulin. Diminishing the metabolic abnormalities, alleviating the secretion of glucagon, as well as maintaining the key transcript factor activation may contribute to the amelioration of β-cell function after GDF11 administration. Smad2 pathway may be related to the protective effects of GDF11.