Protective role of sodium butyrate, a HDAC inhibitor on beta-cell proliferation, function and glucose homeostasis through modulation of p38/ERK MAPK and apoptotic pathways: Study in juvenile diabetic rat

Type 1 diabetes (T1D) also known as juvenile diabetes is a chronic autoimmune disorder that precipitates in genetically susceptible individuals by environmental factors particularly during early age. Both genetic and epigenetic factors are implicated in the beta-cell development, proliferation, differentiation and function. Recent evidences suggested that there is a link between diabetes and histone deacetylases (HDACs), because HDAC inhibitors promote beta-cell development, proliferation and function as well as improve glucose homeostasis. Sodium butyrate (NaB) is a short chain fatty acid having HDAC inhibition activity. The present study was aimed to investigate the protective role of NaB treatment on the beta-cell proliferation, function and glucose homeostasis as well as apoptosis in juvenile diabetic rat. Diabetes was induced by single injection of STZ (60 mg/kg, i.p.) in chilled citrate buffer, while NaB (500 mg/kg/day) was administrated by i.p. route for 21 days as pre- and post-treatment schedule. Plasma glucose and insulin levels, HbA1c, glucose tolerance, apoptosis, and expression of proliferating cell nuclear antigen (PCNA), p38, p53, caspase-3, extracellular signal-regulated kinase-1/2 (ERK-1/2), forkhead box protein O1 (FOXO1) and insulin receptor substrate-1 (IRS-1) as well as histone acetylation were evaluated. NaB treatment decreased plasma glucose, HbA1c, beta-cell apoptosis and improved plasma insulin level and glucose homeostasis through HDAC inhibition and histone acetylation in diabetic animal as compared to control. NaB treatment improved the beta-cell proliferation, function and glucose homeostasis as well as reduced beta-cell apoptosis in juvenile diabetic rat by the modulation of p38/ERK MAPK and apoptotic pathway.