Exposure to Aroclor 1254 differentially affects the survival of pancreatic β-cells and α-cells in the male mice and the potential reason

Previous works showed that chronic exposure to Aroclor 1254 disrupted glucose homeostasis and induced insulin resistance in male mice. To further observe the different effects of Aroclor 1254 exposure on the pancreatic alpha-cells and beta-cells, male mice were exposed to Aroclor 1254 (0, 0.5, 5, 50, 500 mu g/kg) for 60 days, the pancreas was performed a histological examination. The results showed that the percentage of apoptosis cell (indicated by TUNEL assay) was increased in both alpha-cells and beta-cells, as the Aroclor 1254 dose was increased; the proliferation (indicated by PCNA expression) rate of beta-cells was elevated while that of alpha-cells was not affected, resulting in an increased beta-cell mass and a decreased alpha-cell mass in a dose-depend manner. The number of Pdx-1 positive beta-cells was significantly increased whereas that of Arx positive alpha-cells was markedly decreased, indicating an enhanced beta-cell neogenesis and a weakened alpha-cell neogenesis. The drastically reduction of serum testosterone levels in all the treatments suggested an anti-androgenic potency of Aroclor 1254. The up-regulation of estrogen receptors (ER alpha and ER beta) and androgen receptor in beta-cells might be responsible for the increased beta-cell mass and neogenesis.