Figure 4.

Melatonin attenuates the smoking‐induced apoptosis. (A) In immunohistochemistry (IHC) images, the white arrow shows the expression of the apoptotic caspase‐3 in the islet. (B) The average integrated optical density (IOD) value for caspase‐3 in the IHC image. (C) Western blot analysis of cleaved caspase‐3 expression in β cells, which were cultured in the medium with 5% rat serum of different groups for 24 h. (D) Quantitative analysis of cleaved caspase‐3 expression. (E and F) TUNEL assay to detect apoptotic cells in islets. #P > .05 melatonin control vs normal control, *P < .05 smoking vs normal control, **P < .05 smoking+melatonin vs smoking