Impact of caffeine on β cell proliferation and apoptosis under the influence of palmitic acid.

We examined the influence of caffeine on the proliferation and apoptosis of β cells cultured in vitro in the presence of the free fatty acid palmitic acid (PA). Different concentrations of caffeine (1-100 mM) and free fatty PA were added to cultured β cells. The MTT assay was used to analyze cell proliferative activity; flow cytometry was used to measure apoptosis and calculate the apoptosis rate. Compared with the blank control group, cells cultured with 500 mM PA for 24, 48, 72, and 96 h showed inhibition of pancreatic β cell proliferative activity. In the 10 and 25 mM caffeine groups cultured for 48, 72, and 96 h, β cell proliferative activity was much higher than that in the 500 mM PA group. The apoptosis rate in the 500 mM PA group was 40.55 ± 20.33%, which was higher than that in the blank control group. The apoptosis rates in the 10 and 25 mM caffeine group and the PA group were 19.12 ± 10.56 and 20.97 ± 9.75%, respectively, which was lower than that in the 500 mM PA group. At some concentrations, caffeine can improve free fatty PA levels and guide pancreatic β cell proliferation inhibition and cell apoptosis.