Lipopolysaccharide-induced apoptosis in a murine intestinal endocrine cell line by modulation of Bcl-2, Bax and caspase-3.

Numerous studies have focused on how to modulate the secretion of glucagon-like peptide 1 (GLP-1) due to its marked anti-diabetic function. However, few studies have investigated the apoptosis of enteroendocrine L cells, which secrete GLP-1. The aim of this study was to determine whether lipopolysaccharide (LPS), a gut bacterial product, is capable of inducing apoptosis in the intestinal endocrine cell line STC-1. We found that LPS is capable of reducing the viability of STC-1 cells in a concentration-dependent manner. annexin V/propidium iodide (PI) double staining detected by fluorescence microscopy and flow cytometry revealed a strong apoptosis-inducing ability for LPS in STC-1 cells. Furthermore, western blotting revealed that exposure to LPS significantly decreased the expression of Bcl-2 and increased the expression of Bax and caspase-3. In conclusion, LPS induced the apoptosis of STC-1 cells in a dose-dependent manner, which may be responsible for the reduced secretion of GLP-1 in diabetes.