Effect of pancreatic stellate cell on apoptosis of beta-cell induced by high concentration of glucose

Objective To explore the influence of pancreatic stellate cells (PSCs) on the apoptosis of pancreatic islet cell line Ins-1 induced by high concentration of glucose. Methods A co-culture system was established, and Ins-1 apoptosis was evaluated by flow cytometry with Annexin IV/PI labeling after 24-hour treatment with and without 25 mmol/L glucose both in Ins-1 group and Ins-1+ PSCs group, respectively. Ins-1 vitality and nuclei morphological changes were observed with MTT and DAPI-staining respectively after 48-hour intervention with and without 25 mmol/L glucose. Results Both in the Ins-1 groups and the co-cultured groups, apoptosis rates of high glucose groups were higher than those of the controls (7.93%±0.41%, 3.73%±0.35%; 11.73%±1.20%, 5.03%±0.41%; F=55.68, P<0.05), and optical densities (ODs) of the high glucose groups were lower than those of the controls (2.28±0.13, 2.85±0.31; 0.62±0.06, 1.29±0.19; F=97.75, P<0.05). Apoptosis rates of the controls, high glucose group and hyperosmotic group in co-cultured groups were significantly higher than those of corresponding group in Ins-1 single groups (5.03%±0.41%, 3.73%±0.35%; 11.73%±1.20%, 7.93%±0.41%; 7.60%±0.72%, 5.60%±0.40%; F=55.68, P<0.05), and ODs were significantly lower (1.29±0.19, 2.85±0.31; 0.62±0.06, 2.28±0.13; 0.65±0.07, 2.35±0.12; F=97.75, P<0.05), and the typical nuclei morphological changes of apoptosis cells were observed. Conclusion Hyperglycemia contributes to the deterioration of beta-cell line Ins-1, and increases its apoptosis rate, possibly intensified in the context of PSC involvement. Key words: Diabetes mellitus; Pancreatic beta-cells; Pancreatic stellate cells; Apoptosis