The effect of chromium on rat insulinoma cells in high glucose conditions

AimsIt has been suggested that Chromium (Cr), one of the essential minerals, can be beneficial to type 2 diabetic patients because it lowers blood glucose levels by improving various steps in insulin action. A few studies reported that Cr might also have some beneficial effects in people with type 1 diabetes mellitus and in streptozotocin-treated rats, but direct beneficial effects of Cr on pancreatic beta cells have not been proven. We performed this study to determine whether Cr could have direct protective effects on INS-1 cells in high glucose conditions that mimic the actual diabetic state.Main methodsINS-1 cells were cultured for 48 h in RPMI medium with 33 mM glucose as the stress condition and 11 mM glucose as a control. CrCl3 was used to verify whether Cr could protect INS-1 cells from glucotoxic stress. Cell viability and apoptosis were evaluated by MTT assay and FACS. The level of insulin mRNA, by semi-quantitative RT-PCR, was significantly reduced at 33 mM glucose concentration after 48 h of incubation.Key findingsCell viability was reduced by 50%, and 35% of the cells underwent apoptosis at the same culture condition. Addition of various concentrations of CrCl3 to INS-1 cells in 33 mM glucose for different durations of time did not reveal any beneficial effects on cell viability, degree of apoptosis, insulin mRNA levels, and glucose stimulated insulin secretion.SignificanceWe could not find any evidence that Cr had direct beneficial effects on INS-1 cells in high glucose induced stress conditions.