Background
The transplantation of isolated pancreatic islets is a promising treatment for diabetes. Curcumin has been used for its pharmacologic effects, such as antidiabetic and anti-inflammatory activities. Tetrahydrocurcumin (THC), one of the major metabolites of curcumin, has been reported to have antioxidant and anti-inflammatory activities. This study examines the hypothesis that preoperative THC treatment can attenuate ischemic damage and apoptosis before islet transplantation.
Conclusions
These results suggest that preoperative THC administration enhances islet function before transplantation and attenuates the cytokine-induced damage associated with apoptosis.
Methods
Islets isolated from Balb/c mice were randomly divided into 2 groups and cultured in medium supplemented with or without THC. In vitro islet viability and function were assessed. After treatment with a cytokine cocktail consisting of tumor necrosis factor-α, interferon-β, and interleukin-1β, islet cell viability, function, and apoptotic status were determined. Proteins related to apoptosis were analyzed using INS-1 cell after streptozocin treatment.
Results
There was no difference in cell viability between the 2 groups. Islets cultured in the medium supplemented with THC showed 1.3-fold higher glucose-induced insulin secretion than the islets cultured in the medium without THC. After treatment with a cytokine cocktail, glucose-induced insulin release, and NO of the islets were significantly improved in THC-treated islets compared with islets not treated with THC. Apoptosis was significantly decreased, and B-cell lymphoma-2 was elevated in the THC-treated group. The streptozocin-treated INS-1 cell produced significantly higher levels of and B-cell lymphoma-2-associated X protein, caspase-3, and caspase-9 than INS-1 treated with THC. Conclusions: These results suggest that preoperative THC administration enhances islet function before transplantation and attenuates the cytokine-induced damage associated with apoptosis.