Effect of Troglitazone (Tz) and N-Acetyl Cysteine (Nac) Treatment on Beta Cells' Survival, and Insulin Production Under Hyperglycaemic Conditions

Background Type I diabetes mellitus is characterized by the deficiency of insulin‐producing beta cells but there is still a substantial number of beta cells found in the pancreas and secrete insulin at the time of diagnosis. The mTOR pathway can directly influence insulin production by affecting multiple translation factors, one of which is decreasing eIF‐4E inhibition which, in the same time, can be activated by the indirect insulin production enhancer, ERK phosphorylation pathway. Aim The purpose of this study is to find out the combined effects of TZ and NAC on Beta‐cells insulin production and survival under hyperglycemic conditions (24 hours and 72 hours) and explore the effect of different TZ concentrations under 72h hyperglycemic conditions. Methods GRINCH cells were prepared, cultured, and divided into separate 24‐well plates (200,000 cell/well) and 96‐well plates (10,000 cell/well). The experiment was performed on a total of 8 wells, 4 for each type of well plates; 2 for 24hrs, and 2 for 72hrs treatments; 1 being normoglycemic and 1 being a hyperglycemic well for each time condition. Apart from the controls, each plate had 3 treatment groups. The first group was the cells treated with TZ (10μM). The second group was the cells treated with NAC (2mM). The third group was the combination of NAC with TZ along with the cells. All groups contained an adequate amount of media in relation to the treatment. To explore the effects of different TZ concentrations, two extra 24‐well plates with GRINCH cells were prepared, one for each environment (hyper and normoglycemic conditions). 3 different TZ concentrations were used, 10, 5, and 2.5μM along with their respective vehicle controls. measurements were taken at 24 and 72 hours. Results All the three groups showed increased insulin production in normoglycemic 24hrs condition, however, in 24hrs hyperglycemia, only NAC and the combination of NAC and TZ showed an increase while TZ stayed the same. In 72hrs normoglycemia, TZ and NAC showed a decrease while their combination showed no change. While in 72hrs hyperglycemia both TZ and the combination decreased but NAC increased. The only 2 conditions with increased survival were NAC and TZ individual treatment in 72hrs normoglycemic conditions. Concerning the second part of the experiment; 2.5μM showed an increase in insulin production. Conclusion There was no positive proof of the combination (TZ and NAC) effect in chronic 72hrs hyperglycemia which possibly excludes its use in diabetics, however, there positive effects in acute 24hrs hyperglycemia should be further investigated. Furthermore, the fact that at a certain concentration TZ was able to increase insulin proves that there is a point at which by using TZ, ERK and mTOR pathways both would be enhanced to increase insulin production which gives more incite of Thiazolidinediones effects in diabetic patients. Support or Funding Information This work was supported by the University of Sharjah and the Boehringer Ingelheim Pharmaceutical company. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .