Arachidonic acid and lipoxin A4 attenuate alloxan‐induced cytotoxicity to RIN5F cells in vitro and type 1 diabetes mellitus in vivo

Abstract

We studied whether polyunsaturated fatty acids (PUFAs) can protect rat insulinoma (RIN5F) cells against alloxan-induced apoptosis in vitro and type 1 diabetes mellitus (type 1 DM) in vivo and if so, mechanism of this beneficial action. In vitro study was conducted using RIN5F cells while in vivo study was performed in Wistar rats. The effect of PUFAs, cyclo-oxygenase and lipoxygenase inhibitors, various eicosanoids and PUFAs metabolites: lipoxin A4 (LXA4), resolvin D2 and protectin against alloxan-induced cytotoxicity to RIN5F cells and type 1 DM was studied. Expression of PDX1, P65 NF-kB and IKB in RIN5F cells and Nrf2, GLUT2, COX2, iNOS protein levels in the pancreatic tissue and plasma glucose, insulin and tumor necrosis factor-α and antioxidants, lipid peroxides and nitric oxide were measured. Of all, arachidonic acid (AA) was found to be the most effective against alloxan-induced cytotoxicity to RIN5F cells and preventing type 1 DM. Both cyclo-oxygenase and lipoxygenase inhibitors did not block the beneficial actions of AA in vitro and in vivo. Alloxan inhibited LXA4 production by RIN5F cells and in alloxan-induced type 1 DM Wistar rats. AA-treatment restored LXA4 levels to normal both in vitro and in vivo. LXA4 protected RIN5F cells against alloxan-induced cytotoxicity and prevented type 1 DM and restored expression of Nrf2, Glut2, COX2, and iNOS genes and abnormal antioxidants to near normal. AA seems to bring about its beneficial actions against alloxan-induced cytotoxicity and type 1 DM by enhancing the production of LXA4. © 2016 BioFactors, 43(2):251-271, 2017.