Curcumin-loaded PLA-PEG copolymer nanoparticles for treatment of liver inflammation in streptozotocin-induced diabetic rats

This report focused on loading curcumin (CUR) drug into biodegradable Polylactide-poly(ethylene glycol) (PLA-PEG) copolymer nanoparticles as an effective anti-inflammatory agent in vivo to overcome the limitations resulted from the free CUR. By a simple nano-emulsification technique, hydrophobic CUR was loaded into hydrophobic polymer's segments and stabilized by cationic surfactant. They were then characterized by DLS, TEM, and SEM techniques providing monodispersed and spherical nanoparticles with an average diameter of 117 nm and high surface charge of + 35 mV. Thereafter, they were orally administrated into five groups of rats, typically, control (healthy rats), streptozotocin (STZ)-induced diabetic rats, diabetics treated with free CUR, diabetics treated with PLA-PEG NPs, and diabetics treated with CUR-encapsulated PLA-PEG NPs. Next, complete blood analyses were assessed including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and nuclear factor kappa B (NF-kappa B), reduced glutathione (GSH), malondialdehyde (MDA), nitric oxide (NO), cyclooxygenase (COX-2), Peroxisome proliferator-activated receptors (PPAR-gamma) and transforming growth factor-beta 1 (TGF-beta 1). The obtained results demonstrated that diabetes initially produced liver inflammation in rats manifested by leveraging the mean levels of serum AST, ALT inducing oxidative stress resulting in a clear increase in the levels of hepatic MDA and NO concomitant with a remarkable decrease in GSH. Moreover, diabetes significantly increased serum NF-kappa B, hepatic COX-2 and TGF-beta 1, while highly reduced hepatic PPAR-gamma. In contrast, both CUR free and CUR-encapsulated NPs ameliorated the negative changes in diabetes but CUR-encapsulated NPs showed more pronounced treated effect than free CUR. In addition, histopathological investigations were performed on the liver tissues of all groups, showing a mitigation in inflammation while treating with CUR-NPs.