Curcumin-loaded nanoparticles effectively prevent T₄-induced oxidative stress in rat heart

In this study, we report the cardioprotective effect of the glycerol monooleate (GMO) based nanocurcumin in both in vitro and in vivo conditions under a hyperthyroid state. The heart is one of the primary target organs sensitive to the action of thyroid hormone, and slight variations in the thyroid hormone serum concentrations result in measurable changes in cardiac performance. Hyperthyroidism-induced hypermetabolism is associated with oxidative stress and is an important mechanism responsible for the progression of heart failure. Curcumin has been known to play a protective role against oxidative stress-related diseases like Alzheimer's, asthma, and aging due to its antioxidant properties. Nevertheless, its potent biological activity has been hindered due to its poor bioavailability. To overcome this drawback, a GMO-based biodegradable nanoparticle (NP) formulation loaded with curcumin has been developed, and the protective effect of curcumin-loaded NPs was compared against the native drug. Oxidative stress parameters like reactive oxygen species (ROS) release, change in mitochondrial membrane permeability, lipid peroxidation (LPx), lactate dehydrogenase (LDH) release, and the activity and protein expression of the endogenous antioxidant enzymes like superoxide dismutase, catalase (CAT) and glutathione peroxidase were evaluated. The results from in vitro showed that curcumin-loaded NPs showed better DPPH and NO radical scavenging activity than native curcumin in a concentrations range of 2.5-20 µM. It was also observed that the nanoparticulate curcumin was comparatively more effective than native curcumin in protecting against ROS-induced membrane damage by reducing LPx and LDH leakage at low concentrations of 5-10 µM. Further, curcumin NPs performed better in facilitating the activities of antioxidant enzymes under in vitro and in vivo conditions with respect to time and concentrations, resulting in reduced cellular ROS levels. In this scenario, we anticipate that curcumin-loaded NPs can serve as a better antioxidant than its native counterpart in protecting the heart from oxidative stress-related diseases.