Investigating the protective effect of zinc oxide-gallic acid nanoparticles against depression like behavior and memory impairment in animals treated with D-galactose.

D-galactose-induced aging is an invincible phenomenon causing neurological disorders like depression, memory impairment etc., In the experiment, 30 male rats were allocated on an arbitrary basis into five groups (n = 6): (i) Water + Water; (ii) Water + D-galactose; (iii) D-galactose + Gallic acid; (iv) D-galactose + ZnO NPs, and (v) D-galactose + ZnO-gallic acid NPs. Each group received its respective treatment intraperitoneally, once daily for 28 days, according to body weight. After the treatment period, on the 29th and 30th days, behavioural tests Forced Swimming test and Morris Water Maze tests were performed for the assessment of depression and memory function, respectively. After that, decapitation was performed on the 31st day, and the rat brains were extracted and stored for biochemical, neurochemical, and histopathological analysis. Results showed that D-galactose-induced depression-like effects and impaired memory. D-galactose induced an increase in oxidative stress and inflammatory markers while decreasing antioxidant enzymes. The activity of AChE also increased by D-galactose administration. Histopathological assessment revealed deteriorative alterations in the brain. All of these behavioral, biochemical, neurochemical, and histopathological alterations caused by D-galactose were regulated by ZnO-gallic acidNPs. It is concluded that ZnO-gallic acidNPs, a nanocomposite, could be a better remedy for aging-related depression and cognitive impairment.