Protective Effects of Polydatin Amphiphilic Chitosan Nanocarriers Against an Aluminum Chloride-induced Model of Alzheimer's Disease in Rats: Relevance to Its Anti-inflammatory and Antioxidant Effects

Alzheimer's disease (AD) is the most frequent cause of dementia. Since there are complex pathophysiological mechanisms behind AD, and there is no effective treatment strategy, it is necessary to introduce novel multi-targeting agents with fewer side effects and higher efficacy. Polydatin (PD) is a naturally occurring resveratrol glucoside employing multiple mechanisms toward neuroprotection. In the current study, the anti-AD mechanisms of a novel amphiphilic chitosan nanocarrier formulation (ACN) of PD (NPD) were studied. After preparing the amphiphilic chitosan nanoformulation (i.e., NPD), physicochemical properties were assessed, including particle size, zeta potential, drug loading, drug release, MTT, Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). For in vivo analysis, aluminum chloride (AlCl3) was injected intraperitoneally for 14 days to induce AD in male Albino Wistar rats. To examine the anti-AD mechanisms of NPD, a total of 36 rats were divided into six groups of six. Behavioral tests, including open field, Y-maze, elevated plus maze, and shuttle box were done on days 7, 8, 14, and 15. Additionally, zymography, biochemical analysis, and histological studies were done. NPD, as a newly synthesized formulation for PD, potentially improved memory and cognitive behavioral parameters and reduced the activity of inflammatory matrix metalloproteinase 9 (MMP9) and serum nitrite levels, while increasing anti-inflammatory MMP2, antioxidant catalase, and glutathione. NPD also prevented morphological changes and increased neuronal survival in the CA2, CA4, and DG regions of the rat hippocampus. In conclusion, NPD is a novel formulation against AD through anti-inflammatory, antioxidant, and neuroprotective mechanisms.