Evaluation of the neuroprotective effects of ergosterol in a streptozotocin-induced Alzheimer's disease rat model: Insights into anti-inflammatory and antioxidant mechanisms.

Oxidative stress and neuroinflammatory processes constitute pivotal pathogenic mechanisms in the progression of Alzheimer's disease (AD), an age-associated neurodegenerative disorder, as well as in other neurodegenerative conditions. This study is the first to integrate in-silico TLR4-targeted molecular docking of ergosterol with comprehensive in-vivo validation, thereby providing mechanistic insight into its potential role as a neuroprotective agent. The present experimental work aimed to explore the effects of ergosterol (25, 50, and 100 mg/kg body weight) and its combination with the standard drug donepezil, as an antioxidant and anti-inflammatory agent, in a streptozotocin (STZ) induced AD rat model. In silico docking studies were first performed, in which ergosterol and donepezil were docked to the TLR4 receptor (PDB ID: 2Z62). The docking scores of ergosterol and donepezil were - 3.318 and - 3.934, respectively, with MMGBSA ΔG bind scores of -36.9 and - 39.19, ergosterol demonstrated neuroprotective potential with supportive computational evidence suggesting possible TLR4 interaction. RMSD values for both ergosterol-TLR4 and donepezil-TLR4 complexes indicated stable binding interactions. In the in-vivo STZ model, ergosterol administration significantly improved memory and learning impairments, as assessed by the Morris water maze, Novel Object Recognition Test, and Elevated Plus Maze Test. It also reversed changes in glutathione and malondialdehyde levels and showed protective effects in the hippocampus. Moreover, ergosterol ameliorated neuroinflammation by reducing glial cell activation. These findings provide experimental evidence that ergosterol prevents memory loss, learning impairments, oxidative stress, and neuroinflammation in ICV-STZ rats. In conclusion, ergosterol, either alone or in combination with donepezil, may constitute a promising therapeutic strategy against AD through its dual action on oxidative stress and neuroinflammation.