Saponins from Panax japonicus improve neuronal mitochondrial injury of aging rats

Context: Panax japonicus is the dried rhizome of Panax japonicus C.A. Mey. (Araliaceae). Saponins from Panax japonicus (SPJ) exhibit anti-oxidative and anti-aging effects. Objective: We evaluated the neuroprotective effects of SPJ on aging rats. Materials and methods: Sprague-Dawley rats (18-months-old) were randomly divided into aging and SPJ groups (n = 8). Five-month-old rats were taken as the adult control (n = 8). The rats were fed a normal chow diet or the SPJ-containing diet (10 or 30mg/kg) for 4months. An in vitro model was established by D-galactose (D-Gal) in the SH-SY5Y cell line and pretreated with SPJ (25 and 50 mg/mL). The neuroprotection of SPJ was evaluated via Nissl staining, flow cytometry, transmission electron microscopy and Western blotting in vivo and in vitro. Results: SPJ improved the neuronal degeneration and mitochondrial morphology that are associated with aging. Meanwhile, SPJ up-regulated the protein levels of mitofusin 2 (Mfn2) and optic atrophy 1 (Opa1) and down-regulated the protein level of dynamin-like protein 1 (Drp1) in the hippocampus of aging rats (p< 0.05 or p< 0.01 vs. 22 M). The in vitro studies also demonstrated that SPJ attenuated D-Gal-induced cell senescence concomitant with the improvement in mitochondrial function; SPJ, also upregulated the Mfn2 and Opa1 protein levels, whereas the Drp1 protein level (p< 0.05 or p< 0.01 vs. D-Gal group) was down-regulated. Discussion and conclusions: Further research on the elderly population will contribute to the development and utilization of SPJ for the treatment of neurodegenerative disorders.

Automated summary

This study evaluated the neuroprotective effects of Panax japonicus saponins (SPJ) on aging rats. The results showed that SPJ improved neuronal degeneration, mitochondrial morphology, and regulated the expression levels of Mfn2, Opa1, and Drp1 proteins. These findings suggest that SPJ may be a potential therapeutic agent for neurodegenerative disorders.