Saponins from Panax japonicus improve neuronal mitochondrial injury of aging rats

Abstract

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 30 mg/kg) for 4 months. An in vitro model was established by d-galactose (d-Gal) in the SH-SY5Y cell line and pretreated with SPJ (25 and 50 µg/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 up-regulated 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.

Keywords:

• SPJ
• mitochondrial fission fusion
• mitochondrial function

Author contributions

Ting Wang and Zhi-Yong Zhou designed the study; Cheng Fan and Jin-Xin Wang conducted the experiments; Jin-Xin Wang and Zhang-E Xiong wrote the manuscript; Shan-Shan Hu, Ao-Jia Zhou, Ding Yuan, and Chang-Cheng Zhang carried out other experiments and analyzed the data. All the authors have read and approved the final manuscript prior to submission.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by the National Natural Science Foundation of China [NSFC81374001, NSFC81673778] and the Research Foundation of Wuhan Municipal Health Commission [WX21D02].