Glutamate is the major excitatory neurotransmitter in the central nervous system and plays a critical role in maintaining normal neuronal function. However, excessive extracellular accumulation of glutamate under pathological conditions induces excitotoxicity, which is closely associated with oxidative stress, mitochondrial dysfunction, and subsequent neuronal cell death. S-allyl cysteine (SAC) is a compound derived from aged garlic, known for its antioxidant and potential cardioprotective properties. The present study investigated the neuroprotective effects of SAC against glutamate-induced cytotoxicity in mouse hippocampal HT22 cells. HT22 cells were exposed to glutamate to establish an in vitro oxidative neurotoxicity model. SAC was administered 2 h prior to glutamate exposure to evaluate its protective potential. Cell viability was assessed using the MTT assay, and glutamate-induced morphological changes were examined by phase-contrast microscopy. Glutamate treatment significantly reduced cell viability in a dose-dependent manner and induced characteristic neuronal damage, including cell shrinkage, dendritic loss, and decreased cell density. SAC treatment alone did not affect cell viability, indicating that SAC is non-cytotoxic within the tested concentration range. Notably, pretreatment with SAC significantly attenuated glutamate-induced cytotoxicity and improved glutamate-induced morphological alterations, thereby preserving neuronal structure and reducing cellular damage. In conclusion, SAC exerts significant protective effects against glutamate-induced oxidative neurotoxicity in HT22 cells. These findings suggest that SAC may serve as a promising neuroprotective agent for excitotoxicity-related neurological disorders.

The aim of this study was to enhance the proliferation efficiency of spermatogonial stem cells (SSCs). In order to improve the proliferation efficiency, we investigated new factors that promote the proliferation of SSCs using in vitro culture method with natural plant extracts. Germ cell populations containing SSCs were collected 6- to 8-days-old from C57BL/6-TG-EGFP (C57GFP) mice and SSCs were isolated from the collected cells via magnetic-activated cell sorting (MACS). Since then, SSCs were cultured for a week with culture medium containing natural plant extracts at concentration of 0.1, 1, and 10 μg/mL. After a week of culture, we looked for an increase, especially a dose-dependent increase, in the number of cells compared to that of the control group. A dose-dependent increase, in the number of cells was observed in the Petasides japonicus-treated groups. Furthermore, we carried out repeated experiment that is process consisting of selection and additional segmentation to explore new factors for activating SSCs at the molecular level. As a results, Petasides japonicus butanol fraction significantly increased the proliferation rate of SSCs in a dose-dependent manner among Petasides japonicus fraction samples. We identified normal expression level of PLZF in SSCs cultured with plant extracts using immunocytochemistry method. Furthermore, we also carried out qRT-PCR and identified normal expression level of Lhx1 and GFRα1. The finding of this study could contribute to improvement of proliferation and activation for SSCs, using culture method with natural plant extracts.