# Investigation into Bioactive Selenium Species and the Mechanism of Action Behind Selenium-Enriched Rapeseed Flowering Stalks Alleviating Cadmium-Induced Toxicity in Mouse Sertoli Cells

## TL;DR

This study explores how selenium-enriched rapeseed flowering stalks protect mouse Sertoli cells from cadmium toxicity.

## Contribution

The study identifies specific bioactive selenium compounds and their mechanisms in mitigating cadmium-induced cytotoxicity.

## Key findings

- Water extract from selenium-enriched rapeseed flowering stalks showed the highest protective effect against cadmium toxicity.
- Methylselenocysteine and selenocystine were identified as key bioactive selenium species.
- The protective mechanisms involve reducing oxidative damage and inhibiting MAPK signaling pathways.

## Abstract

Cadmium (Cd) is a recognized environmental contaminant, present in soil, water, and food, which has been reported to cause male reproductive damage in vivo and vitro. Selenium-enriched rapeseed flowering stalks exhibit protective effects against Cd-induced reproductive damage, yet the bioactive components and underlying mechanisms remain unclear. We optimized the process of obtaining the crude extract (CE) via single-factor experiments. Subsequent bioassay-guided fractionation identified the water extract (WE) as significantly more effective in alleviating Cd-induced cytotoxicity compared to the petroleum ether extract, ethyl acetate extract, and n-butanol extract. High-performance liquid chromatography–inductively coupled plasma mass spectrometry (HPLC-ICP-MS) analysis revealed that WE contained the highest contents of methylselenocysteine (MeSeCys) and selenocystine (SeCys2) among four fractions. Both MeSeCys and SeCys2 exhibited protective effects against Cd-induced cytotoxicity. To further elucidate the underlying mechanisms, network pharmacology, RNA-Seq, qPCR, and Western blotting analysis were employed. The results revealed that WE exhibited good free radical scavenging capabilities, and the protective mechanisms of WE, MeSeCys, and SeCys2 against Cd-induced cytotoxicity were related to a reduction in oxidative damage, the inhibition of the ERK/p38 MAPK signaling pathway, and the suppression of cell cycle arrest, inflammation, and apoptosis triggered by Cd exposure. Collectively, these findings suggest that selenium-enriched rapeseed flowering stalks may serve as a promising dietary supplement in the prevention of Cd-induced reproductive toxicity.