Hydrogen-Rich Water Alleviates the Nickel-Induced Toxic Responses (Inflammatory Responses, Oxidative Stress, DNA Damage) and Ameliorates Cocoon Production in Earthworm.

Abstract

This study examined the capacity of hydrogen-rich water (HRW) to counteract nickel chloride toxicity in an earthworm model over a 14-day exposure period at concentrations of 10, 200, and 500 mg nickel per kg soil. Compared with groups receiving untreated water, earthworms exposed to nickel in HRW showed markedly lower reactive oxygen species (ROS) levels, reduced expression of the DNA oxidation marker 8-hydroxy-2'-deoxyguanosine (8-OHdG), and diminished TNF-α-mediated inflammatory signaling. Histopathological assessment revealed less epithelial degeneration, epithelial necrosis, and muscle fiber necrosis in HRW-treated animals. Cocoon production, which declined under high nickel exposure, was better preserved in the HRW groups. These findings indicate that HRW can mitigate heavy-metal-induced oxidative and inflammatory injury in soil organisms, suggesting potential utility as an environmentally benign approach to managing heavy-metal contamination.

Mechanism

HRW scavenges reactive oxygen species generated by nickel exposure, thereby suppressing ROS accumulation, TNF-α-driven inflammatory responses, and 8-OHdG DNA oxidative damage, which collectively reduces histopathological tissue injury in earthworms.