Divine Aleru is an accomplished biochemist and researcher with a specialized background in environmental toxicology, focusing on the impacts of heavy metals on human health. With deep-rooted expertise in microbiome signatures analysis, Divine seamlessly blends rigorous scientific training with her passion for deciphering the intricate relationships between environmental exposures and the human microbiome. Her career is distinguished by a commitment to advancing integrative health interventions, leveraging cutting-edge microbiome research to illuminate how toxic metals shape biological systems. Driven by curiosity and innovation, Divine is dedicated to translating complex environmental findings into actionable insights that improve individual and public health outcomes. 
Divine Aleru is an accomplished biochemist and researcher with a specialized background in environmental toxicology, focusing on the impacts of heavy metals on human health. With deep-rooted expertise in microbiome signatures analysis, Divine seamlessly blends rigorous scientific training with her passion for deciphering the intricate relationships between environmental exposures and the human microbiome. Her career is distinguished by a commitment to advancing integrative health interventions, leveraging cutting-edge microbiome research to illuminate how toxic metals shape biological systems. Driven by curiosity and innovation, Divine is dedicated to translating complex environmental findings into actionable insights that improve individual and public health outcomes. What was issued?
This study explores the link between hexavalent chromium (Cr VI) exposure and semen quality impairment, with a focus on ribosomal DNA (rDNA) copy number variation as a potential underlying mechanism. The study used both human samples (from semen donors) and animal models (C57BL/6 J male mice) to examine the impact of Cr VI exposure on semen parameters such as sperm concentration, motility, and total sperm count. The research also investigated how changes in rDNA copy numbers, specifically the 5S and 45S rDNA, were associated with semen quality. The study found a negative correlation between blood and semen Cr concentrations and rDNA copy numbers, linking this variation to diminished semen quality. Furthermore, exposure to Cr VI induced rDNA copy number variation in testicular tissue and semen in mice, supporting the hypothesis that Cr VI contributes to reproductive toxicity via genetic instability.
Who is affected?
Individuals working in industries such as electroplating, leather tanning, and metallurgy, where Cr VI is used, are at high risk for exposure and subsequent reproductive health issues, particularly semen quality impairment. Populations living in areas near chromium-contaminated industrial sites may also face risks. The study’s findings are relevant to public health officials, reproductive health experts, and regulatory bodies tasked with monitoring environmental pollutants and workplace safety. Additionally, food manufacturers and companies involved in chromium-based production processes must be aware of these risks and implement effective safeguards to protect workers’ reproductive health.
Most important findings
The study revealed that Cr VI exposure, as evidenced by whole blood and semen chromium concentrations, was linked to poor semen quality in both humans and animals. Specifically, higher Cr VI levels were associated with decreased sperm concentration, motility, and total sperm count. Furthermore, Cr VI exposure was shown to cause variations in the rDNA copy number in both human semen and mice. The most significant finding was that a decrease in the rDNA copy number, particularly of the 5S and 45S rDNA, correlated with reduced semen quality. These results suggest that Cr VI exposure could impair semen quality through the induction of genetic instability, evidenced by rDNA copy number variation, which may serve as a potential biomarker for Cr VI-induced reproductive toxicity.
Key implications
This study’s findings underscore the need for stricter regulation and monitoring of Cr VI exposure in occupational settings, particularly in industries dealing with chromium compounds. The observed relationship between rDNA copy number variation and semen quality highlights a new potential mechanism for Cr VI-induced reproductive toxicity. Public health strategies should include guidelines to limit Cr VI exposure and regular screening for reproductive health in high-risk populations. Regulatory agencies could consider integrating rDNA copy number variation as a marker in health surveillance programs. For food manufacturers, especially those using chromium in their processes, implementing comprehensive safety protocols to protect workers from Cr VI exposure is crucial to maintaining workforce health and compliance with evolving environmental and occupational safety standards.
Citation
Huang, J., Jiang, Z., Ruan, Z., Sheng, H., Liu, S., Dong, X., Su, X., Feng, L., Li, Y., Xu, H., Chen, J., Xia, H., Li, T., Li, J., Xu, L., & Lou, J. (2024). Cr (VI)-induced ribosomal DNA copy number variation is associated with semen quality impairment: Evidence from human to animal study. Ecotoxicology and Environmental Safety, 282, 116700. https://doi.org/10.1016/j.ecoenv.2024.116700
