TABLE 3.

Markers of male reproductive toxicity.

Marker	Expression	Reference
8-Hydroxy-2’-deoxyguanosine −8-OHdG	DNA damage due to DNA oxidation	Al-Hilli et al. (2018), Ommati and Heidari (2021)
Creatine	Excess creatine level in urine, indicating testicular damage	Zhang et al. (2014)
SP22 (sperm surface protein)	Relevance of toxins causes reduction in SP22 quality	El-Garawani et al. (2021)
Vitellogenins	Increased vitellogenin level shows toxic effects on male reproduction	Ge et al. (2016), Amthauer et al. (2021), Zhang et al. (2022)
Gene expression profiling (GEP)	Key marker of earlier risk of toxicity induction	Kier et al. (2004), Ommati and Heidari (2021)
D-aminolevulinic acid dehydratase (d-ALAD)	Biosynthetic enzyme and preliminary marker of lead poisoning that converts to porphobilinogen	Telišman et al. (2007)
Erythrocyte protoporphyrin (EP)	Exposure to heavy metals associated with age, alcohol, and smoking and lead serum biomarker	Telišman et al. (2007)
miR-27a	Inhibition of cysteine-rich secretory protein 2 (CRISP2) causes reproductive infertility	Zhou et al. (2017)
miR-34c-5p, miR-122, miR-146b 5p, miR-513a-5p, miR-374b, miR-509–5p, and miR181a	Reduced levels linked with azoospermia and asthenozoospermia and disruption of sperm regulation	Wang et al. (2011), Kong et al. (2012), Anyanwu and Orisakwe (2020)
piR-31704 and piR-39888	Key genotoxic factors and implied as an indicator of low sperm count	Cui et al. (2018), Anyanwu and Orisakwe (2020)