Protective Potency of Baicalin Against Methylparaben-Induced Epididymal Sperm Impairments in Wistar Rats

Abstract

Methylparaben (MP) is a ubiquitous antimicrobial preservative linked to male reproductive impairment. This study evaluated the protective efficacy of baicalin, a bioactive flavonoid from Scutellaria baicalensis, against methylparaben-induced epididymal sperm toxicity in adult male Wistar rats. Forty-five rats were allocated into nine groups (n = 5): Normal Control; Vehicle Control; Methylparaben only (1000 mg/kg/bw); Baicalin controls (50, 100, 200 mg/kg/bw); and concurrent Protective groups receiving Methylparaben and Baicalin at 50, 100, or 200 mg/kg/bw. Treatments were administered via oral gavage daily for 28 days before assessing epididymal sperm count, motility, and morphology. Results showed that methylparaben alone significantly degraded all sperm indices, reducing count (151.33 x 106/ml), progressive motility (31.67%), and normal morphology (33.33%) compared to controls (p < 0.002). Co-administration of baicalin demonstrated a parameter-specific threshold effect. The lowest baicalin dose (50 mg/kg/bw) fully rescued normal sperm morphology (80.00%, p < 0.001) but failed to restore sperm count (162.67 x 106/ml), remaining statistically similar to the toxic methylparaben group. Conversely, medium and high doses (100 and 200 mg/kg/bw) completely protected all parameters, maintaining count, progressive motility, and structural integrity at baseline control levels (p > 0.05). In conclusion, methylparaben induces profound reproductive toxicity by disrupting sperm quantity, motility, and morphology. Co-treatment with baicalin exerts strong protective effects, though full rescue of epididymal spermatogenesis quality requires a therapeutic threshold of at least 100 mg/kg/bw.