Characterization, Analysis, and Alleviating Effects of Sulfated Polysaccharides Derived From Agardhiella subulata on Di-(2-Ethylhexyl) Phthalate-Induced Testicular Toxicity in Mice.

Exposure to di-(2-ethylhexyl) phthalate (DEHP) adversely affects the reproductive system. Agardhiella subulata extracts are known for their antioxidant and hepatoprotective properties, yet their effects against DEHP-induced testicular toxicity remain unclear. This study investigated the extraction, characterization, and protective effects of A. subulata sulfated polysaccharide (ASP) against DEHP-induced testicular damage. Autoclave-assisted extraction yielded 40.4% ASP. Chemical and structural characterization using HPLC and NMR identified ASP as a sulfated carrageenan predominantly composed of β-Gal4S and DA2S, with minor impurities. In mice exposed to DEHP (200 mg/kg/day) for 10 weeks, ASP treatment (50 or 200 mg/kg/day via oral gavage) significantly improved testicular weight, sperm count, and motility, while alleviating seminiferous tubule atrophy and germinal epithelium degeneration. ASP attenuated oxidative stress by normalizing MDA, SOD, and GSH levels. Mechanistically, ASP activated the Nrf2/HO-1 antioxidant signaling pathway, suppressed caspase-3 and caspase-8 expression, reduced inflammation, and enhanced steroidogenesis by increasing stAR and 3β-HSD expression and serum testosterone levels. Overall, these findings demonstrate that ASP effectively mitigated DEHP-induced testicular toxicity through antioxidant, anti-apoptotic, anti-inflammatory, and steroidogenic mechanisms. These findings suggest that ASP is a promising natural agent for protecting against DEHP-induced reproductive toxicity and improving testicular function. Thereby supporting SDG goals 3, 12, and 15.