In utero and lactational 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure exacerbates urinary dysfunction in hormone-treated C57BL/6J mice through a non-malignant mechanism involving proteomic changes in the prostate that differ from those elicited by testosterone and estradiol.

A recent study directed new focus on the fetal and neonatal environment as a risk factor for urinary dysfunction in aging males. Male mice were exposed in utero and via lactation (IUL) to the persistent environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and then administered slow-release, subcutaneous implants of testosterone and estradiol (T+E2) as adults to mimic the hormonal environment of aging men. IUL TCDD exposure worsened T+E2-induced voiding dysfunction. Mice in the previous study were genetically prone to prostatic neoplasia and it was therefore unclear whether TCDD exacerbates voiding dysfunction through a malignant or non-malignant mechanism. We demonstrate here that IUL TCDD exposure acts via a non-malignant mechanism to exacerbate T+E2-mediated male mouse voiding dysfunction characterized by a progressive increase in spontaneous void spotting. We deployed a proteomic approach to narrow the possible mechanisms. We specifically tested whether IUL TCDD exacerbates urinary dysfunction by acting through the same prostatic signaling pathways as T+E2. The prostatic protein signature of TCDD/T+E2-exposed mice differed from that of mice exposed to T+E2 alone, indicating that the mechanism of action of TCDD differs from that of T+E2. We identified 3641 prostatic proteins in total and determined that IUL TCDD exposure significantly changed the abundance of 102 proteins linked to diverse molecular and physiological processes. We shed new light on the mechanism of IUL TCDD-mediated voiding dysfunction by demonstrating that the mechanism is independent of tumorigenesis and involves molecular pathways distinct from those affected by T+E2. AJCEU