(068) Perfluorooctane Sulfonate (pfos) And Perfluorooctanic Acid (pfoa) Sub-chronic Exposure has Minimal Impact on Erectile Function in Sprague-dawley Ratsa

Abstract

Abstract Introduction Per and polyfluoroalkyl substances (PFAS) are commonly used in industrial and consumer products and are environmental and health contaminants. The most common PFAS chemicals, perfluorooctane sulfonate (PFOS) and perfluorooctanic acid (PFOA), are used in firefighting foam, nonstick bakeware, water-resistant fabrics, grease-resistant paper and fire-resistant materials. PFAS is a known endocrine disruptor and can reduce testosterone and lower semen quality. The impact of PFAS exposure on erectile physiology is unknown. Objective Our study will assess the effect of PFOS and PFOA on erectile function in Sprague-Dawley rats. We hypothesize that PFOS and PFOA will decrease erectile function. Methods Adult male Sprague-Dawley rats were divided into three groups (n=10/group): 1) Control; 2) PFOS (10mg/kg/day); and 3) PFOA (10mg/kg/day). PFOS/PFOA was dissolved in 0.05% Tween 20 and administered in drinking water for 28 days. Controls received 0.05% Tween 20 in drinking water. The study was carried out in two different cohorts of rats (n=4 and n=6/group). Following 28 days of PFOS/PFOA exposure, rats were placed on regular drinking water for 2 weeks. Body weights were collected weekly and terminal organ weights of liver, testes, spleen, heart, lungs, brain, seminal vesicles, kidneys, bladder, and thymus were recorded. Erectile function was assessed prior to PFAS exposure and every 2 weeks thereafter via apomorphine-induced behavioral erections and yawns. Nerve-stimulated intracavernosal pressure and mean arterial pressure (ICP/MAP) was measured 2 weeks after exposure stopped. Results Four weeks of PFOS exposure significantly decreased body weight while PFOA exposure did not impact body weight (Con: 588±63.5g; PFOS: 453±16.3g; PFOA: 535±29.9g, p<0.01). The PFOS dose in the second cohort was overtly toxic with 5/6 rats dying following 3-4 weeks of exposure. Two weeks following PFOS/PFOA exposure, livers were markedly enlarged (Con: 19.4±2.85g; PFOS: 25.4±0.16g; PFOA: 20.2±3.77g, p<0.01), spleens were smaller (Con: 0.93±0.12g; PFOS: 0.65±0.03g; PFOA: 0.88±0.12g, p<0.05), and testes were larger in PFOS rats (Con: 1.8±0.07g; PFOS: 2.0±0.06g; PFOA: 1.8±0.07). No other organ weights were different across exposure groups. PFOS/PFOA exposed animals had similar numbers of apomorphine-induced erections throughout the 6 week period. Two weeks post-exposure, ICP/MAP was unchanged between all groups (n=5-10/group). Ongoing studies will assess testosterone levels. Conclusions A sub-chronic PFOS exposure markedly decreased body weight, increased liver size, decreased spleen weight, and increased testes weight. PFOA exposure did not impact body or organ weights. Following PFOS or PFOA exposure, there was no change in apomorphine-induced behavioral erections or ICP/MAP. Additionally, the dose of PFOS assessed was quite toxic to the second cohort of animals. Future studies will assess if a more chronic exposure will impact erectile function. Disclosure No.