Effects of Antibiotic-Disruption of the Seminal Fluid Microbiome on Male Reproductive Health and DOHaD Changes in Resulting Offspring

摘要

Paternal environment, including diet and obesity status, can lead to detrimental developmental origins of health and disease (DOHaD) effects in resulting offspring and even future descendants. Causative factors could include: 1) Alterations in the spermatozoa as they transition from the testes to the epididy-mis. For instance, sperm DNA fragmentation, total sperm count, and epigenetic alterations, including sperm microRNAs and tRNAs secreted from the epididymal tubules. 2) Paternal-induced DOHaD effects that lead to modifications in the seminal vesicle fluid contents, such as metabolites and cyto-kines. 3) Finally, a female may perceive the compromised state of her partner and reduce her parental investment in his offspring, as has been shown to occur in mammalian and non-mammalian species. One plausible mechanism that has not been previously considered is whether such paternal-induced DOHaD effects originate from alterations in a putative seminal fluid microbiome (SFM). The seminal vesicle glands secrete a slightly basic product enriched with fructose and other carbohydrates. This environment is an ideal habitat for microorganisms. Thus, we postulated the existence of a SFM that may be influenced by the male's environmental conditions. Prior studies in men have identified several bacterial species in the semen, which were presumed to originate from the seminal vesicles. However, bacteria identified from such samples could also originate from other portions of the male reproductive system or be urinary system contaminants. We have recently confirmed the existence of a SFM and that it can be influenced by genetic status and short-term consumption of a high fat diet in mice. Further, we used a combined antibiotic approach (CUB antibiotic protocol- Clindamycin 1.4 mg, Unasyn (ampicillin/sulbactam) 40 mg/kg day, and Baytril 50 mg/kg day) designed to target the primary bacteria within the SFM to demonstrate that alteration of the SFM in mice results in metabolic changes in the seminal fluid compared to males treated with saline vehicle alone (n = 10 per group). Inosine, xanthine, and L-glutamic acid were significantly reduced in the seminal fluid of antibiotic treated males; whereas fructose was increased in this treated group (P < 0.05). Pathological changes in the male reproductive system were observed, including increased Periodic acid-Schiff (PAS) + cells in the interstitium (potentially mast cells) of the testes and epididymis and cribi-form growth of epididymal tubules from CUB- antibiotic-treated males. Antibiotic-treatment also altered the bacterial composition of the SFM. Offspring derived from antibiotic-treated males paired with control females show developmental origins of adult health and disease (DOHaD) changes in postnatal ultrasonic vocalizations and increased body weight gain in later life (n=10 per group; P<0.05). The current studies are highly pioneering and suggest disruption of the SFM leads to DOHaD effects in resulting offspring and might compromise the health of the father. Further work is needed to determine how alterations in paternal composition, environment, and treatment with antibiotics might interact to affect the SFM and possibly result in more pronounced offspring DOHaD effects.