Neuroimmunomodulation by allogeneic seminal vesicle fluid in CNS is sex-independent.

Objectives: Thymus-arisen FoxP3 regulatory T cells (Tregs) are one of the most important immunoregulatory mechanisms in the central nervous system (CNS) and pregnancy. Multiple sclerosis (MS) is an inflammatory disease of CNS associated with a reduced frequency and/or function of Tregs. Previous works have shown that seminal vesicle fluid affects female immune system and causes expansion of Tregs pool in the female reproductive tissue upon mating. Accordingly, it has been demonstrated that intra-CSF administration of seminal vesicle fluid from Wistar rats can ameliorate clinical sign of a female Lewis rat model of experimental autoimmune encephalomyelitis (EAE), the animal model of MS. The results indicated an up-regulation of FoxP3 expression in the brain and spinal cord. However, there are sex-based differences in the CNS structure & composition, sex hormones influence immune system, and gender-based differences affect treatment response. Therefore, we decided to find out if anti-inflammatory effect of seminal vesicle fluid is sex-dependent or -independent.

Methods: EAE was induced in male Lewis rats using guinea pig spinal cord and complete Freund's adjuvant. Intra-CSF injection was done on day 7 after EAE induction and the animals were followed-up until on day 14 after EAE induction when sacrificed. Then, brain and spinal cord of the animals were isolated, total RNA was extracted, and expression of mRNA for IFN-γ, IL-4, IL-17, and FoxP3 was determined using real-time PCR where β-actin was used as reference gene.

Result: demonstrated that intra-CSF administration of seminal vesicle fluid from male Wistar rats ameliorated EAE in male Lewis rats and increased FoxP3 in the brain and spinal cord.

Conclusion: This study suggests that seminal vesicle fluid from Wistar rats has anti-inflammatory effect on Lewis rats in a sex-independent manner. In addition, seminal vesicle fluid from Lewis rats had not beneficial effect on EAE in male Lewis rats. This is consistent with Tregs increase in allogeneic mating. More research is required to find out the immunologic aspect of allogeneic versus syngeneic administration of seminal vesicle fluid.