Pathologies of the female reproductive system, characterized by chronic pain, are frequent and it has been hypothesized that inflammation may play an essential role in their pathogenesis. It is known that androgens, including dihydrotestosterone (DHT), have shown immunomodulatory effects in experimental models of chronic inflammation. The aim of this study was to evaluate the immunomodulatory effects of DHT in smooth muscle cells (rSMCs) isolated from vagina of intact Sprague-Dawley rats and investigate the tissue expression of steroidogenesis enzymes, in order to evaluate the hormone on-site role. rSMC isolated from rat distal vagina were characterized with α-smooth muscle actin (α-SMA) and myosin heavy chain 11 (MHCII). Then rSMC were left untreated (NT, taken as control) or pre-treated for 24 h with DHT (30 nM) with or without the anti-androgen bicalutamide (BICA; 1 μM) and then stimulated with LPS (100 ng/ml). Using Real-Time RT PCR we evaluated the mRNA expression of membrane Toll-Like Receptors (TLRs), mediators of inflammatory response, and the expression of the main pro-inflammatory markers (IL-6, IL-1β, chemokine C-X-C motif ligand 1 (CXCL1), COX-2 and MCP). In addition, the expression of the main genes involved in the steroidogenesis was evaluated in distal vaginal tissue. Finally, immunofluorescence studies were performed to analyse the nuclear translocation of NF-kB, an important transcriptional mediator of the inflammatory response. Our results showed that rSMCs expressed constitutively all TLR receptors, identifying rSMCs as potential non-professional Antigen Presenting Cells (APC). LPS stimulation increased mRNA expression of CXCL1, IL-1β, MCP1, IL-6 and COX2, whereas DHT counteracted this effect. In addition, DHT significantly decreased LPS-induced nuclear translocation of NF-kB, and all these effects were blunted by BICA co-treatment. Finally, distal vagina tissues expressed enzymes related to the production of androgenic precursors (CYP11A1) and DHEA (CYP17A1), albeit to a lower level when compared to the ovary, whereas genes related to the synthesis of testosterone (HSD17β3) and DHT (SRD5A2) were significantly more expressed. In conclusion, our data show that in rSMCs DHT plays an anti-inflammatory role, inhibiting the mRNA expression of pro-inflammatory genes as well as the NF-kB nuclear translocation induced by LPS. These effects are blunted by BICA, thus suggesting a direct involvement of the androgenic receptor in this pathway. Moreover, the high expression of genes involved in androgen synthesis in the distal vagina suggests the possible therapeutic use of androgen precursors (e.g. DHEA) for the treatment of genitourinary trait disorders in women.
18 May 2019 - 21 May 2019