Experimental Analysis of Vaginal Laxity in Rats Treated With a Combination of Er:YAG Fractional Lasers and AMSC-MP.

Introduction: Vaginal laxity, a symptom of pelvic floor dysfunction observed in women, has many negative biological and psychological impacts. Laser treatments and stem cell-based therapies are emerging therapeutic methods for treating this condition. This study aimed to determine changes in vaginal laxity in model rats using a combination therapy of erbium-doped yttrium aluminium garnet (Er:YAG) fractional lasers and topical treatment with amniotic membrane stem cell metabolite products (AMSC-MP). Methods: The experimental animal population comprised 36 female white rats (Rattus norvegicus; 2-day-post-vaginal-delivery rats) allocated into the following four groups (n=9): K1, untreated two-day-post-vaginal-delivery rats; K2, two-day-post-vaginal-delivery rats treated with topical gel without AMSC-MP; P1, two-day-post-vaginal-delivery rats treated with Er:YAG fractional lasers and topical gel without AMSC-MP; P2, two-day-post-vaginal-delivery rats treated with Er: YAG fractional lasers and topical gel containing AMSC-MP. Immunohistochemical (IHC) examination was carried out for the expression and activity of heat shock protein 70 (HSP-70), collagen-1, tissue inhibitors of metalloproteinase 1 (TIMP-1) and matrix metalloproteinase 1 (MMP-1), as well as vaginal mucosal thickness. Results: There was a significant difference (P<0.05) in the expression of HSP-70 among all groups except K2 and P1 (P>0.05); there was no significant difference in type I collagen and TIMP-1 expression between the groups (P>0.05); there was a significant difference (P<0.05) in MMP-1 activity, with the activity in the K2 group (5.79±0.83) being higher than that in the P1 group (4.44±1.82) and that in the K1 group (5.74±1.03) being higher than that in the P2 group (4.24±1.55). Also, there was a significant difference in the thickness of the vaginal mucosa in all groups except K2 and P1 (P>0.05). Conclusion: Er:YAG fractional laser and AMSC-MP combination therapy improved vaginal laxity in model rats by increasing Hsp70 expression and vaginal mucosal thickness and decreasing MMP-1 activity.