Objectives: This study aimed to measure the effects of peroxisome proliferator-activated receptor-δ (PPARδ) agonist GW501516 (GW) and zinc sulfate (ZS) on ovariectomized rats’ vaginal histomorphology and collagen expression.
Methods: Two weeks after ovariectomy, rats received daily treatment with vaginal suppositories containing placebo, ZS, GW, ZS with GW, or estradiol for 2 weeks. Macroscopic measurements were taken and the midsection of the vagina was used for histology. Immunofluorescence was performed with antibodies against collagen I, III, and anti-actin or collagen I and V and anti-actin. Gene expression analysis of 3 collagen genes was performed by qRT-PCR.
Results: Macroscopic measurements revealed that the genital hiatus was narrower in the ZS and ZS with GW groups, and the vagina was significantly longer in the animals treated with GW, ZS with GW, and estradiol compared to the placebo group. Microscopic measurements of the vaginal layers showed that the lamina propria and the vaginal muscularis were significantly thicker in the ZS and ZS with GW group compared to the placebo.
The ratio of vaginal Col1a1/Col3a1 mRNA expression was significantly up-regulated by ZS with GW compared to placebo, whereas the ratio of vaginal Col1a1/Col5a1 expression was significantly up-regulated by ZS, GW, and ZS with GW. The ratio of vaginal collagen I/III protein expression was significantly up-regulated by ZS and ZS with GW, whereas the ratio of vaginal collagen I/V expression was significantly up-regulated by estradiol, ZS, and ZS with GW compared to control.
Conclusions: Vaginal suppositories containing zinc and PPARδ agonist significantly altered the vagina of ovariectomized rats.