Effect of Probiotic Lactobacillus Casei on Secretory Immunoglobulin A (S-IgA) Levels in Rats Norvegicus Strain Wistar Post Ovariectomy

Estrogen promotes the growth of Lactobacillus colonies in the vagina, converting glycogen in superficial cells into lactic acid, resulting in a low vaginal pH that inhibits pathogenic bacteria. Post-menopause, Lactobacillus growth declines, leading to thinner secretions, higher vaginal pH, and a weakened immune system. This study investigates the effect of Lactobacillus casei extract on secretory immunoglobulin A (IgA) levels, vaginal acidity, and beneficial bacteria in the vaginal mucosa. An experimental post-test-only control group design was employed with 24 female rats aged 8-10 weeks, weighing 180-220 grams. Following ovariectomy and a 14-day acclimation, the rats were divided into four groups: a control group (K) with no treatment and three treatment groups (P1, P2, P3) receiving Lactobacillus casei extract at doses of 2ml, 2.25ml, and 2.5ml, respectively, administered orally for 14 days. On day 15, vaginal acidity was measured using a swab method, and IgA levels were assessed via ELISA; gram-positive staining was performed for bacterial identification. One-way ANOVA revealed that Lactobacillus casei extract significantly increased IgA levels and reduced vaginal acidity (p = 0.003 and p = 0.000). The reduction in acidity is attributed to Lactobacillus converting glycogen into lactic acid, maintaining vaginal acidity, while S-IgA on the mucosal surface acts as an opsonin and antigen-presenting cell to inhibit pathogenic growth. The study concludes that Lactobacillus casei extract can elevate secretory IgA levels and normalize vaginal pH.