Probiotic Modulation of the Gut–Ovary and Gut–Myometrium Axes: An In Vitro Study

Emerging evidence suggests that gut microbiota significantly influence female reproductive health by affecting hormonal, immune and metabolic processes. This research explored how a probiotic blend comprising <i>Lactobacillus crispatus</i> novaLCR6, <i>Limosilactobacillus fermentum</i> novaLF58 and <i>Bifidobacterium bifidum</i> novaBBF9 affects the gut-myometrium and gut-ovary axes. Intestinal epithelial cells were exposed to individual probiotics or their combination using a Transwell^® setup; their effects on barrier integrity, probiotic activity and short-chain fatty acid production were measured. Subsequently, basolateral metabolites were applied to myometrial and ovarian cells to assess viability, proliferation, oxidative stress, inflammation, signalling pathways and hormone production. All probiotics enhanced intestinal cell viability and barrier function. The combined probiotic showed synergistic effects, enhancing butyrate production by ~23-51%, improving myometrial proliferation by up to ~78%, decreasing ROS and TNF-α levels by ~49% and ~74% and modulating oxytocin signalling. In ovarian cells, the probiotic mixture activated ERK/MAPK and PI3K/AKT pathways, normalised PAK1, ERβ and PAX8 expressions and significantly increased LH and FSH secretion compared to single strains. These findings suggest that a multi-strain probiotic may modulate pathways involved in reproductive tissue homeostasis through gut-reproductive axis interactions, providing mechanistic insight from an <i>in vitro</i> study.