Vaginal birth is the leading risk factor for pelvic organ prolapse (POP), contributing to long-term pelvic floor dysfunction in up to 25% of women. Effective postpartum preventative strategies remain unavailable. This study explores the regenerative potential of an Aloe Vera–Alginate hydrogel (AV-ALG-Hyd), with and without SUSD2+ xenogeneic human endometrial mesenchymal stem cells (eMSC), in restoring pelvic floor integrity after simulated birth injury in a primiparous ovine model.

Simulated birth injury was induced using a Bakri© balloon catheter in primiparous ewes. Animals were randomised into four groups: (1) uninjured controls, (2) injury only, (3) AV-ALG-Hyd alone, and (4) AV-ALG-Hyd + eMSC. Treatments were injected post-injury. Tissue was assessed at 30 and 90 days using modified POP-Q scores, histology (H&E, Masson’s trichrome, elastin), immunohistochemistry (α-SMA, CD45), and uniaxial biomechanical testing (Figure 1). Statistical analysis used ANOVA with Tukey correction (p<0.05).

Birth injury led to disorganisation of collagen, elastin, and smooth muscle. Hydrogel + eMSC therapy significantly restored smooth muscle content at 30 days (↑2.1-fold vs. untreated, p<0.01) and achieved full smooth muscle bundle restoration by 90 days (p=0.004). Elastin abnormalities seen in untreated injury (↑40%, p=0.01) were normalised with hydrogel + eMSC by 30 and 90 days (↓25–35%, p<0.01). CD45+ cell density increased 3.8-fold in treated groups (p=0.0003), suggesting enhanced immune-mediated tissue remodelling. Biomechanically, maximum load and elastic modulus improved 2.3-fold and 180% respectively at 90 days (p<0.01), indicating functional recovery.

AV-ALG-Hyd, especially when combined with eMSC, promotes significant structural and functional repair following birth injury. This biologically active, injectable hydrogel offers a promising preventative therapy for POP, representing a paradigm shift in postpartum pelvic floor management.