Background
Anal sphincter injury leads to fecal incontinence. Based on the regenerative capability of laser and human adipose-derived stem cells (hADSCs), this study was designed to assess the effects of co-application of these therapies on anal sphincter recovery after injury. Design: Male rabbits were assigned to equal groups (n = 7) including control, sphincterotomy, sphincterotomy treated with laser (660 nm, 90 s, immediately after sphincterotomy, daily, 14 days), hADSCs (2 × 106 hADSCs injected into injured area of the sphincter immediately after sphincterotomy), and laser + hADSCs. Ninety days after sphincterotomy, manometry and electromyography were performed, sphincter collagen content was evaluated, and Ki67, myosin heavy chain (MHC), skeletal muscle alpha-actin (ACTA1), vascular endothelial growth factor A (VEGFA), and vimentin mRNA gene expression were assessed.
Conclusion
The combination of laser and hADSCs appears more effective than either treatment alone for promoting myogenesis, angiogenesis, and functional recovery after anal sphincterotomy.
Results
The laser + hADSCs group had a higher resting pressure compared with the sphincterotomy (p < 0.0001), laser (p < 0.0001), and hADSCs (p = 0.04) groups. Maximum squeeze pressure was improved in all treated animals compared with the sphincterotomized animals (p < 0.0001), without a significant difference between treatments (p > 0.05). In the laser + hADSCs group, motor unit numbers were higher than those in the laser group (p < 0.0001) but did not differ from the hADSCs group (p = 0.075). Sphincterotomy increased collagen content, but the muscle content (p = 0.36) and collagen content (p = 0.37) were not significantly different between the laser + hADSCs and control groups. Laser + hADSCs increased ACTA1 (p = 0.001) and MHC (p < 0.0001) gene expression compared with laser or hADSCs alone and was associated with increased VEGFA (p = 0.009) and Ki67 mRNA expression (p = 0.01) and decreased vimentin mRNA expression (p < 0.0001) compared with laser.