<![CDATA[Fecal incontinence may arise following anal sphincter injury, yet currently available treatments have limited capacity to restore sphincter integrity. The secretome derived from hypoxia-conditioned mesenchymal stem cells (MSCs) represents a potential cell-free regenerative therapy because of its putative immunomodulatory and tissue-remodeling properties. The aim of this study was to investigate the effects of hypoxia-conditioned human umbilical cord MSC secretome on inflammation, fibrosis, collagen deposition, and hypoxia-inducible factor-1 alpha gene (HIF-1A) expression following sphincterotomy. Male Sprague–Dawley rats were randomly assigned to receive either hypoxia-conditioned MSC secretome or 0.9% NaCl after surgical sphincterotomy. Histopathological evaluations using hematoxylin and eosin and Masson’s trichrome staining were conducted at 24 hours and 42 days, and HIF-1A was assessed using quantitative real-time polymerase chain reaction (qRT-PCR). At day 42, inflammation scores were numerically lower in the secretome group than in the control group, although the between-group difference was not statistically significant (0.00±0.00 vs 0.25±0.25; p=0.317). Fibrosis scores showed a similar numerical pattern without a significant difference (3.25±0.25 vs 3.50±0.29; p=0.495). Conversely, the secretome group exhibited numerically greater collagen area (79.93±11.11×10⁴ µm² vs 59.25±7.44×10⁴ µm²; p=0.149) and percentage collagen area (68.81±4.48% vs 56.07±3.29%; p=0.083), but neither difference reached statistical significance. HIF-1A expression was also numerically higher in the secretome group at day 42, without a statistically significant between-group difference (27.47±0.38 vs 26.44±0.54; p=0.149). Although the secretome group exhibited numerically lower inflammation and fibrosis scores and greater collagen deposition and HIF-1A expression, these differences were not statistically significant. Further adequately powered studies incorporating functional, histological, and molecular endpoints are required to clarify the regenerative potential of hypoxia-conditioned MSC secretome in anal sphincter injury.]]>
