Effect of uncultured adipose-derived stromal vascular fraction on preventing urethral stricture formation in rats

Urethral stricture (US) remains a challenging disease without effective treatment options due to the high recurrence rate. This study aims to evaluate the preventive effect of uncultured adipose derived stromal vascular fraction (SVF) on urethral fibrosis in a rat model of US. Results demonstrated that US rats displayed hyperechogenic urethral wall with a narrowed lumen compared with sham rats, while SVF rats exhibited less extensive urethral changes. By histology, US rats showed obvious submucosal fibrosis in the urethral specimens, while SVF rats exhibited mild submucosal fibrosis with less extensive tissue changes. Furthermore, US rats showed increased gene and protein expression of collagen I (2.0 +/- 0.2, 2.2 +/- 0.2, all were normalized against GAPDH, including the following), collagen III (2.5 +/- 0.3, 1.2 +/- 0.1), and TGF beta 1R (2.8 +/- 0.3, 1.9 +/- 0.2), while SVF cells administration contributed to decreased gene and protein expression of collagen I (1.6 +/- 0.2, 1.6 +/- 0.2), collagen III (1.8 +/- 0.4, 0.9 +/- 0.1), and TGF beta 1R (1.8 +/- 0.3, 1.3 +/- 0.2), in parallel with the improvement of vascularization and increased expression of VEGF (1.7 +/- 0.1) and bFGF (3.1 +/- 0.3). Additionally, SVF served anti-inflammatory effect through regulation of inflammatory cytokines and cells, accompanied with conversion of the macrophage phenotype. Our findings suggested that uncultured SVF presented an inhibitory effect on stricture formation at an early stage of urethral fibrosis.

Automated summary

This study evaluated the preventive effect of uncultured adipose derived stromal vascular fraction (SVF) on urethral fibrosis in a rat model of urethral stricture (US). The results demonstrated that SVF administration reduced the extent of urethral changes and fibrosis, as well as decreased the expression of collagen and TGF beta 1R, while increasing vascularization and the expression of VEGF and bFGF. Additionally, SVF exerted anti-inflammatory effects and modulated macrophage phenotype. These findings suggest that uncultured SVF has an inhibitory effect on stricture formation in the early stage of urethral fibrosis.