Assessing the potential regeneration ability of corpus spongiosum in rabbit models

Most congenital or acquired urethral diseases are usually accompanied by corpus spongiosum (CS) defects. However, Substitution urethroplasty can only reconstruct urethral lumen, not the CS. Many long-term complications occur due to the lack of protection from CS. Is CS a kind of tissue that cannot be repaired by regeneration and self-healing? In this study, the CS defect with urethral mucosa intact model was established in rabbits by removing the ventral CS tissue. Based on this model, three groups of different CS defect sizes, with lengths of 0.5 cm (Group A), 1.0 cm (Group B) and 1.5 cm (Group C), were then constructed, respectively, to assess the potential regeneration ability of CS. Three months later, the entire urethra, including the CS defect, was assessed by histological staining. Results showed that the vascular sinusoids were completely removed from urethral mucosa. The rabbit model of CS defect was established successfully. Three months post-operatively, the CS defects in all the 3 groups were replaced by disordered collagen instead of regenerating typical sinusoid-like vascular structure, which is significantly different from the normal CS rich in vascular sinusoids. The CS defects could not be repaired through self-healing. The potential regeneration ability of CS is extremely poor.