Research On Risk Factors Of Hypospadias And Corpus Spongiosum Defect Repair

Objective:First,to explore the risk factors of hypospadias.Second,the void-forming photosensitive hydrogel encapsulated with USC-s EVs was applied to repair the corpus spongiosum defect in rabbit model.Materials and methods:Part 1,a retrospective cohort study on neonatal hypospadias was established from January 2015 to December 2019 to assess the risk factors for neonatal hypospadias.Part 2,in order to explore the regenerative potential of corpus spongiosum tissue,we first established the rabbit model of corpus spongiosum defect through resecting partial ventral corpus spongiosum tissue,and evaluated the regenerative capacity of corpus spongiosum by constructing three types of corpus spongiosum defects with different lengths（0.5 cm,1.0 cm and 1.5 cm）.Part 3,USC-s EVs of different concentrations(0,10⁷/m L,10⁸/m L,10⁹/m L,10¹⁰/m L)were used to intervene HMEC-1 and SMCs in vitro to verify its pro-angiogenesis function.Part 4,on the basis of this animal model,we further applied a void-forming photosensitive hydrogel encapsulated with USC-s EVs to repair the encapsulated defect.The animals were divided into four groups,including v HG-s EVs group,HG-s EVs group,v HG group and blank control group.Histological staining at 1 and 3m postoperatively was used to evaluate the therapeutic effect.Results:Part 1,a total of 41488 mothers were enrolled,of whom 97 cases had newborns with hypospadias.The total incidence of hypospadias was 0.23%.The results of statistical analysis showed that gestational hypertension could significantly increase the incidence of hypospadias（P<0.01）.Maternal hyperthyroidism and low birth weight were also significantly correlated with hypospadias.Part 2,histological results showed that the typical vascular sinusoids were completely removed,which meant the rabbit model of corpus spongiosum defect was successfully established.Three months after operation,histological results showed that all the three groups were filled with fibrous tissue and lack of normal sinusoid structure.Part 3,USC-s EVs can significantly promote the proliferation,migration and tube forming capabilities of HMEC-1,and also significantly enhance SMCs’proliferation and migration capabilities.Part 4,the void-forming photosensitive hydrogel has good biocompatibility and can play the role of sustained-release USC-s EVs.In v HG-s EVs and HG-s EVs group,the corpus spongiosum defects were significant repaired,and the therapeutic effect of v HG-s EVs group were better than that of HG-s EVs group.But in the v HG and blank control group,there was no regeneration of sinusoid like structure replaced by dense fibrous tissue.Conclusion:First,gestational hypertension,hyperthyroidism and low birth weight are important risk indicators of hypospadias in China.Second,the regeneration capacity of corpus spongiosum is very poor.The rabbit model of corpus spongiosum defect established in this study is suitable for studying the regenerative ability of corpus spongiosum tissue.Third,the v HG-s EVs tissue patch can significantly promote the regeneration of corpus spongiosum.