Effects of buried penis on the structure and function of corpus cavernosum in a rat model

Background While the abnormal appearance of the concealed penis has been well recognized, the effect of buried penis on the structure and function of corpus cavernosum has not been well studied. To explore this issue, we established a rat model and evaluated the effect of buried penis on cavernosum weight, contents and ultrastructure of tissue, and nitric oxide synthase （NOS） activity. Methods Two hundred and ten rats were randomly divided into 3 equal cohorts for 2, 4 and 6 months study （groups A, B and C）. Each group was randomly divided into buried group （n=40）, control group （n=15）, and normal group （n=15）, respectively. Intra-purse-string suture of the root of the penis was used to establish the model. Macroscopic development was judged by measuring the weight of the corpus cavernosum. Masson＇s trichrome staining was performed for observing microstructure while a transmission electron microscope was used for observing ultrastructure. The NOS activity was detected by a NOS activity assay kit. Results Buried penis had no significant influence on the appearance and weight of the corpus cavernosum. Buried penis resulted in decreased smooth muscle content （P 〉0.05 in group A, and P 〈0.05 in groups B and C） and increased fibrous connective tissue content （P 〉0.05 in groups A and B, and P 〈0.05 in group C） compared with the normal and control groups. Ultrastructural abnormalities of corpus cavernosum were observed in the 6-month buried group. Moreover, there was decrease of NOS activity in groups B and C （P 〈0.05 in group B and P 〈0.01 in group C） when compared with the normal and control groups. Conclusion Buried penis affects the structure and function of corpus cavernosum in rats and the effect is positively correlated with the buried time, but there is no significant effect on the macroscopic development.