Evaluation of extracellular matrix protein composition in sacs associated with undescended testis, hydrocele,...

To investigate and compare the distribution and intensity of staining of extracellular matrix proteins--laminin, fibronectin, and types 1 and 4 collagen--in various congenital inguinoscrotal abnormalities and the peritoneum through immunohistochemical staining.

The sacs associated with undescended testis (n = 28), hydrocele (n = 29), inguinal hernia (n = 31), and parietal peritoneum (n = 28) were stained with antibodies for laminin, fibronectin, and types 1 and 4 collagen. The peritoneum served as the control group. Appropriate tissue sections of each group of samples were identified and compared with regard to the intensity and distribution of staining.

The expression of laminin was significantly greater in the sacs associated with undescended testes and inguinal hernia than in the peritoneum. The expression pattern of fibronectin did not differ in the sacs of the different inguinoscrotal abnormalities compared with peritoneum. Type 1 collagen was strongly expressed in the sacs obtained from the hydroceles compared with the other groups and the peritoneum. Expression of type 4 collagen was significantly increased in the sacs associated with hydrocele and inguinal hernia compared with the peritoneum.

The distribution and expression of laminin and types 1 and 4 collagen showed variability in the sacs associated with undescended testis, hydrocele, and inguinal hernia and the peritoneum. The tensile forces that the sacs associated with childhood inguinoscrotal abnormalities are exposed to per se could account for some of the differences seen between the inguinoscrotal tissues and anterior peritoneum. These differences in the extracellular matrix proteins could also reflect congenital properties of various childhood inguinoscrotal abnormalities.