THE EFFECT OF SURGICAL TRAUMA ON RAT TUNICA ALBUGINEA

Purpose: Increased TGF-beta 1 protein expression in tunica albuginea h as been found to be associated with Peyronie's disease. The present st udy is designed to investigate whether surgical trauma induces TGF-bet a up-regulation and histological changes in rat penis. Materials and M ethods: Thirty-two adult male Sprague-Dawley rats were divided into tw o groups. The first group (n = 24) underwent incision and suture repai r of the tunica albuginea of the penis. The second group (n = 8) recei ved sham surgery (incision of the penile skin and underlying fascia) a s the control group. The trauma-induced group was divided into four su bgroups in which the rats were euthanized at 6 hours (n = 6), 1 day (n = 6), 3 days (n = 6), and 8 weeks (n = 6). Two sham-operated (control ) animals were also euthanized at each of the above time points. All t unical tissues from the trauma-induced and sham-operated rats were col lected and examined histologically using Trichrome and Hart elastic fi ber stain. Electron microscopy was used to study the ultrastructural c hanges of both trauma induced and control specimens. Western blotting technique was performed to study TGF-beta protein expression in both e xperimental and sham-operated groups. Results: Tissue edema and hemorr hage between collagen bundles are noted in the experimental groups aft er 6 hours, 1 day and 3 days, At 8 weeks the most prominent changes ob served were inflammatory cellular infiltration and disorganization of the collagen bundles. in the control group the tunica albuginea retain s normal wavy regular appearance in all rats. This histological analys is is similar to the reported description of histological features of the acute phase of Peyronie's disease. Electron microscopy showed pack ed collagen bundles in the trauma-induced group with normal appearing elastic fibers. No abnormal change was detected in the control group. Immunoblot results revealed remarkable TGF-beta 1 protein expression i n 1, 5, 3, and 6 rats of trauma induced subgroups after 6 hours, 1 day , 3 days, and 8 weeks respectively. No TGF-beta 1 protein expression i n any rats in the control group was detected, No significant TGF-beta( 2) or TGF-beta(3) protein expression was observed either in the trauma induced group or in the control group, Conclusion: Trauma can induce histological changes similar to the acute phase of Peyronie's disease but not the overt picture of the chronic phase of Peyronie's disease. It can also result in an early but transient up-regulation of TGF-beta 1 protein expression in the rat penis. We conclude that surgical inci sional trauma does not result in Peyronie's disease-like changes in th e tunica.