Rat as an animal model for Peyronie's disease research: a review of current methods and the peer-reviewed literature

Abstract

While the exact mechanism of Peyronie's disease (PD) remains an enigma, the pathophysiology of PD is considered to be multifactorial, with interactions of genetic predisposition, trauma, tissue inflammation and aberrant wound healing. A non-systematic review of the existing English language literature pertaining to the use of rodent models in the evaluation of PD was performed using the Medline database. Multiple free-text searches were performed on key words: animal models of PD, transforming growth factor b1 (TGF b1), tunical and/or corporal fibrosis, subtunical injection and penile myofibroblasts. The most frequently reported models of PD can be classified as TGF b1, fibrin and surgical trauma-induced models. In vitro studies using Peyronie's fibroblast culture media have also provided further insights into cellular mechanism of PD. At the present time, the research in PD is hampered by the lack of universally accepted animal model and this is likely attributed to the limited insight into PD mechanisms and the difficulties faced by current animal models to truly represent the complexity and complete spectrum of human disease.

Experimental Models and Laboratory Research for Peyronie’s Disease

“…As suggested by Chung, the persistence of fi brin elicits an acute and, later, a chronic infl ammatory response and subsequent production of profi brotic factors (TGF-β1), and reactive oxygen species induce the development of the fi brotic plaque [ 8 ]. In 1997, Somers and coworkers, by using an experimental model on plaque tissue specimens, found that deposition of fi brin in plaque tissue is consistent with the hypothesis that repetitive microvascular injury results in fi brin deposition in the tissue space and has served to provide insights into the pathophysiology of Peyronie's disease [ 5 ].…”

“…Fibrin is an effective chemoattractant and chemotactic factor and promotes ingrowth of infl ammatory cells, macrophages, and fi broblast and induces collagen synthesis by fi broblast [ 8 ]. In 2003, Davilla et al by using a new animal model for PD found that fi brin, when introduced into the tunica albuginea of the rat penis, acts as a potential profi brotic protein, possibly via the local release of TGF-β1, and induces a plaque not only histologically similar to that induced by TGF-β1 but to that of the human condition [ 3 ].…”

“…In this sense, a signifi cant role should be attributed to fi brinogen/fi brin action. The mechanism of excessive deposition of fi brin is attributed to the persistence fi brin deposition due to unmasking of fi brinolytic enzymes by other plasma proteins and/or defi ciency of fi brinolytic enzymes [ 8 ].…”

“…The current animal models on PD are based predominantly on rats due to the fact that (1) the anatomy of the rat penis has been extensively described and this model has suffi ciently demonstrated similar morphological and functional characteristics to humans and (2) they are more economical to purchase, house, maintain, and dispose off compared with larger animals [ 8 ].…”

Repeated Micro-Trauma of the Penile Tunica Albuginea: A New Animal Model of Peyronie's Disease

“…Although the anticoagulation is added in, fibrin is still very easy to be freezing. Hence, using a small needle to inject fibrin is extremely difficult [26]. Some researchers induced rats spontaneously forming PD using the gene mutation technology.…”