Oral l‐citrulline supplementation improves erectile function and penile structure in castrated rats

Abstract

Abbreviations & AcronymsObjectives: To investigate the efficacy of oral L-citrulline for erectile dysfunction and penile structure disruption in a rat model. Methods: Male Wistar-ST rats aged 15 weeks were randomly divided into three groups as follows: sham-operated rats (control group), surgically castrated rats (castrated group) and surgically castrated rats subsequently treated with 2% L-citrulline water (castrated + Lcitrulline). At 4 weeks postoperative, erectile function was assessed based on intracavernous pressure changes, followed by electrostimulation of cavernous nerves and calculation of maximum intracavernous pressure/mean arterial pressure. Penile structure was evaluated by Masson's trichrome staining and the smooth muscle-to-collagen ratio was calculated. The serum bioavailable testosterone, L-arginine, L-citrulline, N G ,N G -dimethylarginine and nitrogen oxide levels were evaluated. Results: The bioavailable testosterone concentrations were decreased in the castrated and castrated + L-citrulline groups compared with the control group at 4 weeks after surgery. The intracavernous pressure-to-mean arterial pressure and smooth muscle-to-collagen ratios were significantly decreased in the castrated group compared with the control group, but significantly increased in the castrated + L-citrulline group compared with the castrated group. The serum L-citrulline, L-arginine and N G ,N G -dimethylarginine levels, and the L-arginineto-N G ,N G -dimethylarginine ratios were significantly increased in the castrated + L-citrulline group compared with the castrated group. The serum nitrogen oxide levels were increased in the castrated + L-citrulline group compared with the castrated group. Conclusions: Oral L-citrulline can improve the erectile response to electric stimulation of cavernous nerve and penile structure in castrated rats.

Molecular and Histologic Evidence of Novel Erectile Dysfunction Rat Model as an Aging Atherosclerosis Model: A Preliminary Study

“…The key pathophysiology of AS change lies in obstructing arterial inflow by narrowed lumen due to artherosclerotic lesions [1,4,10,17,18]. Hence, without intimal injury, an ED model could not show endothelial dysfunction.…”

“…In this change, TGF-β plays an important role [4,5]. Among previous studies, arterial ligation or partial obstruction was a good model to show structural change [4,5,10]. However, these studies did not try to show functional change associated with endothelial dysfunction.…”

“…Currently, there is limited report on such effort. Moreover, there exist difficulties regarding feasibility and reproducibility of such model in the literature [3][4][5][6][7][8][9][10]. Furthermore, reported models have limitations including no endothelial dysfunction unless genetic modification or a special diet is required to evoke endothelial injury.…”

Castration impairs erectile organ structure and function by inhibiting autophagy and promoting apoptosis of corpus cavernosum smooth muscle cells in rats

“…Many studies have reported that the erectile response to cavernous nerve electrostimulation in castrated rats was significantly reduced compared with normal rats [18,[34][35][36]. By surgical castration and T replacement, we established rat models with different testosterone concentrations and basal erectile function.…”

Translational Perspective on the Role of Testosterone in Sexual Function and Dysfunction

“…Testosterone may impact corpora cavernosal tissues by decreasing neuronal and endothelial NOS in the corporal beds [82, 83]. Other studies have suggested that metabolic supplements may help maintain erectile response and mating behaviors in animal models of castration or aging through the actions of Tuarine and l-Citrulline focusing on the role of maintenance of the NO signaling pathway [84, 85]. …”