Astaxanthin mitigates radiation-induced erectile dysfunction: protective effects on corpus cavernosum in a rat model

The objective of this study was to evaluate the effects of ionizing radiation (iR) on corpus cavernosum and the potential of astaxanthin (AST) in preventing radiation-induced erectile dysfunction (RiED). Male Wistar Albino rats (10-12 week, 250-300 g) were divided-into four groups: sham (SH, n = 8), radiotherapy (RT, n = 8), vehicle-administered (olive oil (OO); RT + OO, n = 12), and astaxanthin (RT + AST, n = 12). The RT-group received 12-Gy prostate-targeted iR. The vehicle-administered (OO) group received iR with daily 1 ml OO via oral gavage, while the AST-group received iR with 50 mg/kg AST dissolved in OO. After the treatment-period (12-week), intracavernosal pressure to mean arterial pressure (ICP/MAP) ratios in the RT [0.28(0.14-0.65)] and OO groups [0.26(0.19-0.64)] were significantly lower than in the SH [0.6(0.43-0.72)] and AST [0.53(0.35-0.64)] groups (p < 0.05). iR caused narrowing of the cavernous sinusoids (RT:95.38 (84.62-110.05) vs SH:132.33 (113.27-155.86), AST:124.44 (112.11-131.97) µm, p < 0.001). Alpha smooth muscle actin (SH:165 (136.25-188.75) vs RT:100 (87.5-112.5), AST:137.5 (107.5-155), p < 0.001), endothelial nitric-oxide synthase (NOS) (SH:127.5 (115-167.5) vs RT:92.5 (81.25-98.75), AST:115 (86.25-128.75), p = 0.002) and neuronal NOS (SH:152.5 (133.75-163.75) vs RT:95 (81.25-103.75), AST:135 (125-140), p < 0.001) were diminished in the RT-group and preserved in the AST-group according to immunohistochemical scoring. Biochemical measurements of the corpus cavernosum revealed that the level of cGMP was significantly higher (93.15 (71.22-103.38) vs 70.8 (65-72.35) pmol/ml) in the AST-group, while lipid peroxidation was significantly higher (32.38 (29.07-36.98) vs 20.14 (17.85-21.04) nmol.mda/g) in the RT-group (p = 0.004, p < 0.001). This trial showed that AST preserved ICP/MAP values and histopathological-biochemical parameters after exposure to iR.