RESUMEN
OBJECTIVE: To evaluate the impact of nicotine- and tar-free cigarette smoke extract (fCSE) on the serum testosterone (T) level and erectile function of male rats. METHODS: We randomized 30 male SD rats to three groups of equal number to receive subcutaneous injection of PBS (1.0 ml / 300 g body weight per day), fCSE (1.0 ml/300 g body weight per day), and reduced glutathione hormone (GSH, 200 mg per kg body weight per day) in addition to fCSE (fCSE + GSH), respectively, all for 8 weeks. Then we evaluated the erectile function of the rats by measuring the maximal intracavernous pressure (MICP), mean arterial pressure (MAP), ICP/MAP ratio, time of stimulation to MICP (Tmax), and cavernosal filling fate (CFR). We determined the serum T level, the activities of superoxide dismutase (SOD) , malondialdehyde (MDA), and nitric oxide synthase (NOS) in the cavernosal tissue, and also observed the morphological changes of the corpus cavernosum. RESULTS: Compared with the controls, the rats of the fCSE group showed obvious decreases in the levels of serum T ([5.37 ± 1.43] vs [3.22 ± 1.11] µg/L), NOS ([2.90 ± 0.27] vs [1.67 ± 0.18] U/mg) , and SOD ([18.41 ± 1.09] vs [13.36 ± 1.18] U/mg prot) and erectile function-related indexes MICP ([85.92 ± 6.36] vs [58.99 ± 10.76] mmHg), MICP/MAP (0.86 ± 0.09 vs [0.56 ± 0.08]), and CFR (2.14 ± 0.44 vs 0.89 ± 0.44), but markedly increased Tmax ([29.90 ± 5.78] vs [42.90 ± 8.56]s), with a positive correlation between the serum T level and CFR (r = 0. 364, P < 0.05). Masson staining revealed a lower ratio of the corpus cavernosum smooth muscle tissue to collagen fiber in the fCSE group (0.27 ± 0.04) than in the control (0.98 ± 0.12). Compared with the fCSE group, the fCSE + GSH group exhibited significantly improved MICP ([58.99 ± 10.76 ] vs [77.95 ± 7.71] mmHg), MICP/MAP (0.56 ± 0.08 vs 0.77 ± 0.09), and CFR (0.89 ± 0.44] vs 1.76 ± 0.42) and shortened Tmax ([42.90 ± 8.56 ] vs [32.10 ± 5.84 ] s). The ratio of the corpus cavernosum smooth muscle tissue to collagen fiber was higher in the fCSE + GSH than in the fCSE group (0.77 ± 0.09 vs 0.27 ± 0.04) but still lower than in the control (0.98 ± 0.12). CONCLUSION: Nicotine- and tar-free cigarette smoke extract reduces the serum T level and erectile function of rats, which is related to oxidative stress. Antioxidant therapy can improve erectile function but has a limited value for morphological protection of the penile tissue.