sildenafil-citrate and Atrophy

Non-union formation represents a major complication in trauma and orthopedic surgery. The phosphodiesterase-5 (PDE-5) inhibitor sildenafil has been shown to exert pro-angiogenic and pro-osteogenic effects in vitro and in vivo. Therefore, the aim of the present study was to analyze the impact of sildenafil in an atrophic non-union model in mice. After creation of a 1.8 mm segmental defect, mice femora were stabilized by pin-clip fixation. Bone regeneration was analyzed by means of X-ray, biomechanics, photoacoustic and micro-computed tomography (µCT) imaging as well as histological, immunohistochemical and Western blot analyses at 2, 5 and 10 weeks after surgery. The animals were treated daily with either 5 mg/kg body weight sildenafil (n = 35) or saline (control; n = 35) per os. Bone formation was markedly improved in defects of sildenafil-treated mice when compared to controls. This was associated with a higher bending stiffness as well as an increased number of CD31-positive microvessels and a higher oxygen saturation within the callus tissue. Moreover, the bone defects of sildenafil-treated animals contained more tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts and CD68-positive macrophages and exhibited a higher expression of the pro-angiogenic and pro-osteogenic markers cysteine rich protein (CYR)61 and vascular endothelial growth factor (VEGF) when compared to controls. These findings demonstrate that sildenafil acts as a potent stimulator of angiogenesis and bone regeneration in atrophic non-unions.

Topics: Animals; Atrophy; Bone Regeneration; Cyclic Nucleotide Phosphodiesterases, Type 5; Mice; Phosphodiesterase 5 Inhibitors; Sildenafil Citrate; Vascular Endothelial Growth Factor A; X-Ray Microtomography

The commonly utilized phosphodiesterase type 5 inhibitors do not lead to satisfactory penile erection after radical prostatectomy mainly because of insufficient nitric oxide drive from the damaged cavernous nerves. The aim of this study was to assess the efficacy and mechanisms of icariin in combination with daily sildenafil on neurogenic erectile dysfunction and penile atrophy in a rat model of bilateral cavernous nerves injury. Sixty male Sprague-Dawley rats injected with 5-ethynyl-2-deoxyuridine (50 mg/kg) at postnatal day 1 for the purpose of tracking endogenous stem cells in penis. Forty-eight rats of bilateral cavernous nerves injury were randomized equally into gavage feeding of vehicle, sildenafil (10 mg/kg), icariin (1.5 mg/kg) and sildenafil + icariin, respectively. Twelve sham-operated rats served as control. The intracavernous pressure and mean arterial pressure was measured and mid-penile cross sections were histologically examined 5 weeks after surgery. Western blotting of cavernous tissue protein was also performed. Animals treated with sildenafil + icariin had significantly higher mean intracavernous pressure/mean arterial pressure ratio relative to other rats with bilateral cavernous nerves injury (p < 0.05). The circumference and mean cross-sectional area of the paired corpus cavernosum were effectively preserved in the sildenafil + icariin. Treatment with sildenafil + icariin significantly increased the cavernous cyclic guanosine monophosphate concentration compared with the icariin group (p < 0.05). In addition, the numbers of neuronal nitric oxide synthase-positive nerves and 5-ethynyl-2-deoxyuridine-positive cells co-expressing S100 in the icariin-treated groups were greater compared with the bilateral cavernous nerves injury control group (p < 0.05). These data suggest that the combined use of icariin and daily sildenafil holds promise as a potential therapy for neurogenic erectile dysfunction in the future. The underlying mechanisms appears to involve two aspects: (i) icariin promotes differentiation of endogenous stem cells to Schwann cells, which help to repair the damaged neural pathway for erection; (ii) on this basis, sildenafil can further improve penile engorgement through the cyclic guanosine monophosphate-dependent smooth muscle relaxation.

Topics: Animals; Atrophy; Blotting, Western; Disease Models, Animal; Erectile Dysfunction; Flavonoids; Fluorescent Antibody Technique; Male; Penile Erection; Penis; Prostatectomy; Rats; Rats, Sprague-Dawley; Sildenafil Citrate

Nitric oxide synthases (NOSs) and estrogen receptors are expressed in the vagina.. We aimed to assess the impact of sildenafil on vaginal lubrication according to the hormonal status and to determine the role of the neuronal isoform of NOS (nNOS).. Four-week-old C57/BL6 female mice were sham operated or ovariectomized. At 10 weeks of age, they were injected intraperitoneally by any combination of sildenafil, 7-nitroindazole (7-NI)--a potent selective nNOS inhibitor--or the corresponding vehicles. Vaginal lubrication was induced in a physiological manner by cervical vaginal probing and quantified depending on the hormonal and pharmacological conditions. The animals were then sacrificed for vaginal histomorphometry.. The main outcome measure is the quantification of vaginal transudate after cervicovaginal stimulation and vaginal histomorphometry.. Sildenafil increased cervicovaginal probing-induced vaginal lubrication in ovariectomized and sham-operated animals. Ovariectomized mice exhibited decreased vaginal lubrication as compared with sham-operated mice. When taking into account the presence of severe vaginal atrophy, a threefold increase in transudate per gram of vagina wet weight was revealed in ovariectomized animals. Castration markedly reduced the thickness of the vaginal wall. nNOS inhibition by 7-NI had no impact on vaginal lubrication.. Irrespective of the hormonal status, sildenafil increased vaginal lubrication. The vaginal effect of sildenafil was independent of the nNOS pathway and more pronounced in ovariectomized animals.

Topics: Animals; Atrophy; Enzyme Inhibitors; Exudates and Transudates; Female; Indazoles; Mice; Mice, Inbred C57BL; Nitric Oxide Synthase Type I; Ovariectomy; Phosphodiesterase 5 Inhibitors; Physical Stimulation; Piperazines; Purines; Sildenafil Citrate; Sulfones; Vagina

Topics: Adjuvants, Immunologic; Adult; Antidepressive Agents, Second-Generation; Atrophy; Benzimidazoles; Bupropion; Clinical Trials, Phase III as Topic; Dehydroepiandrosterone; Dopamine Uptake Inhibitors; Female; Gels; Humans; Libido; Male; Middle Aged; Phosphodiesterase Inhibitors; Piperazines; Placebos; Postmenopause; Purines; Sexual Dysfunctions, Psychological; Sildenafil Citrate; Sulfones; Testosterone; United States; United States Food and Drug Administration; Vagina; Vasodilator Agents