Eltony Sohair A, Abdelhameed Sally Y
Histology and Cell Biology Department, Faculty of Medicine, Assiut University, Egypt.
Forensic Medicine and Clinical Toxicology Department, Faculty of Medicine, Assiut University, Egypt.
Tissue Cell. 2017 Apr;49(2 Pt B):323-335. doi: 10.1016/j.tice.2017.01.006. Epub 2017 Feb 5.
Abnormal vision has been reported by 3% of patients treated with sildenafil citrate (Viagra). Although many men use Viagra for an extended period for treatment of erectile dysfunction, the implications of the long term-daily use of it on the retina and optic nerve are unclear.
To investigate the effect of chronic daily use of sildenafil citrate in a dose equivalent to men preferred therapeutic dose on the histology of the retina and optic nerve of adult male rat.
MATERIAL & METHODS: Eighteen adult male Wistar rats were equally divided into three groups. Group I: control. Group II: treated with sildenafil citrate orally (10mg/kg/day) for 8 weeks. Group III (withdrawal): treated as group II and then left for 4 weeks without treatment. Specimens from the retina and optic nerve were processed for light and electron microscopy.
In sildenafil citrate treated group, the retina and optic nerve revealed vacuolations and congested blood capillaries with apoptotic endothelial and pericytic cells, and thickened basal lamina. Caspase-3 (apoptotic marker) and CD31 (endothelial marker) expression increased. Glial cells revealed morphological changes: Müller cells lost their processes, activated microglia, astrocytic clasmatodendrosis, degenerated oligodendrocytes surrounded by disintegrated myelin sheathes of the optic nerve fibers. The retina and optic nerve of the withdrawal group revealed less vacuolations and congestion, and partial recovery of the glial cells.
Chronic treatment with sildenafil citrate (Viagra) caused toxic effect on the structure of the retina and optic nerve of the rat. Partial recovery was observed after drug withdrawal.
据报道，3%接受枸橼酸西地那非（伟哥）治疗的患者出现了视力异常。尽管许多男性长期使用伟哥治疗勃起功能障碍，但其长期每日使用对视网膜和视神经的影响尚不清楚。
研究以相当于男性首选治疗剂量的枸橼酸西地那非每日长期给药，对成年雄性大鼠视网膜和视神经组织学的影响。
18只成年雄性Wistar大鼠平均分为三组。第一组：对照组。第二组：口服枸橼酸西地那非（10mg/kg/天）8周。第三组（撤药组）：同第二组处理，然后停药4周。对视网膜和视神经标本进行光镜和电镜检查。
在枸橼酸西地那非治疗组，视网膜和视神经出现空泡形成、毛细血管充血，伴有内皮细胞和周细胞凋亡，基膜增厚。半胱天冬酶-3（凋亡标志物）和CD31（内皮标志物）表达增加。神经胶质细胞出现形态学改变：穆勒细胞失去突起，小胶质细胞活化，星形胶质细胞分支断裂，少突胶质细胞变性，视神经纤维髓鞘崩解。撤药组的视网膜和视神经空泡形成和充血较少，神经胶质细胞部分恢复。
枸橼酸西地那非（伟哥）长期治疗对大鼠视网膜和视神经结构产生毒性作用。停药后观察到部分恢复。
