Histological and immunohistochemical study on the protective effect of Ginkgo biloba extract against glutamate-induced neurotoxicity in male albino rat retinal cells

Monosodium glutamate [MSG] has a flavor-enhancing effect; hence, it is added to processed food. It is known for its neurotoxicity. This study was conducted to demonstrate the possible protective effect of the natural antioxidant, Ginkgo biloba extract, against the neurotoxicity of MSG on the retinal cells of male albino rats. Thirty adult male albino rats were used. The animals were divided into the following groups: group I was the control group and group II was subdivided into subgroup IIa, which received MSG injections for 7 days, and subgroup IIb, which received Ginkgo biloba [EGb 761] orally for 7 days and then received MSG injections, in addition to EGb. Retinal sections were stained with H and E stain, toluidine blue stain, and immunohistochemical staining for glial fibrillary acidic protein [GFAP]. Total retinal thickness, thickness of the outer nuclear layer, and the mean area% of GFAP were measured using an image analyzer. MSG caused complete loss of the outer and inner segments of the photoreceptors, a decrease in the thickness of the outer nuclear and plexiform layers, focal cytoplasmic vacuolation in the inner nuclear layer, and complete distortion of the ganglion cell layer. Such abnormalities were, to a large extent, prevented with the use of EGb 761. Statistically significant differences in the total retinal thickness, the thickness of the outer nuclear layer, and mean area% of GAP were found between the groups. MSG exposure was shown to induce deleterious morphological changes on the retina, many of which were prevented with the use of EGb 761. Thus, this natural extract could have further clinical implications in reducing glutamate-induced excitotoxicity in several ophthalmic diseases

Sildenafil citrate abuse [II]: an ultrastructural study of the long-term administration of sildenafil citrate in male albino rats

It has been reported that the most affected organs on abusing sildenafil citrate were the testis, retina, brain and heart; and that these changes were dose-and frequency-dependent. This study was set up to elucidate the ultra-structural alterations and hence the mechanism of toxicity in the retinal, cerebral, myocardial and testicular tissues which could result from administration of sildenafil citrate at a dose equivalent to the 100 mg tablet in humans administered at different frequencies. In addition, the study aimed at the assessment of the suitable dose and frequency of administration of the drug. Forty-eight male Wistar albino rats were used; and they were divided into: [n=12] negative control group. [n=36] rats received sildenafil citrate by gavage in a dose of 0.008 mg/g rat. This group was subdivided into 3 subgroups: [n=12] rats received the dose daily. [n= 12] rats received the dose day after day. [n= 12] rats received the dose once per week. The study extended for 18 weeks. Small portions from the brain, retina, heart and testes were excised and processed for electron microscopic examination. Sildenafil citrate causes histopathological alterations in the brain, retina, heart and testis in a dose-and time-dependent manner. It exerts its pathologic effects partly through persistent dilatation and thickening of t he blood vessel walls of the a forementioned tissues; and partly via direct action on the tissue cells and in particular on the mitochondria and rough endoplasmic reticulum

Sildenafil citrate abuse: [1] A histological multiple-dose study of the long-term administration of Viagra in male albino rats

Long-term adverse effects of sildenafil citrate [Viagra] have not been properly assessed. Consequently, this study aimed at evaluating the long-term alterations in different organs according to the dose and frequency of administration. To fulfill this aim, [132] male Wistar albino rats were studied for [18] weeks, and divided into [5]groups. Group [1] [n[=]12]: is the negative control group, Group [2] [n=12]: received distilled water; Group [3] [n=36]: received sildenafil [0.002 mg/g] and was subdivided into [3] subgroups: [a] received the dose daily=[b] received it day after day-[c] received it once weekly; Group [4] [n=36]; received sildenafil [0.004 mg/g] and was subdivided into [3] subgroups as group [3]; Group [5] n=36]; received sildenafil [0.008 mg/g] and was subdivided into 3 subgroups as groups [3] and [4]. Histological esamination of brain, retina, heart, lung, liver, kidney, prostate, seminal vesicles, epididymis and testis was performed using light microscopy for all the aforementioned organs. It was concluded that the testis and epididymis were the most affected organs. The retina then follows with disintegration of photoreceptors. The brain also showed congestion and increased astrocytic activity. As for the heart, it showed disarray and edema; while the lungs showed thickening of alveolar walls. The liver showed histological alterations, while the kidneys did not. All these histo-pathological alterations were observed to be dose-dependent and directly correlated to the frequency of sildenafil administration