Retinal function depends on light trapping. However, continuous exposure to light may cause damage to the highly vulnerable retinal structure. Aim of the study This study aimed to investigate the possible histological alterations that might occur in the retinal neurons as a result of continuous exposure to fluorescent light in adult male albino rats. Materials and methods Ten healthy adult male albino rats were equally divided into two groups: a control group and a light-exposed group. Rats of control group were kept in 12 h light/12 h dark for 12 weeks. Rats of light-exposed group were put in top-opened cages illuminated by white fluorescent bulbs continuously for 1 week and then were kept in 12 h light/12 h dark for the following 11 weeks. The retina was extirpated and processed for examination by light and electron microscopy. The thickness of outer nuclear, inner nuclear, outer plexiform, and inner plexiform layers was estimated morphometrically and was statistically analyzed. ResultsFluorescent light-exposed neural retina revealed that photoreceptor outer segments were markedly disorganized and inner segments were short and less condensed. Outer nuclear layer contained few photoreceptors with marked intercellular spaces. Inner nuclear layer showed wide spaces between its neurons, with some of them having shrunken nuclei and others having disintegrated nuclei. Mü ller cells with deeply stained bodies and processes were seen in inner and outer nuclear layers. Many ectopic neurons were detected in the inner plexiform layer. Ganglion cell layer mostly contained deeply stained glial cells and few ganglion neurons. Nerve fiber layer showed an apparent increase in thickness. The estimated and analyzed thickness of the outer nuclear, inner nuclear, outer plexiform, and inner plexiform layers confirmed the results. ConclusionContinuous exposure to fluorescent light triggered retinal remodeling, including neuronal loss, reactive gliosis with neuronal and glial cells migration. This may lead to visual impairment.

Introduction: Stem cell-based therapies have the potential effectivity in many human diseases including retinal disorders. They have been proven to be safe and effective in a wide range of immune-mediated diseases. Aim of the work: To investigate the effectiveness of ADMSCs in the prevention of retinal damage after induction of diabetes. Material and methods: Forty adult male rats were divided into three groups; Group I: subdivided into negative and positive control. Group II: received a single intraperitoneal injection of STZ (50 mg/kg), freshly dissolved in 0.9% saline solution. Blood glucose levels were measured two days after STZ injection, and rats with glucose levels ≥ 250 mg/dl were considered diabetic and used in the study. Group III: received STZ, in the same previous dose, then the diabetic rats were injected intravenously with 0.5 ml ADMSCs (1×10 7 cells/ml) suspended in phosphate-buffered saline. After four weeks, retinal specimens were prepared for histological and immunohistochemical studies. Results: The retina of STZ-treated group showed poorly-developed basal infoldings of RPE cells, distorted lamellar discs of photoreceptor outer segments, loss of cellular elements in the outer nuclear layer, inner nuclear layer and ganglion cell layer, and apoptosis. After ADMSCs administration, there was improvement in the retinal structure. There was highly significant decrease in the area percent of caspase-3 in cells of all retinal layers, compared to the diabetic group, and no difference was found when compared with the control group. Conclusion: ADMSCs was proved to be effective in the prevention of retinopathy in experimentally-induced diabetic rat model. This might represent a valuable tool for stem cell-based therapy in the future.

No abstract

Background: Human is daily exposed to electromagnetic field from different source in modern societies with associated health impacts. This experiment aims to study the histological structure of parotid gland after exposure to extremely low frequency magnetic field ELF-MF associated with utility grid 50/60 Hertz (Hz) and to detect the possible role of Vitamin E supplementation.

Background: Silver nanoparticles (Ag-Nps) and Titanium dioxide nanoparticles (TiO2-Nps) are well-known nanoproducts. Both of them have many industrial applications. Lung is one of the major target organs for prolonged nanoparticles exposure. Objective: This study was designed to investigate and compare the possible histopathological toxic effect of Ag-Nps & TiO2-Nps on lung and which of them is safer for future using. Materials & methods: 54 adult male albino rats were divided into 3 equal groups; GroupI (control group), Group II that subdivided into two subgroups; Subgroup IIa: Ag-Nps group with (100 mg/kg/day) daily for 4 successive weeks and Subgroup IIb recovery group left for 4 weeks without injection, Group III that subdivided into two subgroups; Subgroup IIIa: TiO2-Nps group with (150 mg/kg/day) for 4 successive weeks and Subgroup IIIb recovery group left for 4 weeks without injection. Lung specimens were processed for light and electron microscope and immunohistochemical expression of caspase-3 and CD-68. Morphometric and statistical analysis were performed. Results: Group IIa showed collapsed alveoli, others showed ballooned distension and marked thickening of inter-alveolar septa. Extensive cellular infiltration was detected. Group IIIa showed focal areas of collapsed alveoli and thick inter-alveolar septa. Mild cellular infiltrations were observed. Areas of extravasation were detected in the interstitium. Group IIIb showed signs of improvement which is more than group IIb. Conclusion: exposure to Ag-Nps showed marked alterations on histological structure of lung, which is more than the alteration caused by TiO2-Nps; in addition, recovery period was proved to ameliorate these changes better in TiO2-Nps.