Morphological study of retinal neurons after continuous exposure to fluorescent light in adult male albino rats

Retinal function depends on light trapping. However, continuous exposure to light may cause damage to the highly vulnerable retinal structure. 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. 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/1 2 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. Fluorescent light-exposed neural retina revealed that photoreceptor outer segments were markedly disorganized and inner segments were short and less condensed. Outer nuclear layer containeo 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. Muller 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. Continuous exposure to fluorescent light triggered retinal remodeling, including neuronal loss, reactive gliosis with neuronal and glial cells migration. This may lead to visual impairment

histological study of ipsilateral testis after experimentally induced varicocele in albino rats and the role of L-carnitine supplementation

Varicocele pathophysiology and its role in male infertility are still unclear. Varicocelectomy is not an effective treatment in such cases as it failed to restore fertility after surgery in many patients. The aims of this study were to investigate the histological alterations that might occur in the structure of the ipsilateral testis after experimental varicocele, to determine whether this effect was time dependent, and to evaluate the possible role of L-carnitine on the varicocele. Thirty-six young adult albino rats were used. They were equally divided into three groups. Group 1 was the control. Group 2 was the experimentally induced varicocele [EV] that was subdivided into two subgroups, EV6 and EV18, according to varicocele duration. Group 3 [EV-carnitine] was the experimentally induced varicocele left for 18 weeks followed by an intraperitoneal injection of 200 mg/kg L-carnitine [three times/week] for another successive 8 weeks. At the end of the experiment, the ipsilateral testes were extirpated and processed for light and electron microscope examinations. Epithelial height was estimated morphometrically and statistically analyzed. Testes of EV6 showed many distorted seminiferous tubules with irregular outlines, wide lumina, and disorganized epithelium including separation, sloughing, and multinucleated cells. Some areas of interstitium were wide. Acidophilic hyaline material was present in most of the interstitial spaces. Most of the tubules of EV18 were markedly distorted and were mostly lined by sertoli cells with a few spermatogenic cells. The tubular basement membrane of EV6 was relatively thick, irregular, and highly infolded and these changes were extremely obvious in EV18. Myoid cells appeared with irregular heterochromatic nuclei in EV18. Almost all sperm mid pieces in EV6 were markedly affected and no sperms were detected in most of the seminiferous tubules of EV18. Leydig cells in both subgroups showed variable-size electron-dense granules and cytoplasmic processes, which were more obvious in EV18. EV-carnitine nearly regained the normal architecture but a few tubules had a disorganized epithelium, a few affected sperms, and acidophilic hyaline material between some tubules. Leydig cells contained numerous mitochondria, a few variable-size electron-dense granules, a few lipid droplets, and no cytoplasmic processes. Estimation of epithelial height, which was statistically analyzed, confirmed the results. Varicocele led to a deleterious effect on the ipsilateral testis that increased progressively with time. L-Carnitine supplementation improved the structure of testis of long-duration varicocele

Histological study of the effect of melatonin against cyclosporine-a induced nephrotoxicity in adult male albino rats

Fifteen healthy adult male albino rats were used in this study aiming to demonstrate the histological changes that may occur in the renal cortex following cyclosporine-A therapy and to what extent melatonin could prevent these structural alterations. The animals were divided equally into three groups [5 animals each]. Group I; served as a control. Group II; animals were injected subcutaneously with cyclosporine-A at a dose of 15 mg/kg body weight daily for successive 4 weeks. Group III; animals received 1mg/kg body weight melatonin orally simultaneous with cyclosporine-A. At the time of sacrifice, all the animals were anaesthetized with ether inhalation and their kidneys were carefully dissected out and processed for examination by light and electron microscopes. By light microscope examination, the renal cortex of the cyclosporine-A treated animals showed the presence of many distorted renal corpuscles with condensed and deeply stained glomeruli. The renal glomeruli appeared with disorganized glomerular capillary loops. These loops attained ill-defined outlines and were separated by a pale stained mesangial substance. Some renal cortical convoluted tubules showed vacuolated epithelial lining. Ultrastructurally, the podocytes appeared with irregular electron dense nuclei. Their foot processes were distorted and fused. Also, the fenestrations of the glomerular endothelium and the blood renal barrier were distorted. The mesangial cells contained irregular nuclei with much heterochromatin. The epithelial cells lining both types of the renal cortical convoluted tubules showed loss of their basal infoldings and the mitochondria appeared rounded and scattered throughout their cytoplasm. Also, these cells appeared with much heterochromatic nuclei. Electron dense granules were seen in the cytoplasm of the epithelial cells lining some of the affected proximal convoluted tubules. A thick interstitium was noticed between some affected renal cortical convoluted tubules. On the other hand, light microscope observation of the renal cortex of the animals treated with melatonin concomitant with cyclosporine-A revealed the presence of few distorted renal corpuscles. Some glomerular capillary loops appeared with ill-defined outlines. The renal cortical convoluted tubules exhibited their normal epithelial lining. Ultrastructural examination of the same group revealed the podocytes of the renal corpuscles with well defined primary and secondary foot processes with preserved pores between the secondary ones. The fused basal laminae of podocytes and endothelium lining glomerular capillaries [blood renal barrier] showed thickening and interruption in some areas with absence of the endothelial fenestrations. The epithelial cells lining both proximal and distal convoluted tubules showed basal infoldings and elongated mitochondria. In conclusion, the simultaneous administration of melatonin during the immunosuppressant cyclosporine-A therapy led to an observable histological preservation for the renal cortex against the cyclosporine-A induced nephrotoxicity

Histological study of the effect of potassium bromate on the thyroid gland of adult male albino rats and the protective role of vitamin C supplementation

Thirty adult male albino rats were used in this study aiming to study the effect of chronic oral administration of potassium bromate on the structure of the thyroid gland and to study the possible protective role of the concomitant supplementation of vitamin C. The animals were divided equally into three groups [10 animals each]; a control group and two experimental ones. The animals of the first experimental group were subdivided equally into 2 halves. The animals of the first half were given a daily oral dose of potassium bromate 30 mg/kg body weight for successive 2 months. While the animals of the other half were given the same daily oral dose of potassium bromate for successive 6 months. The animals of the second experimental group were also subdivided equally into 2 halves. These animals were given a daily intraperitoneal injection of 20 mg/kg body weight of vitamin C for 2 and 6 months respectively simultaneous with a daily oral dose of potassium bromate as in the first experimental group. At the time of sacrifice, all the animals of each group were anaesthetized with ether inhalation and their thyroid glands were dissected out carefully and processed for light and electron microscope examinations. Light microscope observations of the thyroid glands of the potassium bromate treated rats for 2 months revealed alterations of many thyroid follicles. Their follicular cells became squamous with deeply stained nuclei. Ultrastructurally, the follicular cells contained irregular heterochromatic nuclei. Their cytoplasm contained dilated rough endoplasmic reticulum and swollen mitochondria. Mast cells were seen in the connective tissue between the affected follicles. Light microscope examination of the thyroid glands of the rats treated with potassium bromate for 6 months showed loss of the architectures of the glands. The follicular cells appeared with deeply stained nuclei and marked cytoplasmic vacuolations. Ultrastructrually, the follicular cells contained dilated and fragmented rough endoplasmic reticulum. Their nuclei showed irregular outlines and much clumps of heterochromatin. While light and electron microscope examinations of the thyroid glands of the animals treated with vitamin C concomitant with potassium bromate revealed preservation of the architectures of the glands. Most of their follicles appeared with few colloid. The follicular cells contained well developed rough endoplasmic reticulum with some dilated cisternae, numerous mitochondria with few swollen ones and cytoplasmic vacuolations. In conclusion, the results of this study revealed that chronic oral administration of potassium bromate led to structural changes in the thyroid gland which were duration dependant. Vitamin C supplementation with potassium bromate showed a moderate protection against these alterations

Histological study of the bone marrow mast cells in ovariectomized adult albino rats

Ten 90 days old female albino rats were utilized in this research aiming to study the bone marrow mast cells in ovariectomized adult albino rats in an attempt to clarify one of the possible underlying cellular causes of postmenopausal osteoporosis. These rats were equally classified into 2 groups [a control group and an experimental one]. Bilateral ovariectomy was performed to the rats of the experimental group. After 30 days of the ovariectomy, all the rats of the two groups were sacrificed. Their tibiae were dissected out carefully and their proximal parts were obtained and processed for light and electron microscope examinations. The spongy bone at the proximal tibial metaphysis of the ovariectomized rats appeared with few bone trabeculae. Numerous osteoclasts were observed in the examined sections. These cells appeared with multiple euchromatic nuclei and prominent nucleoli and their cytoplasm contained numerous mitochondria. The surrounding bone marrow contained numerous mast cells. Some of these cells were seen near the bone trabeculae. In conclusion, the concomitance between increased bone marrow mast cells number and osteoclasts number and activity with reduced bone trabeculae of the spongy bone of the proximal tibial metaphysis of the estrogen- deficient rats may suggest a role for mast cells in postmenopausal osteoporosis. So, regulation of mast cells activation may be a critical issue and a promising therapeutic approach in the treatment of this disease

Histological study on the effect of zinc deficiency on the lingual epithelium of adult male albino rats

Twelve healthy adult male albino rats weighing [200 - 300 mg] were used in this study aiming to demonstrate the possible histological alterations that may occur in the epithelium covering the lingual filiform papillae and the ventral surface of the tongue as a result of zinc deficiency. They were divided into two equal groups; a control and zinc deficient ones. Zinc deficient diet [less than 1ppm zinc] was fed to the animals of the zinc deficient group daily for 42 days. Whereas, the animals of the control group received the same diet supplemented with zinc carbonate to increase zinc concentration to 55 ppm. At the time of sacrifice, the animals of the two groups were anaesthetized by ether inhalation and their tongues were dissected out carefully and processed for light and electron microscopes examination. Light microscope examination of the dorsal surface of the tongue of zinc deficient rats revealed the presence of deformity of the filiform papillae with exfoliation of the horny layer of their covering epithelium. Also, the epithelium showed thickening of both prickle and granular layers. The cells of the later appeared large in size, irregular and lightly stained. In addition, the covering epithelium of the ventral surface appeared thick and keratinized with obliteration of the underlying connective tissue papillae. Electron microscope examination of the filiform epithelium of the same group demonstrated the cytoplasm of the basal cell layer with many vacuoles, Many irregular keratohyalin granules of different shapes and sizes were observed in the strata spinosum and granulosum, in addition to the presence of relatively thick tonofilaments. Also, partial separation of the cells of the granular layer and partial exfoliation of the covering horny layer were noticed. In conclusion, the present results showed that zinc deficiency resulted in deformity and hyperkeratosis of the filiform papillae, in addition to thickening and keratinization of the ventral surface epithelium. This alteration of the normal architecture of the lingual epithelium may be, together with the associated clinical complications, an available investigation for tissue zinc deficiency

role of antioxidant against experimentally induced diabetic peripheral neuropathy in adult male albino rats [histological and immunocytochemical study]

Fifteen healthy adult male albino rats were used in this study aiming to demonstrate the structural changes occurring in the peripheral nerves as a result of chronic diabetes and to investigate the role of vitamin E as an antioxidant. The animals were equally divided into three groups [A, B and C] [5 animals each]. Group A served as a control. Group B animals were injected intra-peritoneally with 40 mg streptozocin/kg body weight for successive 5 days. Group C animals were injected with streptozocin as those of group B then they received a daily dose of vitamin E 70 mg/kg body weight orally for successive 6 weeks. At the time of sacrifice the animals of the all groups were anaesthetized with ether inhalation and their sciatic nerves were dissected out carefully and small pieces were taken and processed for light and electron microscope examinations. Light microscope examination of the diabetic group showed the sciatic nerve was formed of numerous axons with poor myelination and with different diameters. The intensity of the reaction of the nerve growth factor [NGF] was more at the periphery than the center. Ultrastructurally, the myelin sheath showed splitting in the lamellae. The endoneurium contained mast cells and infiltrating cells in close relation with the distorted myelin. Schwann cells nuclei appeared with much heterochromatin and their cytoplasm contained few scattered segments of rough endoplasmic reticulum and poorly developed Golgi. The nodes of Ranvier exhibited irregular neurolemmal terminations. Examination of the diabetic group which received vitamin E by light microscope revealed the sciatic nerve was formed of many well myelinated axons and few ones with poor myelination. The intensity of the reaction of [NGF] was intense in the center and weak in the periphery. Ultrastructurally, Schwann cells appeared with much euchromatic nuclei and their cytoplasm contained several segments of rough endoplasmic reticulum. The related axons appeared with closely packed myelin lamellae. Vitamin E as an antioxidant exhibited a protective role against structural changes in diabetic peripheral neuropathy

Light and electron microscope study of the cardiac muscle of iron-deficient male albino rats

Twelve male albino rats [six weeks old] weighing 150-200 gm were used in this study to investigate the cardiac muscle alterations after inducing iron deficiency. The animals were divided into two equal control and experimental groups. The animals of the latter group received a diet deficient in iron, whereas, control rats were given the same diet with added ferrous sulfate. After five weeks, all the animals were anesthetized with ether and their hearts were carefully dissected and processed for light and electron microscope examination. Light microscope observations for cardiac muscle of control group showed long parallel muscle fibers with transverse striations and intercalated discs between muscle fibers. Electron microscope examination for the same group revealed cardiac muscle fibers with inter myofibrillar rows of sarcosomes. The nuclei of muscle fibers were large and oval and the myofibrils showed alternative dark and light b and s. The light b and s were traversed by dark Z-lines. Light microscope examination for cardiac muscle of iron-deficient rats showed distortion of some muscle fibers and areas of cellular infiltrations with congested blood vessels. Also, mast cells were demonstrated in the endomysium near blood vessels. Electron microscope examination for cardiac muscle of iron- deficient rats showed distorted nuclei of some muscle fibers, hypertrophy of Z-lines, narrowing of sarcomers and mitochondrial disfigurement. It was concluded that cardiac muscle of iron-deficient rats showed histological alterations, especially in the mitochondria, Z-lines and normal sarcomeric pattern of the myofibrils. So, regular check up of the hemoglobin level in the susceptible individuals for iron deficiency is recommended to avoid these changes