Assmaa O. Selim

Neuroprotective effects of placenta-derived mesenchymal stromal cells in a rat model of experimental autoimmune encephalomyelitis.

BACKGROUND Current therapies for multiple sclerosis (MS) are largely palliative, not curative. Mesenchymal stromal cells (MSCs) harbor regenerative and immunosuppressive functions, indicating a potential therapy for MS. A preparation of MSCs derived from full-term human placenta (PDMSCs) is a new approach in the treatment of patients with MS. OBJECTIVE This study aimed to rule out the possible therapy by PDMSCs in experimental autoimmune encephalomyelitis (EAE), a rat model of MS. METHODS AND RESULTS Thirty-five female Wistar rats were classified into the following groups: I, control; II, EAE untreated; III and IV, EAE treated with phosphate-buffered saline (PBS) at 9 and 16 days post-immunization (dpi), respectively; V and VI, EAE treated with PDMSCs at 9 and 16 dpi, respectively. Intravenous administration of PDMSCs at 9 or 16 dpi significantly ameliorated the disease course, decreasing brain inflammation and degenerating neurons. A reduction of axonal damage as well as an increase of oligodendrocyte precursors were recorded. Moreover, there was an engraftment of the PDMSCs into the brain tissue. Human brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF) and neurotrophin 3 (NTF3) were significantly expressed in brains of rats treated by PDMSCs. CONCLUSIONS Human PDMSCs have demonstrated striking therapeutic effects when delivered at the onset or at the peak of the disease. PDMSCs have direct neurotrophic support after their engraftment within the lesion through expression of the neurotrophins.

Effect of sodium fluoride on the thyroid gland of growing male albino rats: histological and biochemical study

Introduction Sodium fluoride (Na–F) is commonly added to drinking water and decay-preventive ingredients. Long-term exposure to Na–F leads to some adverse effects on various organs. Its structural shape is similar to iodine, with a considerable potential to cause thyroid gland dysfunction. Aim of the work The aim of the present work was to study the possible histological and biochemical changes induced by chronic Na–F exposure on the thyroid gland. Materials and methods Twenty male rats (30 days, 40–45 g) were equally divided into two groups. Group I served as a control and group II included rats that received 11 mg/kg/day Na–F orally by a gastric tube for 120 days. At the end of the experiment, rats were sacrificed after ether inhalation and blood samples were subjected to a hormonal assay of T3, T4, and thyroid-stimulating hormone (TSH) levels in addition to superoxide dismutase (SOD) and malondialdehyde (MDA). The thyroid gland tissue samples were processed for light and electron microscopic examination. Also, an immunohistochemical study was carried out for the detection of parafollicular or C cells. The results obtained were analyzed morphometrically and statistically. Results Histological examination of the thyroid follicles in the Na–F-treated rats showed different changes. Some follicles showed signs of degeneration in the form of a decrease in area % of colloid and fusion of the follicles; also, the follicular cells showed irregular dilation of rough endoplasmic reticulum, cytoplasmic vacuolation, and irregular nuclei. Other follicles showed signs of hyperactivity manifested by the presence of microfollicles, follicular epithelial cell stratification, and extensive vacuolated colloid, with an increase in the number of lysosomes. Also, hyperplasia was observed in parafollicular cells and confirmed statistically. Alterations in the thyroid structure were further confirmed by the results of the hormonal assay, which showed a significant and a highly significant decrease in serum T4 and T3, respectively, with a subsequent increase in TSH. The MDA activity increased significantly, whereas the SOD content decreased. Conclusion Our study showed that long-term low-dose exposure to Na–F affects the thyroid structure and function, leading to hypothyroidism. It can also be concluded that a mutual cooperation exists between the follicular and the C cells.

Role of hepatic stellate cells in fibrogenesis in a model of pomegranate-treated fatty liver induced by junk food in male albino rats immunohistochemical and electron microscopic study

Introduction Hepatic fibrogenesis is a common result of liver injury. It is believed to be a critical factor that leads to hepatic failure. A critical event in fibrogenesis is activation of hepatic stellate cells (HSCs). Aim of work The aim of this investigation was to study the role of HSCs in fibrogenesis in a model of pomegranate juice (PJ)-treated fatty liver induced by junk food using immunohistochemical and electron microscopic study. Materials and methods Thirty young male albino rats were divided into control (I) and experimental (II) groups. Group II was further divided into two subgroups: II-a (junk food) and II-b (pomegranate juice + junk food). After 8 weeks, blood samples were collected for detection of leptin and tumour necrosis factor alpha TNF-&agr;.Then half of the liver samples were processed for light microscopic examination, whereas the other half were prepared for electron microscopic examination. Paraffin sections were stained using H&E, glial ibrillary acid protein, &agr;-smooth muscle actin, TNF-&agr;, and transforming growth factor -beta-1 TGF-&bgr;1. Morphometric and statistical studies for assessing immunoexpression were carried out. Results HSCs markers glial fibrilar acid protein and &agr;-smooth muscle actin and cytokines TNF-&agr; and TGF-&bgr;1 in subgroup II-a showed strong positive immunoexpression. Electron microscopic study showed activated - HSCs containing granules and collagen fibrils. Proliferative and myofibroblast -HSCs were also seen in the same group. Subgroup II-b showed a nonsignificant increase in immunoexpression of HSCs markers and cytokines. However, only activated- HSCs were seen. Conclusion and recommendation Immunoexpression of HSC markers and cytokines may be used as an indicator for liver fibrosis. Presence of different types of HSCs in fatty liver explains their role in fibrosis. Further experimental and clinical studies directed toward inhibiting the activity of HSC may delay or prevent liver fibrosis occurs in many pathological conditions.

A possible correlation between the testicular structure and short photoperiod exposure in young albino rats: light and electron microscopic study

Introduction Light is considered as the first ecological factor affecting primary productivity. Several studies have attempted to relate between seasonal changed environmental light factors and the reproductive system. Aim of the work The influence of environmental light on the anatomy and physiology of different organs has been investigated intensely in a different species. Therefore, this research was designed to examine the effects of a short duration of light exposure on the histological structures of rat testes. Materials and methods Eighteen young male albino rats were divided into control (I) and experimental (II) groups. They were kept for 8 weeks in separate cages. The rats in group I were exposed daily to a normal lighting cycle of 12 h light and 12 h darkness. Light was provided by a 20-W 4-ft fluorescent lamp. Group II was exposed daily to 4 h of light and 20 h of darkness. They were housed in a small room. Its windows were covered with a black cotton material. At the end of the experiment, all rats were anaesthetized with ether, and their testes were dissected out and processed for light and electron microscopic examination. Results In group II, spermatogenic cells of some seminiferous tubules appeared separated and exfoliated. The other tubules were destroyed, with acidophilic hyaline material. Loss of germ cells was confirmed by a significantly low sperm count. Some germ cells showed a vacuolated cytoplasm and disrupted intercellular bridges with the formation of giant cells. Sertoli cells showed active phagocytic capacity with the appearance of multivesicular bodies. Hormonal assay showed a low significant testosterone level; this was supported by the presence of inactive spindle-shaped Leydig cells. Conclusions The present study confirmed that rats were structurally and functionally photosensitive. Therefore, the changes in the normal photoperiod could influence their reproductive functions.

Effect of streptozotocin-induced diabetes mellitus on the cerebellar cortex of adult male albino rats: histological and immunohistochemical study

Introduction Diabetes mellitus is a common metabolic disorder with well-known serious secondary complications. It is also associated with central nervous system damage. This damage is characterized by impairment in brain functions, with neurochemical and structural abnormalities. Aim of the work To clarify the effects of streptozotocin-induced diabetes on the histological structure of the cerebellar cortex of adult rats. Materials and methods Twenty adult male albino rats were used in this study, randomly divided into three groups. Group I was the control group; group II received a single intraperitoneal injection of 0.1 ml saline; and group III received a single intraperitoneal injection of streptozotocin at a dose of 60 mg/kg freshly dissolved in 0.1 ml saline. After 8 weeks, the cerebellum was dissected and processed for light and electron microscopic examinations and also for glial fibrillary acidic protein (GFAP) to demonstrate the astrocytes. Morphometrical and statistical analyses were carried out. Results In group III, degenerative changes were observed in neurons. Mitochondrial alterations and disarrangement of myelin sheaths with increased area of myelinated axons were observed. Dispersed presynaptic vesicles in swollen axonal terminals were also observed. However, there was good evidence of gliosis, which was supported by a significant increase in the number of GFAP astrocytes. Conclusion The cerebellar cortex was particularly susceptible to hyperglycemia-induced oxidative stress and could have contributed toward the neuronal damage and increased astrocyte activity.

Bone marrow–derived mesenchymal stem cells ameliorate parotid injury in ovariectomized rats

BACKGROUND AIMS Parotid hypofunction causes life-disrupting effects, and there are no effective medications for xerostomia. We hypothesized that mesenchymal stem cells (MSCs) have repairing effects on parotid glands of ovariectomized (OVX) rats. METHODS Forty-five adult female rats were divided into three equal groups: group I (Control group), group II (OVX-group) and group III (OVX rats that received MSCs at 4 and 8 weeks post-ovariectomy). At 12 weeks post-ovariectomy, histological (Massons trichrome and periodic acid-Schiff with alcian blue stains), immunohistochemical (caspase-3 and CD44) and morphometric studies and salivary flow rate and saliva pH determination were carried out. RESULTS Histologically, the OVX group displayed numerous irregular vacuolated acini, thickened septa with marked cellular infiltration and vascular congestion. Degenerated organelles and few or irregular secretory granules with a different density were observed. Caspase-3-positive cells were highly expressed. MSC-treated glands exhibited a considerable degree of preservation of glandular architecture with numerous CD44-expressing and few caspase-3-expressing cells. Significant decrease of the salivary flow rate in the OVX group was detected, which reverted to normal levels in group III. CONCLUSIONS MSCs ameliorated the damaging effects of ovariectomy on the parotid glands.

An experimental study of a rat model of emphysema induced by cigarette smoke exposure and the effect of Survanta therapy

The present study was performed to test the therapeutic effects of Survanta (an exogenous surfactant) on a Wistar rat model of emphysema. Thirty-five adult male Wistar rats were divided randomly into the following groups; control subgroups Ia&b (n=14); emphysematous model subgroups IIa,b&c (n=21) exposed to cigarette smoke (CS), received phosphate buffer solution (PBS) and Survanta respectively. The levels of serum myeloperoxidase (MPO), lung tissue lactate dehydrogenase (LDH), alkaline phosphatase (ALP) as well as antioxidants: catalase (CAT), superoxide dismutase (SOD) and oxidative stress: malondialdehyde (MDA) markers were measured. Immunohistochemical staining of the lung was applied with anti-P53, anti- tumor necrosis factor (TNFα) and anti-proliferating cell nuclear antigen (PCNA) to reveal the changes of the lung structure. The mean linear intercepts (MLI) of alveoli were measured to assess alveolar size. In emphysematous rats, the serum level of MPO and tissue LDH, ALP & MDA were significantly increased while; CAT and SOD were significantly decreased. Pictures analysis for all immunostains was clearly increased. In Survanta treated group, a significant improvement in all previously mentioned findings while; no improvement in alveolar diameter was detected. These results conclusively demonstrate that Survanta administration improves the inflammatory biochemical and histochemical parameters of the emphysematous lung.

Histological architecture of cardiac myofibers composing the left ventricle of murine heart

Abstract Background: Despite the fact that the exact architecture and orientation of left ventricular myocardial fibers are critical to cardiac functions either in health or disease, it is still

Harmful effects of arsenic on the cerebral cortex of adult male albino rats: light and electron microscopic studies

IntroductionArsenic is a common environmental contaminant that is available worldwide. It has been reported that human arsenic exposure causes nervous system disturbances such as polyneuropathy and neurobehavioral deficits. Aim of the workThe purpose of this work was to describe the histological changes induced by arsenic in the cerebral cortex of adult male albino rats and discuss its possible mechanisms of action. Materials and methodsTwenty adult male albino rats were equally classified into control (I) and experimental (II) groups of 10 animals each. Rats of group II were intraperitoneally injected with 2mg/kg/day of sodium arsenite for 20 days. Samples from the temporal lobes of the cerebrum were taken and processed for light and electron microscopic examination. ResultsFeatures of neurodegeneration such as shrunken, irregular, and darkly stained nuclei and degenerating organelles were observed in arsenic-treated rats. Good evidence of gliosis and disrupted blood–brain barrier were also detected. ConclusionThe adult brain is particularly susceptible to arsenic-induced oxidative stress and contributes to the neurodegenerative lesions.

Renal corpuscle alterations induced by gentamicin in adult male albino rats and a possible protective role of ginger: histological and biochemical study

Introduction Gentamicin is a widely used effective antibiotic with a possible risk of nephrotoxicity. Ginger is an antioxidant that could play a protective role in models of experimentally induced nephropathies. Aim of the work The aim of this work was to study the possible histological and biochemical changes induced by gentamicin on renal corpuscles and evaluate the possible protective effect of ginger on gentamicin-induced renal damage in adult male albino rats. Materials and methods Twenty-four adult male albino rats divided into four groups (six rats each) were used in this study. Group I served as the control group. Rats of group II received only an aqueous extract of ginger at a daily dose of 1 ml for 7 days through a gastric tube. Rats of group III were injected intraperitoneally with gentamicin sulphate at a daily dose of 80 mg/kg for 7 days. Rats of group IV were given both ginger and gentamicin at the same doses and through the same routes as the previous two groups. At the end of the experiment, the rats were sacrificed after ether inhalation and blood samples were subjected to chemical assay for assessment of blood urea nitrogen (BUN), creatinine, superoxide dismutase (SOD) and malondialdehyde (MDA) levels. Renal tissue samples were processed for light and electron microscopic examination. An immunohistochemical study was also performed for assessing &agr;-smooth muscle actin to demonstrate mesangial expansion. The obtained results were analysed morphometrically and statistically. Results Gentamicin caused several focal glomerular changes in the form of congestion and rupture of capillaries and also atrophic changes. Mesangial hyper-cellularity and increased inter-capillaries mesangial matrix were observed. Destroyed blood renal barrier was observed ultrastructurally. There was a highly significant increase in serum urea, creatinine and MDA, whereas SOD decreased. Ginger normalized the gentamicin-induced increase in serum BUN, creatinine, MDA and SOD. This was also evidenced by histological studies. Conclusion Gentamicin induced injurious effects on renal corpuscles. Coadministration of ginger during gentamicin treatment can ameliorate both the functional and histological changes induced by gentamicin.