Background Adult-onset hypothyroidism has a deleterious effect on hippocampal cognitive and memory functions. This study was performed to evaluate the possible therapeutic effect of thyroxine on hippocampus degeneration in an adult male rat model of carbimazole-induced hypothyroidism and the potentiality of spontaneous recovery. Thirty-two adult male albino rats were divided equally into four groups, as follows: I (control group), II (hypothyroidism group) received carbimazole (20 mg/kg) orally once daily for 4 weeks; III (recovery group) rats were managed as in group II, then left untreated for an additional 4 weeks to assess spontaneous recovery; and IV (thyroxine-treated group): hypothyroidism was induced as in group II, then rats received levothyroxine (20 µg/kg/day) orally for 4 weeks. Rats and their corresponding controls were sacrificed after 4 weeks in group II and after 8 weeks in groups III and IV. The levels of T3, T4, and TSH were measured. Hematoxylin and Eosin staining of thyroid and hippocampal sections was performed. Additionally, toluidine blue staining and immunohistochemical staining for PCNA, GFAP, and synaptophysin were applied to hippocampus sections. Both morphometric measurements and statistical analysis were performed. Results Comparison of thyroxine-treated group with hypothyroidism and recovery groups revealed a significant reduction in TSH  level and an increase in T3 and T4 levels, as well as improved histological architecture in both the thyroid and hippocampal sections. Hippocampal sections revealed a significant decrease in the mean area percent of GFAP, a significant increase in the mean number of PCNA-positive cells in the subgranular zone (SGZ); a niche for the adult neural stem cells (NSCs) in the hippocampus; and a significant increase in the mean area percent as well as the mean optical density of synaptophysin. Conclusion Hippocampal degeneration is induced by hypothyroidism and can be restored by thyroxine replacement therapy, probably through neuronal cell preservation, synaptogenesis, and stimulation of neurogenesis in SGZ. On the other hand, spontaneous recovery from this degeneration was inadequate.

The possible protective effect of Losartan, an angiotensin II receptor 1 antagonist, on bleomycininduced rat lung fibrosis was evaluated using histological and immunohistochemical techniques. Twenty adult male albino rats were divided into 4 groups each of five rats: Group I (control) given saline both I.V and orally, Group II given bleomycin 10mg/Kg/day I.V., Group III given losartan 10 mg/Kg/day orally and Group IV given both bleomycin and losartan. Lung sections were taken at the 28 th day of the experiment, stained with H&E, Masson's trichrome, Orcein and immunohistochemical stain for α-SMA. This was followed by morphometric measurements and statistical analysis. The present study showed that bleomycin induced fibrotic changes in the lung in the form of thickened interalveolar septa filled with proliferated type II pneumocytes, fibroblasts and inflammatory cells with significant increase in collagen and elastic fibres deposition and in α-SMA immunoreactivity. It was found that concomitant treatment with losartan (Group IV) showed significant reduction in these fibrotic changes. The changes in α-SMA immunoreactivity in different groups showed the same pattern as those of collagen and elastic fibres. Thus, it could be concluded that myofibroblasts might play a pivotal role in induction of lung fibrosis and they could be a target of future therapeutic strategies.

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Introduction: Chemotherapy may result in temporary or permanent gonadal toxicity in male patients. Loss of fertility potential can be devastating to patients, especially, during the child-bearing period. Aim of Work:The present study was planned to investigate the possible protective effect of melatonin, in a rat model of cisplatin-induced testicular toxicity. Materials and Methods: Forty five adult male albino rats (180-200 grams each) were divided into four groups; Group I Control (n=15) received 0.9% sodium chloride and/or distilled water as a vehicle. Group II (n=10) were injected intraperitoneally (I.P.) with a single dose 7 mg/kg of cisplatin& were sacrificed after 10 days. Group III (n=10) received melatonin daily orally at a dose of 8 mg/kg/day for 10 days. Group IV (n=10); oral melatonin administration started 5 days before the single I.P. injection of cisplatin, followed by continuation of melatonin for further 10 days. Testicular sections were subjected to H&E, immunohistochemical staining for anti-inducible nitric oxide synthase (iNOS) and anti-androgen receptor (AR). Results: The study proved the protective effect of melatonin against testicular toxicity, when administered prior to and concomitant with cisplatin therapy; confirming the anti-oxidant potential of melatonin. Conclusion: Our findings provide experimental evidence ensuring the protective effect of melatonin, when administered prior to, and concomitant with the chemotherapeutic agent cisplatin. Meanwhile, melatonin administered alone seemed to induce injury to the testis.

Background: Chemical peels represent useful tool for improving skin texture and the effects of ageing. With the advent of newer chemical peels, there is now a wide range of peeling agents that can be applied on specific patients. Aim of the work: The present work was designed to evaluate and compare histologically between two of the most commonly used peeling agents in medium depth chemical peel: TCA (35%) and GA (70 %). Materials and Methods: This study was carried out on forty adult male albino rats. They were divided into five groups, eight rats each. Group І: Control rats that received no peeling session. Groups П and ПI: Received a peel session of TCA 35% and skin specimens were taken after one week and three weeks respectively. Groups IV and Group V: Received a peel session of glycolic acid 70% and skin specimens were taken after one week and three weeks respectively. Sections were prepared to be stained by H&E, Masson's trichrome, Orcein and immunohistochemichal staining for CD34, which is a marker for stem cells in hair follicle bulge region. Morphometric measurements of epidermal thickness, dermal thickness, area percent of collagen and elastic fibers, area percent and optical density of immunopositive cells for CD34 were done by image analyzer. Data obtained were statistically analyzed. Results: The present study revealed that after one week of medium depth chemical peel (by TCA (35%) or GA (70 %), the skin showed increase in epidermal and dermal thickness, increase in elastic and collagen fibers which became more organized and regularly arranged. It also showed pronounced increase in CD34 immunopositive cells (hair bulge stem cells, spindle cells of the reticular dermis, endothelial cells of dermal vessels and sebaceous glands). Three weeks after the chemical peel, the skin showed further significant increase in epidermal thickness, dermal thickness, collagen and elastic fibers. However, there was marked decrease in area percent and optical density of CD34 immunopositive cells. Conclusion: The present study revealed that both TCA (35%) and GA (70%) are effective in stimulation bulge stem cells and in improving the skin morphology with no significant difference between the two reagents.