Histological and immunohistochemical study of the effect of experimentally induced hypothyroidism on the thyroid gland and bone of male albino rats

Hyperstimulation of follicular cells using a goitrogen [propylthiouracil [PTU]] caused thyroid dysfunctions that were associated with disturbances in adult bone turnover. This work was carried out to study the probable relationship between follicular and parafollicular cells in drug-induced hypothyroidism caused by PTU and consequently its effect on bone. The present work was carried out on 30 adult male albino rats divided into three groups. Group I was the control group; group II [the hypothyroid group] rats received PTU orally at a daily dose of 16.875 mg/rat of an average weight of 180 g for 4 weeks; group III was the recovery group. Thyroid glands were examined using histological and immunohistochemical techniques for calcitonin Ab-2. The midshaft of the femur bones of the studied groups was prepared and stained with H and E. In hypothyroid rats both follicular and C cells displayed signs of hyperactivity as the mean follicular cell height was significantly increased [P<0.05] compared with the control group. Moreover, the calcitonin immunoreactive cells showed a significant increase [P<0.05] in the mean values of their height and mean area% and number compared with the control group. These findings were reflected on bone sections in terms of a significant increase [P<0.05] in cortical bone thickness and a significant narrowing [P<0.05] of the Haversian canals when compared with the control group. It could be concluded that C cells are not exclusively involved in calcium regulation independent of follicular cell activity; however, these cells interact with the surrounding follicular cells, enabling more effective coordinated functions between the two endocrine populations. Moreover, experimentally induced hypothyroidism resulted in increased C-cell number, consequently decreasing bone resorption and increasing cortical bone thickness

Can human cord blood-derived stem cells improve statin-induced myopathy in rats? A histological and immunohistochemical study

Primary myopathies of skeletal muscle are diseases with worldwide prevalence for which effective treatment is urgently needed. The aim of this study was to investigate the ability of human umbilical cord blood [HUCB] stem cells to repair damaged skeletal muscle in a rat model of statin-induced myopathy. This study included 24 adult male albino rats divided equally into four groups: the control group; the myopathy group in which myopathy was induced by administration of simvastatin [80 mg/kg/day orally for 6 weeks]; the stem cell-treated myopathy group in which myopathy was induced by administration of simvastatin with subsequent local injection of 1×10[6] HUCB stem cells in the right gastrocnemius; and the untreated myopathy group in which myopathy was induced by administration of simvastatin and then left without treatment for 2 weeks. Specimens of the right gastrocnemius from all rats were prepared, sectioned, and subjected to H and E, Prussian blue, and Masson's trichrome stains in addition to immunohistochemical staining for alpha smooth muscle actin to reveal myofibroblasts. The area% of collagen and muscle fibers and the number of myofibroblasts/high-power field were ascertained. All measurements were statistically analyzed. The gastrocnemius of the myopathy group showed frequent necrotic and damaged muscle fibers, which were replaced by fibrous and fatty tissues. Compared with control rats, there was significant decrease in the area% of muscle fibers and significant increase in the area% of collagen and in the number of myofibroblasts. Two weeks later, there was partial repair of the muscle with no significant differences between stem cell-treated and untreated myopathy groups, which reflects the failure of stem cells to repair damaged myofibers. HUCB stem cells have poor therapeutic effect for myopathy and might be hindered by the complex environment of a severely inflamed and degenerated muscle

histological study on the effect of experimentally induced hyperthyroidism on adult albino rat testis

The thyroid hormone is a regulator of growth, development and metabolism in all tissues, and an altered thyroid status affects many organs. Studies correlating male sexual function with thyroid disorders are limited, probably because thyroid disorders are limited in men. The present work aimed to throw light on the effect of experimentally induced hyperthyroidism on the testes of adult albino rats with respect to testicular morphology, androgen receptor [AR], proliferating cell nuclear antigen [PCNA] and connexin43 [CX43] protein. Eighteen adult albino rats were used in this study and were divided into three groups of six rats each. Group I received 0.5 ml saline solution by intraperitoneal injection once daily for 4 weeks. Group II received an intraperitoneal injection of 40microg/kg L-thyroxin dissolved in saline solution daily for 4 weeks. Group III received thyroxin as in group II and were sacrificed 1 month after cessation of drug administration. Before scarification, serum thyroxin [T4] levels were determined. Sections were subjected to H and E and immunohistochemical staining for anti-AR, anti-PCNA and anti-connexin 43 antibodies. Morphometric studies included determination of the area% of immune reactions. In group II, the seminiferous tubules were lined by scanty apoptotic cells. There was homogeneous material between the seminiferous tubules. There was a significant decrease in the mean area% of anti-androgen, anti-PCNA and anti-CX43 antibodies compared with the control group. In group III the seminiferous tubules were apparently normal in shape and contained sperm in their lumen, separated by interstitial tissue. Although the mean area% of anti-AR, anti-PCNA and anti-CX43 was still lower, only the anti-PCNA antibody showed significant difference when compared with the control group. The current study showed that hyperthyroidism induced pronounced morphological changes in the testis