Wafaa Ibrahim

Monoamine concentrations changes in the PTU-induced hypothyroid rat brain and the ameliorating role of folic acid

Thyroid hormones are recognized as the key metabolic hormones that play a critical role in the development of central nervous system (CNS) throughout life. The present study was designed to determine the changes in brain monoamine concentrations in 6-n-propyl thiouracil (PTU)-induced hypothyroid rats, in addition to the ameliorating role of folic acid treatment. Fifty male albino rats were equally divided into five groups; first and second groups were the control and folic acid groups, respectively, while the third group was the hypothyroid group in which the rats received PTU in drinking water for 6 weeks. The fourth and fifth groups were co- and post-treated folic acid groups with hypothyroid rats, respectively. Our results revealed that serotonin and norepinephrine concentrations were significantly decreased in the hypothalamus and cortex, while it significantly increased in the hippocampus of hypothyroid rats when compared with control group. Serotonin and norepinephrine concentrations were decreased in hypothalamus and cortex in co- and post-treated folic acid groups with hypothyroid rats, while the concentration of dopamine were significantly increased in the hypothalamus and hippocampus of the hypothyroid rats and co-treated folic acid group with hypothyroid rats. In cortex, the dopamine concentration was significantly increased in hypothyroid rats and post-treated folic acid group with hypothyroid rats, while it significantly decreased in co-treated folic acid group with hypothyroid rats when compared with the control group. Also, our results revealed that, folic acid treatment was better if it is administered as an adjuvant after returning to the euthyroid state by withdrawing PTU from the drinking water.

Proliferating Cell Nuclear Antigen as a Molecular Biomarker for Spermatogenesis in PTU-Induced Hypothyroidism of Rats

The thyroid hormone has few serious effects on the testes except during the neonatal stage. There is little knowledge concerning the prolonged effect of thyroid hormone deficiency throughout the rat’s life span and its effect on spermatogenesis. Proliferating cell nuclear antigen (PCNA) is a nuclear matrix protein, which is essential for multiple cell cycle pathways. Here we used PCNA immunohistochemistry as a marker to differentiate between the testes of control and hypothyroid rats. About 20 rats were equally divided into 2 groups; the first group was the control group, while the second group was the experimental group in which rats were fed 0.05% 6-n-propyl thiouracil (PTU) in drinking water for 6 weeks. Immunohistochemistry, using an antibody against PCNA, showed at least 3 differences in the pattern of PCNA immunoreactivity (PCNA-ir). First, PCNA-ir was not detected in Sertoli and Leydig cells in the testes of control rats and detected in some of the hypothyroid rats. Second, in the control group more than 96% of spermatogonia were PCNA-positive cells; however, hypothyroidism caused the reduction to approximately 25% PCNA staining in spermatogonia. The third difference was in the abnormal distribution of spermatogonia seen in the hypothyroid rat testis, not in the control one. These results suggest that prepubertal hypothyroidism affects the proliferation of spermatogenic cells leading to impaired spermatogenesis and that PCNA index is a useful marker for assessing germ cell kinetics and spermatogenesis in prepubertal hypothyroidism.

The effect of folic acid as an antioxidant on the hypothalamic monoamines in experimentally induced hypothyroid rat

Thyroid hormones are recognized as key metabolic hormones that play a critical role in the central nervous system development throughout life. In the present study, we studied the biochemical changes of hypothalamus of hypothyroid rats at post-pubertal stage, and the possible ameliorating effect of folic acid. A total of 50 male albino rats were equally divided into five groups; the first and second groups were the control and folic acid groups, respectively, while the third group was the hypothyroid group in which rats received daily 6-n-propyl-2-thiouracil (PTU) in drinking water for 6 weeks to induce hypothyroidism. The fourth and fifth groups were hypothyroid rats treated with folic acid for 4 weeks during and after receiving PTU, respectively, and were dissected after 6 and 10 weeks, respectively. There was a significant increase in plasma total homocysteine, malondialdehyde (MDA), oxidized glutathione\reduced glutathione and total nitric oxide and hypothalamic MDA, serotonin and norepinephrine in the hypothyroid rats group as compared to the control group. This reflects hyperhomocysteinaemia and oxidative stress associated with hypothyroid state. On the other hand, hypothalamic total nitric oxide and dopamine in the hypothyroid rats group were significantly decreased when compared to the control group. Treatment of hypothyroid rats with folic acid improves the oxidative stress and hypothalamic monoamines. Our results revealed that, folic acid treatment was better if it is administered as an adjuvant after returning to the euthyroid state.

Folic acid alleviates oxidative stress and hyperhomocysteinemia involved in testicular dysfunction of hypothyroid rats.

Although there is general agreement that thyroid hormone is an important hormonal regulator of testis physiology during development period, its role in the post-pubertal and adult testes is still controversial. Furthermore, most experimental studies to date have focused on thyroid hormone effects on the developing testes and only limited data are available on its role in spermatogenesis. This study evaluated some biochemical alterations in post-pubertal hypothyroidism and its impact on testicular function. Additionally, the ameliorating role of folic acid supplementation was investigated. Fifty male albino rats were randomly divided into five groups (group I, control; group II, folic acid; group III, 0.05% propylthiouracil-induced hypothyroid rats; group IV, co-treatment; group V, post-treatment). Plasma total homocysteine, total NO metabolites, malondialdehyde and GSSG/GSH ratio quantified by HPLC significantly (P<0.05) increased in hypothyroid rats as compared to controls. These biochemical alterations at least in part disrupted spermatogenesis in these experimental models. Folic acid supplemented after restoration of the euthyroid state (group V) presented better amelioration to spermatogenesis over its concurrent supplementation (group IV). This postulates an indirect negative impact of post-pubertal hypothyroidism on testicular function through development of these alterations. This is plus the observed role of folic acid supplementation in enhancing spermatogenesis, boosting sperm concentration and building up the antioxidant status against the oxidants in the present study. If confirmed in human beings, our results could propose that folic acid can be used as an adjuvant therapy in hypothyroidism disorders with thyroxin replacement therapy.

Treatment with folic acid ameliorated the histopathological alterations caused by propylthiouracil-induced hypothyroid rat testes

Hypothyroidism is an underactive thyroid gland that cannot make enough thyroid hormone to keep the body running normally. Here we studied the histopathological, immunohistochemical, and ultrastructural changes in the hypothyroid rat testes at the postpubertal stage, in addition to the ameliorating role of folic acid in enhancing spermatogenesis, boosting sperm concentration and building up the antioxidant status against the oxidants. A total of 50 male albino rats were equally divided into 5 groups; the first and second groups comprised the control and folic acid groups, respectively; while the third group comprised the hypothyroid group in which rats received 6-n-propyl-2-thiouracil in drinking water for 6 weeks to induce hypothyroidism. The fourth and fifth groups comprised hypothyroid rats treated with folic acid for 4 weeks and dissected after 6 and 10 weeks, respectively. Testes in the hypothyroid rats showed marked morphological and histological changes in the seminiferous tubules with a reduction in sperm count. Our results indicate that hypothyroidism adversely affects spermatogenesis, suggesting that thyroid hormone might play an important role not only in controlling normal testicular development but also in maintaining normal testicular function and spermatogenesis. Further, we suggested an ameliorating role of folic acid in the relief of testicular tissue from changes due to hypothyroidism. However, we found that the best results were found in cases where folic acid was used as an adjuvant therapy for returning to the euthyroid state.

Trehalose enhances the antitumor potential of methotrexate against mice bearing Ehrlich ascites carcinoma

Methotrexate (MTX) is commonly used as a standard chemotherapy for many cancers, however its usage required high doses thereby leading to severe adverse effects. In a trial to find a suitable neoadjuvant therapy to decrease MTX dosage without lowering its chemotherapeutic efficacy, we investigated the antitumor effect of trehalose (TRE) on mice bearing Ehrlich ascites carcinoma (EAC) and checked whether TRE can enhance the antitumor potential of MTX. Treatment with TRE induced anti-tumor effects against EAC as reveled by a remarkable decrease in body weight, tumor volume, count of viable tumor cells, expression of the anti-apoptotic gene Bcl2 as well as by a significant increase in mean survival time, life span and expression of the apoptotic gene caspase-3. TRE also caused a significant decrease in autophagic activity of EAC cells as evident by reduction in the expression of the autophagic gene Beclin 1 (Bec1) and the fluorescence intensity of autophagosome marker. Additionally, TRE restored the altered hematological and biochemical parameters and improved the disrupted hepatic tissues of EAC-bearing mice. Interestingly, co-administration of TRE and MTX showed highest anti-tumor effect against EAC. These data indicate that TRE enhances the antitumor potential of MTX and could be used as neoadjuvant drug to increase the efficacy of the antitumor drug, MTX.

Biochemical and histopathological studies of the PTU-induced hypothyroid rat kidney with reference to the ameliorating role of folic acid

Thyroid hormones (THs) are essential for growth and development of the kidney. Also TH influences glomerular filtration and tubular functions. Hypothyroidism negative influences kidney function indirectly by affecting the cardiovascular system and the renal blood flow, and directly by affecting glomerular filtration, tubular functions and the structure of the kidney. The purpose of this study was to evaluate changes in biochemical markers, oxidative stress parameter and histological changes in kidney of hypothyroid rats before and after treatment with folic acid. Hypothyroidism was induced for 6 weeks by the administration of propylthiouracil in drinking water. Urea and creatinine were measured to evaluate the changes in kidney function. Also malondialdehyde, nitrite, nitrate and other oxidative stress parameter were measured in serum and kidney tissue as indicators of oxidative damage. Kidney function and oxidative stress parameters in hypothyroid rats were significantly changed compared to those in control rats. Treatment with folic acid helps in improving the adverse effect of hypothyroidism; the histological study also confirms this finding.

Light and ultrastructural study in the propylthiouracil-induced hypothyroid rat heart ventricles and the ameliorating role of folic acid

Thyroid hormones have marked effects on the growth, development, and metabolic function of virtually all organs and tissues. Thyroid status is an important determinant of cardiovascular function. The present work studied the histopathological and ultrastructural changes in the hypothyroid rat left ventricle at post-pubertal stage, in addition to the ameliorating role of folic acid. A total of 50 male albino rats were randomly divided into 5 groups (group I, control; group II, folic acid; group III, propylthiouracil-induced hypothyroid rats; group IV, co-treatment with folic acid; group V, post-treatment). In order to ensure the hypothyroid state, the level of serum triiodothyronine (T3) and thyroid stimulating hormone (TSH) through the dose period was regularly determined. The TSH levels were significantly higher while T3 levels were significantly lower in hypothyroid rats when compared to control group. The high-performance liquid chromatography analysis showed an increase in homocysteine (Hcy) in the hypothyroid rats group when compared to the control group. The histopathological studies of the ventricle in hypothyroid rats revealed hydrophobic changes in myofibrillar structure with striations, myocardial atrophy, nuclear pyknosis, cytoplasmic vacuoles, and cytoplasmic eosinophilia. Transmission electron micrographs in the myocardium of hypothyroid rats revealed a marked reduction in muscle fibre mass, a marked degeneration of muscle fibres, swollen mitochondria, dilated sarcoplasmic reticulum and more prominent perinuclear oedema observed in the cardiac myocytes. In co-treated hypothyroid rats with folic acid, a regular arrangement of muscle fibres, mild swelling of myofibrillar structure with striations and no continuity with adjacent myofibrils were observed while the post-treated hypothyroid rat with folic acid showed normal architecture of myofibrillar structure with striations and continuity with adjacent myofibrils. In conclusion, our results indicated that folic acid had ameliorative effect against cardiac damage induced by 6-n-propyl-2-thiouracil and the best results were found in case of using the folic acid as an adjuvant therapy after returning to the euthyroid state.

Effect of histidine on autotaxin activity in experimentally induced liver fibrosis

The aim of this study was to explain whether serum autotaxin (ATX) activity might be a target for regulation of liver fibrosis and to evaluate the hepatoprotective and antifibrotic effects of histidine in thioacetamide (TAA)–induced liver fibrosis in rats. This study was carried out on 100 Wistar Albino rats, classified into five groups, each containing 20 rats: Group I (control group), Group II: rats were given histidine intraperitoneally, Group III: rats were injected intraperitoneally with TAA, Group IV: rats were injected with L‐histidine together with TAA, and Group V: rats were injected with TAA for 1 month then treated with intraperitoneal injection of L‐histidine for another month. At the end of experiment, blood and liver were collected for determination of some liver enzymes, plasma total antioxidant capacity (TAC), serum ATX activity, and liver tissue hydroxyproline. Thioacetamide treatment caused significant increases in liver enzymes, ATX activities, and liver hydroxyproline, but a significant decrease in plasmas TAC. Upon treatment with histidine, a significant decrease in liver enzymes, ATX activities, and liver hydroxyproline was observed with a significant increase in plasma TAC in Group IV and a significant decrease in Group V. Histidine as an antioxidant has a protective effect on TAA‐induced liver fibrosis; it is beneficial in rats not only by inhibition of collagen synthesis and increasing TAC but also by inhibition of ATX activities thus reducing its capacity to produce lysophosphatidic acid, which has a role in liver fibrosis.

Histopathological and immunohistochemical alterations in rat heart after thyroidectomy and the role of hemin and ketoconazole in treatment.

The heart is a major target organ for thyroid hormone action and marked changes occur in cardiac function in the case of hypo- or hyperthyroidism. Also, thyroid hormone has a significant regulatory effect on the rate of heme oxidation in the liver. Heme oxygenase (HO) is a heme-catabolizing enzyme that converts heme into biliverdin, iron and carbon monoxide. HO(-1) and its reaction products protect the heart and vasculature in pathological conditions. We studied the changes in the heart structure of thyroidectomized rat at the post-pubertal stage, in addition to the role of hemin as HO inducer and ketoconazole (KTZ) as HO inhibitor in treatment. 35 male Wistar rats were equally divided into seven groups; the first and second groups were the control and Sham-operated groups respectively while the 3rd and 4th groups were subjected to sham operation then treated with hemin (G(3)) and KTZ (G(4)). The 5th group (G(5)) was thyroidectomized group. The 6th and 7th groups were subjected to thyroidectomy then treated with hemin (G(5)) and KTZ (G(6)) respectively. Serum T(3) & TSH levels in thyroidectomized rats were significantly decreased and increased respectively when compared with the control group. Left ventricle section in the heart of thyroidectomized rats showed many of abnormalities as hydrophobic changes of myofibrillar structure with striations, myocardial atrophy and edema, focal haemorrhage when compared with that in control and sham groups. The iNOS label index was significantly decreased in thyroidectomized rat heart (grade 1) and their levels were significantly increased in treated thyroidectomized rats with hemin and KTZ (grades 3 & 2 respectively) when compared with control and sham rat groups (grade 4). Treatment of thyroidectomized rat with hemin improves the histopathological alternation and the intensity of iNOS immunoreactive cells demonstrating the recovery of some injury.