Damage to Hepatic Thyroxine 5'-Deiodination Induced by Pathogenic Factors of Keshan Disease and the Preventive Effects of Selenium and Vitamin E

Experiments were performed to investigate the change of hepatic T4 5'-deiodination and the preventive effects of selenium (Se) and vitamin E in rats fed grains from a Keshan disease (KD) endemic area. The results showed that consumption of the endemic grain for 8 weeks caused a significant reduction in hepatic T4 5'-monodeiodinase and glutathione peroxidase activities, and a marked enhancement of hepatic malondialdehyde content. These changes could be effectively prevented through Se or vitamin E supplementation to the diet. These observations confirm the reduced ability of hepatic T4 5'-deiodination induced by the pathogenic factors existing in the endemic grains, and the preventive effects of selenium and vitamin E on the alterations. The present study suggests that the reduction in hepatic T4 deiodination in these animals may be the consequence of hepatic damage owing to uncontrolled free radical metabolism, and that the relative deficiency of vitamin E, besides selenium deficiency, may also play a role in the pathogenesis of KD.

Immunology of Kaschin-Beck Disease:Studies on lymphocyte subsets, humoral immunity and their relationship with selenium

Objective To study the humoral immunity status and distribution pattern of lymphocyte subgroups of peripheral blood mononuclear cell (PBMC) in patients with Kaschin-Beck Disease (KBD), and their relationship with erythrocyte selenium.Methods 23 X-ray diagnosed patients, 22 age- and sex- matched healthy children in KBD affected area (KAA), And 25 in KBD non-affected area (KNAA) were randomly selected. Immunohistochemistry with monoclonal antibodies anti-CD4, anti-CD8, anti-CD20 was conducted to analyze the lymphocyte subsets. Serum IgM, IgA, IgG, Complement C3 and C4 were assayed using rate nephelometry (Array 360 System, USA). The contents of erythrocyte selenium was determined by 2,3-diaminonaphthalene fluorescence assay. Results CD4+ and CD8+ cells percentage in PBMCs and serum IgA were significantly lower in KAA than those in KNAA(P<0.05). CD20+ percentage in KAA displayed a decreasing trend compared to KNAA, although not statistically significantly. No statistical differences were found in CD4/CD8 ratio, serum IgG, IgM, C3 and C4 levels. Erythrocyte selenium level in KAA still showed a pronounced decrease compared to that in KNAA. Correlation analysis showed that erythrocyte selenium contents had a strong association with the CD4 cell percentage (r=0.625,P<0.05), and also a close relationship with serum IgA (r=0.462,P<0.05). In addition, we detected a moderate correlation between the serum IgA and CD4+ percentage (r=0.130, P>0.05).Conclusion Taken together, our results suggested that children in KAA had a comparably low cellular immunity level manifested by the marked depression of CD4 and CD8 cells percentage, and their humoral immunity status was also in a state of moderate immune suppression. Of this immune disorder in KBD patients, selenium deficiency probably played a critical role via affecting the distribution pattern of peripheral blood lymphocyte. Selenium-deficiency and immune impairment maybe both have something to do with the cause-effect chain of KBD.

Vitamin E Requirement of Rats Fed on a Diet Containing Grains from the Endemic Region of Keshan Disease

Keshan disease (KD) is an endemic cardiomyopathy occurring in China. Combined selenium and vitamin E (VE) deficiency might be involved in the development of KD. It was shown in this paper that addition of 20 and 100 mg/kg DL-a-tocopherol tended to decrease malondialdehyde (MDA) content of myocardium in the rats receiving the low selenium (0.013 ppm) grains from the endemic region of KD, but not to a statistically significant extent. And addition of 200 mg/kg DL-a-tocopherol significantly decreased the myocardial MDA content, which suggested that VE requirement of the rats receiving KD endemic grains was 200 mg/kg DL-a-tocopherol. However, the MDA content in the myocardium of rats receiving KD grains added with 100 mg/kg DL-a-tocopherol was significantly decreased when selenium (0.1 ppm) was supplemented, which suggested that VE requirement of these rats was decreased to 100 mg/kg DL-a-tocopherol in the presence of selenium. The ability of VE in counteracting free radicals in myocardium of rats appeared greater than that of selenium.

Effect of Sodium Nitrite on Myocardial Glutathione Peroxidase and Protective Action of Vitamin E and Selenium

Under the condition of acute NaNO2 poisoning, the changes of myocardial GSH-Px activity of rats fed a diet composed of grains grown in the endemic region of Keshan disease and the same diet with supplementation of vitamin E or selenium were investigated. By gavage of toxic doses of NaNO2, the myocardial GSH-Px was significantly reduced (P<0.05). Vitamin E or selenium supplementation protected the enzyme activity from reducing. It is suggested that the simultaneous action of an increase in selenium and vitamin E intake and a decrease in nitrite intake might greatly prevent the occurrence of Keshan disease.