ABSTRACT
The effect of melatonin, a major secretory product of the pineal gland, in attenuation of propoxur (2-isopropoxy phenyl N-methyl carbamate)-induced modulation of cell-mediated immune (CMI) response was studied in rats. Male Wistar albino rats were exposed to propoxur (a widely used pesticide) orally (10 mg/kg) and/or melatonin (10 mg/kg) orally for 4 weeks. CMI was measured by delayed-type hypersensitivity (DTH), leucocyte and macrophage migration inhibition (LMI and MMI) responses and estimation of cytokines TNF-alpha and IFN-gamma levels. Rats exposed to propoxur for 4 weeks showed significant decrease in DTH, LMI and MMI responses. Propoxur also suppressed TNF-alpha and IFN-gamma production significantly. Administration of melatonin alone caused a significant increase in DTH response. Although there were no changes in the LMI and MMI response, the cytokine levels were significantly increased, as compared to control. Co-administration of melatonin along with propoxur significantly nullified the effect of the pesticide on the CMI response, except DTH and reversed levels of cytokines to near control/normal values. Thus, melatonin treatment considerably attenuated immunomodulation caused by sub-chronic treatment of propoxur in experimental animals.
Subject(s)
Administration, Oral , Animals , Antioxidants/administration & dosage , Cytokines/immunology , Hypersensitivity, Delayed/immunology , Immunity, Cellular/drug effects , Leukocytes/drug effects , Macrophages/drug effects , Male , Melatonin/administration & dosage , Pesticides/antagonists & inhibitors , Pineal Gland/chemistry , Propoxur/antagonists & inhibitors , Rats , Rats, Wistar , Time Factors , Tumor Necrosis Factor-alpha/immunologyABSTRACT
In the present work, fifty adult male albino rats were divided into five groups, 10 animals each. Group I was kept as control. Group II, III and IV were subjected to a daily intraperitoneal injection for 21 days with [1,2 and 3 ml] of peptide pineal extract of camel [melatonin-free extract] respectively, group V was injected intraperitoneally with with 50 ug melatonin for the same period. A significant decrease in serum levels of thyroxine [T4], triiodothyronine [T3] cholesterol and hepatic cholesterol were produced from injection of peptide pineal extract and melatonin. A non significant decrease in serum triglycerides was obtained after treatment. In the present work, the suppressive effect of melatonin free pineal extract of camel on the serum levels of T4, T3, cholesterol, triglycerides and hepatic cholesterol was dose dependent. The suppressive effect of pineal extract and melatonin on serum levels of T4 and T3 may be due to suppression of TRH release, TSH regulation at level of pituitary and also may be due to suppression of thyroid secretion directly and/or acceleration of thyroid hormone disposal. The depressive effect of pineal extract and melatonin on serum levels of cholesterol, triglycerides and hepatic cholesterol may be due to increased rate of hepatic synthesis, destruction and intestinal excretion of cholesterol, or may be due to increased lipoprotein lipase activity. The present study suggest that, changes in lipids are not secondary to changes in thyroid hormones, but may reflect separate mechanism over cholesterol and triglyceride metabolism exerted by melatonin-free pineal extract and melatonin
Subject(s)
Pineal Gland/chemistry , Thyroid Hormones/metabolism , Cholesterol/analysis , Rats , Thyroxine , Triiodothyronine , TriglyceridesABSTRACT
La glándula Pineal es un transductor neuroendocrino que forma parte de la sincronización de múltiples ritmos biológicos endocrinos a través de mecanismos aún no bien comprendidos y sobre los que influyen factores como el estímulo lumínico y la relación luz-oscuridad. Sus factores biologicamente activos corresponden a tres familias hormonales: los indoles, los péptidos de bajo peso molecular y las proteínas. En este artículo se presenta de manera general los conceptos conocidos sobre la glándula Pineal(AU)/