278-281The 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-α and IFN-γ levels. Rats
exposed to propoxur for 4 weeks showed significant decrease in
DTH, LMI and MMI responses. Propoxur also suppressed TNF-α
and IFN-γ 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