Journal of Pharmacy Research Vol.8 Issue 3.March 2014 Debosree Ghosh et al. / Journal of Pharmacy Research 2014,8(3),336-342 336-342 Research Article ISSN: 0974-6943 Available online through www.jpronline.info * Corresponding author. Dr. Debasish Bandyopadhyay Oxidative Stress and Free Radical Biology Laboratory, Department of Physiology, University of Calcutta University College of Science and Technology 92, APC Road, Kolkata 700 009 India INTRODUCTION Lead is an environmental pollutant, widely distributed, naturally oc- curring, toxic heavy metal. 1 Lead is also recognized as an occupa- tional hazardous metal 2 which if enters the body accumulates in soft organs and cannot be metabolized by the body. 3 Lead is one of the few natural substances that have no known use in the human body. 4 At even very low level, lead has been shown to cause health prob- lems. 4 The difficulty with lead is that once it is mined from the earth, there is no known way to destroy or make it harmless. Lead reduces the amino levulinic acid synthesis by down-regulating the gene ex- pressing amino levulinic acid synthase and thus lead leads to impair- ment of erythropoiesis. 3 Heavy metals like lead, cadmium etc. have very long half life and are severely toxic at a very low dose 2 . Studies revealed the involvement of oxidative stress as an important mechanism for heavy metal toxicity 5 .The toxicity of lead (Pb) is well documented and involve- Melatonin protects against lead acetate-induced changes in blood corpuscles and lipid profile of male Wistar rats Debosree Ghosh 1 , Monalisa Dey 1 , Arnab Kumar Ghosh 1 , Aindrila Chattopadhyay 2 and Debasish Bandyopadhyay 1*# 1 Department of Physiology, Oxidative Stress and Free Radical Biology Laboratory, University of Calcutta, University College of Science and Technology, 92, APC Road, Kolkata 700 009 India. #Principal Investigator, Centre with Potential for Excellence in a Particular Area (CPEPA), University of Calcutta, University College of Science and Technology, 92 APC Road, Kolkata 700 009 India. 2 Department of Physiology, Vidyasagar College, 39, Shankar Ghosh Lane,Kolkata 700006, India. Received on:21-02-2014; Revised on:01-03-2014; Accepted on:07-03-2014 ABSTRACT Treatment of rats with lead acetate at a dose of 15 mg / kg body weight intraperitoneally (i.p) for a period of seven consecutive days caused alterations in the total count of erythrocyte, total count of leukocyte, hemoglobin content, mean corpuscular hemoglobin content, neutrophil count, small lymphocyte count, eosinophil count, erythrocyte sedimentation rate (ESR), total cholesterol, triglyceride, HDL cholesterol, LDL cholesterol, Total cholesterol: HDL cholesterol, LDL cholesterol :HDL cholesterol. All these changes were ameliorated when the rats were pre- treated with melatonin at a dose of 10 mg / kg (fed orally) for a similar period of time. The results of the current studies indicate melatonin’s ability to mitigate heavy metal-induced alterations in blood tissue. This is probably brought about through the antioxidant activity of melatonin and may have future therapeutic relevance in humans exposed to lead environmentally or occupationally and in situations where chelation therapy has limited success. Key words: Melatonin, blood, antioxidant, lead acetate, LDL, HDL, Cholesterol, ESR ment of oxidative stress in lead toxicity is also recognized. 3, 6, 7 Effect of lead exposure in experimental animals and human has been studied in considerable detail. 8 Melatonin (N-acetyl-5-methoxytryptamine) was discovered as a po- tent antioxidant in 1993. 9 Melatonin’s ability to protect cells and or- gans from oxidative/nitrosative damage has been confirmed in more than a thousand publications. 10 The indoleamine, melatonin, is pro- duced in all animals and also in plants. 11 The antioxidative properties of melatonin are well known. Studies reveal protective action of mela- tonin against heavy metal induced toxicity and tissue damages. 6, 12, 13 Ameliorative actions of melatonin against a variety of situations in- volving oxidative stresses are currently intensely being investigated. 14 We have studied the protective effect of melatonin against lead acetate-induced oxidative damage in liver, heart and kidney tissues of male Wistar rats. 6, 13 Studies also reveal protective action of melatonin in situations of lead induced hematotoxicities. 15 Melatonin has also been shown to en- hance the antioxidant capacity of blood. 16 Melatonin has many functions in organisms, i.e., helping to synchro- nize circadian rhythms 17 , sleep promotion 18 , immune stimulation 19 , seasonal reproductive regulation 21 , oncostatic 21 , antidepressive 22