Lithium is a toxic alkaline metal that occur in the environment as industrial pollution and therapeutic use.
Lithium is widely used in medicine in the treatment of mania and mood disordered, however its administration causes
many side effects. The present study aimed to evaluate the protective effect of melatonin and thymoquinone as antioxidants
against lithium toxicity. The study is designed five groups of male albino rats (6 for each group): I (Control)- treated with
drinking water and food, II (Li)-treated with lithium chloride (LiCl), III-treated with LiCl and melatonin, IV-treated with
LiCl and thymoquinone, and V-treated with LiCl combined with melatonin and thymoquinone. The following parameters
were determined: red blood cells, hemoglobin, haematocrit, mean corpuscular volume, mean corpuscular heamoglobin
concentration, platelets, white blood cells, neutrophils, eosinophils, basophiles, monocytes and lymphocytes. Also,
biochemical analysis such as glucose, total proteins, albumin and activities of alkaline phosphatase, aspartate
aminotransferase and alanine aminotransferase in plasma as well as urea, uric acid, creatinine, cholesterol and triglycerides
were determined. Results showed that oral administration of lithium chloride caused a non-significant decrease in RBCs ,
whereas it caused a significant decrease in hemoglobin (Hb) concentration, haematocrit(Ht), mean corpuscular
volume(MCV), mean corpuscular hemoglobin concentration(MCH), eosinophils ,monocytes and lymphocytes,
respectively. But, it caused a significant increase in the WBCs , the platelets and neutrophils, relative to the control group.
Lithium significantly decreased serum glucose, total protein, albumin, whereas it significantly increased activities of
alkaline phosphatase, aspartate aminotransferase and alanine aminotransferase, respectively, relative to the control. On the
other hand, it caused a significant increase in the plasma levels of urea, uric acid, creatinine, cholesterol and triglycerides,
respectively, relative to that of control.
Administration of lithium chloride combined with either melatonin or thymoquinone, or both of them removed the toxic
effects of lithium chloride on the above parameters via decreasing and increasing their values. These findings demonstrate
that melatonin and thymoquinone may attenuate the toxic effects of lithium on the blood parameters, hepatic and renal
functions in the experimental animals.