Tehran University of Medical Sciences Journal of Arthropod-Borne Diseases 2322-1984 10 2 2016 05 05 159 167 EN Mehri Ghafourian Health Research Institute, Research Center of Thalassemia and Hemoglobinopathy, Department of Immunology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Neda Ganjalikhanhakemi Department of Pharmacology, School of Pharmacy, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Ali Asghar Hemmati Department of Pharmacology and Toxicology, School of Pharmacy, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Rouhullah Dehghani Department of Environmental Health, School of Health and Social Determinants of Health (SDH), Research Center, Kashan University of Medical Sciences, Kashan, Iran Wesam Kooti Student Research Committee, Kurdistan University of Medical Sciences, Sanandaj, Iran 2015 10 13 2015 10 13 Background: The aim of this study was to investigate the effect of Hemiscorpius lepturus venom on leukocytes and the leukocyte subgroups in peripheral blood of rat. Methods: In this experimental study, sixty N-Mari rats were divided into three groups of 20 rats. Then the rats in each group were divided into four subgroups based on the blood sampling time that was 2, 6, 24 and 48 hours after the venom injection, respectively. The control group did not receive anything, however, the first and the second ex­perimental groups received 0.1 and 0.01mg/kg of venom, subcutaneously. In accordance with a designated four sam­pling times, the blood sampling was carried out in three groups. After RBC lysis, the leukocytes and leukocyte sub­populations were determined and counted using appropriate hematological standard methods. Results: The leukocyte and the neutrophil count at two (P<0.05), six (P<0.01) and 24 (P<0.05) hours after the venom injection showed a significant decline compared with the control group, this decrease was significant at the dose of 0.1 mg/kg until 48 hours after the venom injection (P<0.05). The lymphocyte count showed a significant decline throughout the all hours of the experiment, compared with the control group (P<0.05). Conclusion: Leukocytes are probably affected by the cytotoxicity effect of the H. lepturus venom in a dose-dependent manner. This could be a wakeup call for the medical staff to perform quick and accurate treatment in the least time possible. https://jad.tums.ac.ir/index.php/jad/article/view/145 https://jad.tums.ac.ir/index.php/jad/article/download/145/131