The effect of restraint stress in pregnant rats on blood parameters of their offsprings.

Introduction: Stress has many effects on the development of systems and organs in the fetal period, and these effects appear after birth. Since hemopoietic system is susceptible to stress, effects of restraint stress were studied in offspring of pregnant rats. Methods: Pregnant rats were divided into one control and three stress groups. The control group did not receive any stress during the gestational period. Stress groups 1, 2 and 3 were subjected to restraint stress from 8 to 21, 8 to 17, and 17 to 21 days of gestation, respectively. At the age of 60 days, the blood samples were taken from the male offspring rats. Results: The results in the offsprings were as follows: a) Restraint stress markedly decreased the total number of white blood cells in offsprings of groups 1 and 3 . The percentage of granulocytes decreased and lymphocytes increased significantly in these groups. b) The number of red blood cells increased significantly in groups 1 and 2 compared with the control group. c) The number of platelets increased in group 1, although their hemoglobin decreased significantly. d) As for the index of RBC, the prenatal stress had an effect on MCV, MCH and MCHC in all groups. Conclusion: Our results showed that prenatal restraint stress causes long lasting changes in the blood parameters after birth. These data prove that restraint stress alters the function of immune and hemopoietic systems.