Effect of acute and chronic stress on leucocyte count: modulation by chlordiazepoxide.

Total and differential leucocyte count (TLC and DLC) in blood circulation influence humoral immune response and stress alters TLC and DLC by leucocyte misdistribution. Chlordiazepoxide, a widely used benzodiazepine anti-stress agent, is reported to reverse suppression of antibody response induced by acute stress but not by chronic stress. The effect of chlordiazepoxide on the changes in leucocyte count by acute and chronic stress has not been clearly defined. We examined the effect of restraint stress (1 h/day) for 6, 10, 14 and 21 days on TLC and DLC and their modulation by chlordiazepoxide pretreatment (10 mg/kg/day) 1 h before exposure to stress in albino rats. Acute stress, i.e. restraint stress (1 h/day) for 6 and 10 days with or with out chlordiazepoxide pretreatment did not alter TLC and DLC. Chronic stress, i.e. restraint stress (1 h/day) for 14 and 21 days significantly decreased TLC and the percentage of lymphocytes in comparison to control. Pretreatment with chlordiazepoxide reversed these changes. We conclude that chlordiazepoxide, a benzodiazepine, reverses changes in TLC and DLC probably by improving chronic stress-induced leucocytes misdistribution.