Effects of dexamethasone on leukocytic responses in pregnant Yankasa ewes and Sahel does in Maiduguri, Nigeria

Abstract

Effects of dexamethasone on leukocytic responses of pregnant Yankasa sheep and Sahel does were investigated. In addition to its anti-inflammatory properties, dexamethasone regulates broad variety of immune cell functions and immune mediator expression at the molecular level and has become subject of considerable interest in clinical immunology. It has been shown to cause leukocytosis involving neutrophilia, suppression of leukocyte blastogenesis and change lymphocyte subpopulation patterns. However, response to medication may differ among species and physiological status. The objective of the study was to compare and evaluate the effects of dexamethasone on leukocytic responses in pregnant Yankasa ewes and Sahel does. Fourteen adult Sahel goats comprising 12 does and 2 bucks and 14 Yankasa ewes comprising of 12 ewes and 2 rams were used for this study. Pregnancies were achieved by natural mating after synchronization. Repeated dexamethasone injection was given at 0.25mg/kg body weight. Blood samples were collected on biweekly basis from each animal through the jugular vein on the same day with minimal excitement prior to feeding. Samples collected were used for the analysis of total white blood cell counts (WBC) and differential leukocyte counts (DLC) (neutrophils, eosinophils, lymphocytes, monocytes and basophils). Dexamethasone significantly (P<0.05) increased total WBC and neutrophil counts in both pregnant Yankasa ewes and Sahel does, but decreased lymphocyte counts in both species. The leukocytic responses of pregnant Yankasa ewes and Sahel does to dexamethasone treatment were similar to reports by other workers in non-pregnant subjects. It was concluded that both species were sensitive to lymphopenic effects of dexamethasone and that pregnancy did not increase the susceptibility of the dam to dexamethasone with regard to leukocytic parameters.

Keywords: Dexamethasone, Leukocytosis, Pregnant, Sahel does, Yankasa ewes