Changes occurring in the receptors of blood neutrophils during implantation in Sahiwal cows

Abstract

Neutrophils are considered to be the first line of defence against any external invasion. To study the number of neutrophils and expression of adhesion receptors during implantation of an embryo in the mothers endometrium.  Blood samples were collected from 15 Sahiwal cows on the day of Artificial Insemination (A.I.) (day 0), and on day 18 post A.I. (day of implantation).  Total leucocyte counts (TLC), number and type of neutrophils were observed under light microscopy, whereas, neutrophils receptors were observed by flow cytometry.  Cows were divided into pregnant (P) and non-pregnant (NP) groups once they were confirmed pregnant after estimation of plasma progesterone (on day 18) and also by rectal palpation (on day 60). Higher (P<0.05), TLC and neutrophil percentage was observed during early pregnancy in P cows on day 18^th of A.I.. The surface receptor expression of CD62L and CD11B by flow cytometry showed significantly lower (P<0.05) expression of these receptors on day 18^th in P cows. From this study it was concluded that more neutrophils are released during circulation in both P and NP cows, but more surface receptor on the surfaces of NP cows increase the overall activity of their neutrophils and thus prevents implantation of the embryo in them.