Megakaryocytes and platelets in the spleen of the dromedary camel (Camelus dromedarius).

Abstract

This study was carried out on spleens of clinically healthy camels (n = 35) of both sexes (0.5-15 years) by routine histology, electron microscopy and immunohistochemistry using 12 anti-bovine platelet antibodies. Megakaryocytes were observed in the red pulp. Their number decreased with age: they were found in the spleens of all camels under 8 years old but only in 57% of camels over 8 years old. Only two antibodies (IVA37 and IVA38) cross-reacted with camel platelets. A large number of platelets were found in the splenic cords and the marginal zone. Ultrastructurally, the platelets were oval in shape surrounded by a plasma membrane, and their cytoplasm was rich in glycogen and contained less dense granules. Microtubules and microfilaments were found at their periphery. Several platelets were observed in the red pulp. There are similarities in some surface antigens of bovine and camel platelets. The presence of megakaryocytes in the camel spleen indicates a thrombopoietic function of the spleen until adulthood but that this decreases with age thereafter.