Effect of season on morphology of hematopoietictissue in carp (Cyprinus carpio) fish.

摘要

Kidneys were excised from carp during winter (n=8) and summer (n=8) to determine effect of season on morphology of hematopoietic tissue. Samples were fixed in 10% neutral buffered formalin for 2 days for routine histology stained by hematoxylin, Eosinand PAS. Hematopoietic tissue was mainly concentrated in the dorsal kidney but the caudal kidney had smaller areas of hematopoietic cords or cell islands with sinusoidal capillaries. A high number of mitotic figures were noticed especially in summer time indicating active hemopoiesis with several cell lines wherein nuclei appeared large, spherical, euchromatic, with 2-3 apparent nucleoli. Different sized nuclei with nucleoli were present whereas cytoplasm appeared undeveloped or incomplete. A great number of active macrophages were clearly noticed. Large Proerythroblast Rubriblast with loose, lacy chromatin, observable nucleoli, and basophilic blue stained cytoplasm was evident. Megakaryocytes with highly lobulated nucleii were also present. The presence of large number of active macrophages indicates their important role in the process of hemopoiesis. The findings suggest that proliferation of pluripotent stem cells was more evident in fish collected during summer compared with those taken at winter. However, in all tissue samples, we found little cellular differentiation.