The epithelial cytotypes of hepatopancreas in the Chinese mitten crab Eriocheir sinensis (Decapoda, Varunidae)

Abstract

The Chinese mitten crab,Eriocheir sinensis, is an economically important crustacean. However, the hepatopancreas structure of the crab has not been fully disclosed. Here, we employed light microscopy and transmission electron microscopy to identify the epithelial cytotypes of the hepatopancreas. The hepatopancreas consisted of four epithelial cytotypes, which were B (blister-like), R (resorptive), F (fibrillar), and E (embryonic) cells. B cells had club-shaped nuclei, scant cytoplasm, and contained some small vacuoles and one extremely large vacuole. Both R and F cells were columnar, and F cells were separated by two to three serial R cells. R cells contained small vacuoles, but had no extremely large vacuole in the cytoplasm. Two neighbouring R cells established contact by septate junctions. Many microvilli were present on the surface of the plasmalemma of R cells. Endocytotic vesicles were frequently observed in apical regions of the R cells. F cells were hyperbasophilic and argyrophilic, and contained abundant rough endoplasmic reticulum. E cells were small and contained scant cytoplasm and we rarely observed organelles in these cells. In addition, many vesicae were present in the lumen of the hepatopancreatic tubules.