Abstract:

Objective To investigate structural characteristics and functional significance of the renal tissue in the female and male soft-shelled turtles.Methods A total of 20 soft-shelled turtles were used in this study. Toluidine blue staining and transmission electron microscopy were used to observe structural differences of renal tissue between the female and male soft-shelled turtles. Results There were some differences in epithelial cell structure in the proximal tubules and intermediate segments between male and female turtles. The lateral intercellular spaces and basal intercellular spaces occurred in epithelial cells of turtle proximal tubule and intermediate segments in the male soft-shelled turtles, and some slender finger-like projections were distributed in lateral intercellular space. Basal labyrinthes were found in basal intercellular spaces. However there was no space among epithelial cells of proximal tubule and intermediate segments in the female turtles. In addition, male proximal tubule epithelial cells composed with primary cells, bald cells and basal cells, while female proximal tubule epithelial cells composed with only two kinds of epithelial cells, the bright cells and dark cells.Conclusion The structural differences of epithelian tissues of renal proximal tubule and the intermediate segments exist between female and male soft-shelled turtles. The lateral intercellular spaces and basal intercellular spaces appeare in male turtles, but not in female turtles. Since the lateral intercellular spaces and basal intercellular spaces involve in material transport, the results suggest that the urine reabsorption capacity in proximal tubule and the urine concentrating ability in intermediate segment may be stronger in male soft-shelled turtles than that in female turtles.

Key words: Kidney, Fine structure, Sex difference, Transmission electron microscopy, Pelodiscus sinensis