Studying the Effect of Short Time Salinity on the Activity of Chloride Cells by Immunohistochemistry and Scanning Electron Microscopy in, Cyprinus carpio

The main purpose of the recent study was to evaluate gill chloride cells in Cyprinus carpio during adaptation to different environmental salinities over a short period.

For this research, Cyprinus carpio by an average weight of 41.4±1 g and length of 16.9±1 cm in four groups with three replications was used. The first group as control was located in fresh water and the next three groups respectively were kept in 4 ppt, 8 ppt, and 12 ppt salinity with the exact condition. On 0, 6, 12, 24, 48, 72, and 96 h the second-gill arch with a maximum thickness of 0.5 cm from the left side was prepared and placed in formalin’s buffer 10%, glutaraldehyde 2.5% solution, and pH 7.4. Then the standard method of preparing tissue sections was performed and paraffin sections with a thickness of 4-6 microns were prepared and stained with hematoxylin and eosin methods and examined with a light microscope. Also, changes in the structure and number of mitochondrial-rich cells, distribution, and dispersion of Na+/K+-ATPase enzyme were studied by scanning electron microscope and immunohistochemical technique.

Results showed obvious modifications in the number and distribution of chloride cells in two filament and lamellar positions at different sampling times. The highest number of chloride cells in the filament and lamella, 26.28±1.33; 19.11±1.27 was reported in 12ppt and the lowest number belonged to the control group. The largest size of chloride cells in the filament and lamella, 22.51±1.56; 12.72±1.32 was reported in 12ppt and the lowest size belonged to the control group.

The findings of this study showed that C. carpio gill chloride cells in the face of different salinities in a short period can change the number and size and adapt to the new condition.