Effect Of High Temperature And Heavy Metal Copper Stress On Zebrafish Rodlet Cell

Rodlet cell(RC)is a type of cell found only in teleost fish,and may be a special type of cell associated with nonspecific immunity in fish.Although the research on RC has been going on,its source and function are always controversial.High temperatures and the heavy metal copper threaten fish living in natural waters and affect their immune system.In this paper,zebrafish were used as experimental animals to observe the morphological structure and distribution characteristics of RC in zebrafish.On this basis,the changes of RC in zebrafish under high temperature and heavy metal copper stress were further explored.Experiment 1 Morphology and distribution characteristicsThrough light microscopy and electron microscopic observation of RC in zebrafish,and analyze its morphological characteristics and distribution rule.The results show that the morphological characteristics of RC are very distinct.RC mainly distributes in the epithelial tissues of gill,intestine and kidney as well as skin.Unlike other cells.A thick fibrous shell is formed on the inside of the cell membrane of RC.The position of the nucleus in the cell is relatively fixed and is located at the base of the cell.There is a special organelle in the cytoplasm,which is a baseball rod and is called rodlet.The rodlet is covered with a film,high electron density in the center,low electron density around it.The development of RC can be divided into four stages:immature stage,transition stage,mature stage and release stage.In immature RC,the fibrous shell is thinner,there is no typical rodlet,but there are a large number of rough endoplasmic reticulum.In the transitional stage of RC,the fibrous shell became thicker gradually,the rodlet appeared gradually,and the rough endoplasmic reticulum decreased gradually.In the mature stage of RC,there are a lot of rodlet in the cytoplasm.The rodlet have complete structure,and the cells show typical RC morphological structure.In the release stage of RC,rodlet in the cytoplasm and part of the cytoplasm are released from the cells.The results reveal the morphological characteristics of zebrafish RC under electron microscopy and light microscopy,which lays a foundation for subsequent experiments.Experiment 2 Effect of high temperature stress on RCZebrafish were exposed to high temperatures of 34 degrees Celsius.The tissues were treated by whole fish immobilization,embedding and slicing at 0 h,3 h,6 h,12 h,24 h,48 h and 96 h after the experiment.After dyeing,the distribution of RC was observed under optical microscope,and the density of RC was counted.The results showed that RC could be observed in intestine,kidney,skin and gill.However,it has not been found in other tissues and organs,such as liver and reproductive organs.Compared with the control group,the morphological structure of RC in the treated group did not change significantly,and all showed typical RC morphological characteristics.Compared with the control group,the distribution density of RC increased significantly during the experiment.The density of RC in the body kidney peaked at 12 h.The density of RC in the intestine reached its first peak at 3 h and then reached its second peak at 48 h.The density of RC in the skin peaked at 6 h.The density of RC in the surimi reached a peak at 3 h.The cell density of RC in fish is significantly increased at high temperatures,indicating that the distribution density of RC can be used as a measure of environmental changes.Experiment 3 Effect of heavy metal-Cu stress on RCPlace the zebrafish in an aqueous environment with a CuSO4 concentration of 1 mg/L.At 0 h,3 h,6 h,12 h,24 h,48 h,and 96 h after the test,the tissues were treated with whole fish fixation,embedding,and sectioning.After dyeing,the distribution of RC was observed under an optical microscope,and the variation of density of RC was counted.The results showed that RC could be observed in intestine,kidney,skin and gill.However,it has not been found in other tissues and organs,such as liver and reproductive organs.Compared with the control group,the morphological structure of RC in the treated group did not change significantly,and all showed typical RC morphological characteristics.Compared with the control group,the distribution density of RC increased significantly during the experiment.The density of RC in the body kidney peaked at 24 h.The density of RC in the intestine reached a peak at 12 h.The density of RC in the skin reached its first peak at 3 h and then reached its second peak at 12 h.The density of RC in the surimi reached its first peak at 6 h and then reached its second peak at 96 h.In a high CuSO4 concentration environment,the cell density of RC in fish is significantly increased,indicating that the distribution density of RC can be used as a potential indicator for detecting water pollution.