| Objective:The paper is to study the morphological changes of dorsal root ganglion (DRG) on the basis of the different ischemia and reperfusion of mice. Besides, in order to provide the morphological data for the mechanism of the injury of the ischemia and reperfusion and to provide the basic information for the clinical treatment of the ischemia and reperfusion, the paper is also to observe the cell injury of the DRG, caused by the ischemia in different time, from the viewpoint of the ultrastructure.Methods:By using the model of occlusion and reperfusion of common iliac arteries of the mice, we observe the morphological changes of the DRG in different period of time of the ischemia and reperfusion, and we pay special attention to the changes of neuron of the DRG.Male Kunming mice (12week, 20-25g ) are randomly divided into 6 groups with different treatments:1) Sham-treated Control Group (Group A, n=6). The group is only to be found the common iliac arteries.2) IPC Groups (Groups B, C, D). Group B (n=6) is the control group. After finishing the above procedure, continuously we should keep the common iliac arteries of the mice in the clamped state for 10 minutes and then keep them in the de-clamped state for 5 minutes. Do the same treatment once more.3) Group C (n=8). Group C, 24 hours after that treatment of Group B, is to be kept in the clamped state for 6 hours, and then to be kept in the de-clamped state. The cut should be sutured finally.4) Group D (n=8). Similar to Group C, Group D, 24 hours free from that treatment of Group B, is to be clamped for 8 hours, and then to be de-clamped. The cut should also be sutured finally.5) Ischemia and Reperfusion Groups (Groups E, F). Group E (n=6), after being found the common iliac arteries, is immediately to be clamped for 6 hours, and then to be de-clamped. The cut should be sutured finally.6) Group F (n=6). Similar to Group E, Group F, after being found the common iliac arteries, is immediately to be clamped for 8 hours, and then to be de-clamped. The cut should also be sutured finally.One point should be emphasized that all the mice should be put to death after 50 hours of the above treatments. Only after that, could the lumbar DRG be cut off. Then, they are examined under light microscopes and electron microscopes. Finally, the tissue slice should be dyed HE and TUNEL.Results:1. We have observed the ultrastructure of normal mice's DRG.2. The mice's hindlimb ischemia and reperfusion can cause the morphological changes of the DRG.By observing the DRG of the mice under light microscopes and electron microscopes, we can seeGroup A: normal structure.Group B: light changes in cell.Groups C, D, E, F: Under light microscopes and electron microscopes, it has been found that the longer the mice suffer from the ischemia, the more severe the neuron injuries are. Meanwhile, there appear the changes of cells, shrinkage of cytoplasm, neuron pyknosis, nuclear dissolve, increase of satellite cells, micrangiumenlargement, apoptosis, and necrosis.In the same ischemia time, Groups C and E, Groups D and F, the two different groups have been found that the injuries of the IPC group are more severe than those of the non- IPC group under the microscopes. As a result, we come to the conclusion: Instead of having the protective effects on the DRG, the ischemia IPC leads to more injuries of the DRG. In addition, compared with Group D, Group C has more injuries, which illustrates that the functions of the DRG of the mice will not in the normal state, though after 24 hours of the IPC. Being clamped once more for 6 hours and then being de-clamped once more would result in more severe injuries in physiology than being clamped only once and then being de-clamped for 8 hours.3. Physiological changes of apoptosis cells in Groups C, D, E, F have been observed under the electron microscope, and the same as TUNEL dyeing.Conclusion:The longer the mice surfer from the ischemia, the more severe the neuron injuries are; Instead...
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