The Effects Of Restraint Water-Immersion Stress On CRH Signaling Pathways In Hypothalamus, Medulla Oblongata And Sacral Region Spinal Cord In Rats

The rat restraint water- immersion stress( RWIS) model is widely used to study the pathogenesis of stress-induced gastric lesions and to filtrate the medicine to cure this disease. Recent studies show that the gastric dysfunctions induced by RWIS were mainly due to the brain neuronal activities and mediated by the parasympathetic fibers.According to our previous studies , compared with control group, the number of Fos protein expression positive cells in the hypothalamic paraventricular nucleus(PVN),supraoptic nucleus(SON) and dorsal vagal complex(DVC) was significantly increased during the RWIS, which revealed that the neurons in the PVN,SON and DVC were activated during the RWIS process. But it is unknown that if the neurons in sacral region spinal cord participate in the RWIS.CRH is an important stress hormone, more and more researches reported that it paticipates in many kinds of stress model,such as fixed stress, avoidance water stress and so on, whether the CRH plays a role in the RWIS, no researches have been reported. In order to study the effects of CRH during RWIS , this research is divided into three parts: Part 1. To explore the best way to display the CRH neurons in the central neurous system.In order to find out a more reasonable method,we compared the two kinds of colchicine injection methods (intracerebroventricular injection,intraperitoneal injection and control group).The results showed that compared with the control group, the CRH neurons were much clearer in both intracerebroventricular injection group and intraperitoneal injection group. Many researches have used the method of intracerebroventricular injection of colchicine to study the effects of CRH in PVN. However, intracerebroventricular injection is a kind of serious pathological damage.On the whole intraperitoneal injection was better. Part 2. The Fos positive neurons in the sacral region spinal cord were displayed during the RWIS.The results showed that compared with the control group,the IOD and the number of Fos positive neurons in the sacral spinal cord increased significantly(P<0.05) during the RWIS.The results suggested that the neurons in the sacral spinal cord might more activated during the RWIS.Part 3. We studied the effects of CRH neurons and Fos/CRH-IR double-labeled neurons in hypothalamic, medulla oblongata and sacral spinal cord during the RWIS . The CRH neurons and Fos/CRH-IR double-labeled neurons were displayed with immunocytochemical technique and the results were analyzed with the microscopic image analysis system. In our study, both of the CRH neurons celles and fibers were found in the PVN,DVC and sacral spinal cord, but in the SON only CRH fibers could be seen. Moreover,compared with the control group,the IOD of CRH neurons and the number of Fos/CRH-IR double-labeled neurons increased significantly (P<0.05) in the PVN,DVC and sacral spinal cord. These results suggested that the activity degrees of CRH neurons in the hypothalamic,medulla oblongata and sacral spinal cord are stronger during the RWIS.According to the results above,we can concluded that neurons in the PVN,DVC and the sacral spinal cord were significently activitied during RWIS. And the CRH neurons in the PVN,DVC and sacral spinal cord might play an important role in the prosess of RWIS,and of course,much more reseaches should be taken next.