Water treadmill training promotes the polar expression of aquaporin 4 and reduces tissue edema after spinal cord injury in rats
XIE Qingfeng, XIE Yuanyuan, Hu Quan, Chen Xiaolong, Lin Jianwei, YING Xinwang.
Center of Physical Medicine and Rehabilitation, the Second Affiliated Hospital & Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou 325027, China
XIE Qingfeng,XIE Yuanyuan,Hu Quan, et al. Water treadmill training promotes the polar expression of aquaporin 4 and reduces tissue edema after spinal cord injury in rats[J]. JOURNAL OF WEZHOU MEDICAL UNIVERSITY, 2023, 53(6): 450-457.
Abstract：Objective: To explore the mechanism of water treadmill training (TT) in the spinal cord edema after spinal cord injury (SCI) in rats. Methods: Rats were randomly divided into Sham operation no treatment group (Sham-Con), Sham operation exercise group (Sham-TT), spinal cord injury group (SCI-Con) and spinal cord injury exercise group (SCI-TT). The rats in the exercise group were treated with TT intervention, and the rats in each group were evaluated with Bssso Beattie Bresnahan (BBB) Test on the 1st, 3rd, 7th and 14th day after operation. The moisture content of the spinal cord was detected by wet and dry weight method, the bloodspinal barrier permeability was detected by Evans bule (EB) staining, and the expressions of aquaporin 4 (AQP4) and glial fibrillary acid protein (GFAP) in the surrounding tissues of the spinal cord were detected by Western blot. The co-labeling of platelet-endothelial cell adhesion molecule (CD31)/AQP4/GFAP/DAPI was detected by immunofluorescence three-label staining, and the presence of AQP4 on endothelial cells (ECs) in each group was detected by immunoelectron microscopy. Results: There was no statistical significance (P>0.05) between Sham-Con group and Sham-TT group in water content in spinal cord, EB content in tissue, polar expression of AQP4, total protein expression and BBB scores. After SCI, the water content of spinal cord in SCI-Con group was significantly increased (P<0.05), the content of EB in tissue increased (P<0.05), the expression of GFAP protein up-regulated (P<0.05), and the polarity expression of AQP4 increased. However, there was no statistical
significance in the expression level of total AQP4 protein compared with Sham-Con (P>0.05). TT could reduce tissue edema after SCI (P<0.05), decrease the permeability of blood-spinal barrier (P<0.05), and further increase the polarity expression of AQP4 (P<0.05), and promote the recovery of motor function in rats at 7 d and 14 d (P<0.05). But there was no significant effect on the total protein expression of AQP4 (P>0.05). Conclusion: TT can reduce tissue edema after SCI in rats, and its protective mechanism may be related to the promotion of the polarity expression of AQP4.
