Suppression of Aquaporin-4 By Antisense Oligonucleotides Reduces Brain Edema In Experimental Traumatic Brain Injury.

Aim: In this study, suppression of Aquaporin-4 (AQP4) synthesis via intracerebroventricular (i.c.v.) injection of antisense oligonucleotide after focal cortical contusion injury in mice was investigated.

Material And Methods: 12-week female Swiss albino mice of 20-25 g were used to create a focal cortical contusion model by the weight drop method (35 grams blunt weight, 70 cm height) onto the parietal cortex after craniectomy. The sham group underwent craniectomy without trauma. In the control group, weight was dropped onto the parietal cortex immediately after Dulbecco\'s Modified Eagle Medium (DMEM) i.c.v. injection following craniectomy. In addition, 1 nM of aquaporin-4 (AQP4) antisense oligonucleotide (ASO) was injected via i.c.v route immediately after trauma (0 hours) and 4 hours after trauma. All animals underwent magnetic resonance (MR) imaging and were sacrificed at 24 h. Brain water content was determined using the wet/dry weight method.

Results: In the sham group, the average percentage of brain water content was 77.75% compared to the control group with 79.87%. The difference was statistically significant (*p=0.017). In the therapy group, the average was 78.81% and significantly reduced compared to the control group (*p=0.026) at 0 hours. In the 4-hour treatment group, the average of 79.11% was not statistically significant (p=0.39). MR imaging findings also showed a substantial reduction in brain edema in the 0-hour treatment group. However, the 4-hour treatment results, when compared with the control trauma group, did not show a significant difference.

Conclusion: This study demonstrated that AQP4 antisense oligonucleotide therapy, when administered early after diffuse traumatic brain injury, leads to a significant reduction in brain edema.