title: Gene interference regulates aquaporin-4 expression in swollen tissue of rats with cerebral ischemic edema: Correlation with variation in apparent diffusion coefficient.
abstract: To investigate the effects of mRNA interference on aquaporin-4 expression in swollen tissue of rats with ischemic cerebral edema, and diagnose the significance of diffusion-weighted MRI, we injected 5 μL shRNA- aquaporin-4 (control group) or siRNA- aquaporin-4 solution (1:800) (RNA interference group) into the rat right basal ganglia immediately before occlusion of the middle cerebral artery. At 0.25 hours after occlusion of the middle cerebral artery, diffusion-weighted MRI displayed a high signal; within 2 hours, the relative apparent diffusion coefficient decreased markedly, aquaporin-4 expression increased rapidly, and intracellular edema was obviously aggravated; at 4 and 6 hours, the relative apparent diffusion coefficient slowly returned to control levels, aquaporin-4 expression slightly increased, and angioedema was observed. In the RNA interference group, during 0.25-6 hours after injection of siRNA- aquaporin-4 solution, the relative apparent diffusion coefficient slightly fluctuated and aquaporin-4 expression was upregulated; during 0.5-4 hours, the relative apparent diffusion coefficient was significantly higher, while aquaporin-4 expression was significantly lower when compared with the control group, and intracellular edema was markedly reduced; at 0.25 and 6 hours, the relative apparent diffusion coefficient and aquaporin-4 expression were similar when compared with the control group; obvious angioedema remained at 6 hours. Pearson's correlation test results showed that aquaporin-4 expression was negatively correlated with the apparent diffusion coefficient (r = -0.806, P < 0.01). These findings suggest that upregulated aquaporin-4 expression is likely to be the main molecular mechanism of intracellular edema and may be the molecular basis for decreased relative apparent diffusion coefficient. Aquaporin-4 gene interference can effectively inhibit the upregulation of aquaporin-4 expression during the stage of intracellular edema with time-effectiveness. Moreover, diffusion-weighted MRI can accurately detect intracellular edema.
authors: Department of Radiology, Affiliated Haikou Hospital of Xiangya School of Medicine, Central South University (Haikou Municipal People's Hospital), Haikou 570208, Hainan Province, China.
authors: Hui
authors: H
authors: Hu
authors: Department of Radiology, Affiliated Haikou Hospital of Xiangya School of Medicine, Central South University (Haikou Municipal People's Hospital), Haikou 570208, Hainan Province, China.
authors: Hong
authors: H
authors: Lu
authors: Department of Radiology, Affiliated Haikou Hospital of Xiangya School of Medicine, Central South University (Haikou Municipal People's Hospital), Haikou 570208, Hainan Province, China.
authors: Zhanping
authors: Z
authors: He
authors: Department of Radiology, Affiliated Haikou Hospital of Xiangya School of Medicine, Central South University (Haikou Municipal People's Hospital), Haikou 570208, Hainan Province, China.
authors: Xiangjun
authors: X
authors: Han
authors: Department of Radiology, Affiliated Haikou Hospital of Xiangya School of Medicine, Central South University (Haikou Municipal People's Hospital), Haikou 570208, Hainan Province, China.
authors: Jing
authors: J
authors: Chen
authors: Department of Radiology, Medical College of Hainan Province, Haikou 570102, Hainan Province, China.
authors: Rong
authors: R
authors: Tu
keywords: aquaporin-4; cerebral ischemic edema; diffusion; gene silencing; mRNA interference; magnetic resonance imaging; neural regeneration
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