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Gene interference regulates aquaporin-4 expression in swollen tissue of rats with cerebral ischemic edema: Correlation with variation in apparent diffusion coefficient.

Hu H, Lu H, He Z, Han X, Chen J, Tu R - Neural Regen Res (2012)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Affiliated Haikou Hospital of Xiangya School of Medicine, Central South University (Haikou Municipal People's Hospital), Haikou 570208, Hainan Province, China.

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.

No MeSH data available.


Related in: MedlinePlus

Mitochondrial swelling and vacuoles (arrow) indicate intracellular edema in the ischemia group at 0.25 hours after middle cerebral artery occlusion (transmission electron microscopy, × 6 000).
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Figure 4: Mitochondrial swelling and vacuoles (arrow) indicate intracellular edema in the ischemia group at 0.25 hours after middle cerebral artery occlusion (transmission electron microscopy, × 6 000).

Mentions: Pathological changes in the ischemia group were the same as the control group. At 0.25 hours after MCAO in the ischemia group, a small amount of swollen glial cells with a round appearance, enlarged soma, and a light eosinophilic cytoplasm were observed under the optical microscope (Figure 3). At 0.25 hours after MCAO, mitochondrial swelling, vacuole-like changes, expanded endoplasmic reticulum, nuclear swelling and chromatin margination were observed under the electron microscope (Figure 4).


Gene interference regulates aquaporin-4 expression in swollen tissue of rats with cerebral ischemic edema: Correlation with variation in apparent diffusion coefficient.

Hu H, Lu H, He Z, Han X, Chen J, Tu R - Neural Regen Res (2012)

Mitochondrial swelling and vacuoles (arrow) indicate intracellular edema in the ischemia group at 0.25 hours after middle cerebral artery occlusion (transmission electron microscopy, × 6 000).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4308770&req=5

Figure 4: Mitochondrial swelling and vacuoles (arrow) indicate intracellular edema in the ischemia group at 0.25 hours after middle cerebral artery occlusion (transmission electron microscopy, × 6 000).
Mentions: Pathological changes in the ischemia group were the same as the control group. At 0.25 hours after MCAO in the ischemia group, a small amount of swollen glial cells with a round appearance, enlarged soma, and a light eosinophilic cytoplasm were observed under the optical microscope (Figure 3). At 0.25 hours after MCAO, mitochondrial swelling, vacuole-like changes, expanded endoplasmic reticulum, nuclear swelling and chromatin margination were observed under the electron microscope (Figure 4).

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Affiliated Haikou Hospital of Xiangya School of Medicine, Central South University (Haikou Municipal People's Hospital), Haikou 570208, Hainan Province, China.

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.

No MeSH data available.


Related in: MedlinePlus