Effects of deferoxamine on brain injury after transient focal cerebral ischemia in rats with hyperglycemia

Abstract

Hemorrhagic transformation (HT) is a major factor limiting the use of tissue plasminogen activator (tPA) for stroke patients. This study examined the role of deferoxamine (DFX) in brain injury and HT in a rat model of transient focal ischemia with hyperglycemia. Rats received an injection of 50% glucose (6 mL/kg, i.p.) 15 min before undergoing transient middle cerebral artery occlusion (tMCAO; 2 h occlusion) with reperfusion. Rats were treated with DFX (100 mg/ kg, i.m.) or vehicle immediately after tMCAO. Rats were killed at 4, 8 and 24 h later and used for brain edema, blood-brain barrier permeability, hemorrhage volume, hemoglobin content, and infarct volume measurements. Mortality rate was also evaluated. DFX treatment reduced mortality at 24 h (4% vs. 24% in the vehicle-treated group, p<0.05). DFX also reduced infarct volume (85.1+/-56.3 vs. 164.3+/-93.4 mm(3) in vehicle, p<0.05) and swelling in the basal ganglia (p<0.05) 24 h after tMCAO. The total hemorrhage volume in the ipsilateral hemisphere at 8 h post tMCAO was less in DFX-treated animals (p<0.05). However, blood-brain barrier permeability was same in DFX- and vehicle-treated groups. DFX attenuates death rate, hemorrhagic transformation, infarct volume, and brain swelling in a rat transient focal ischemia with hyperglycemia model, suggesting that DFX could be potential treatment to reduce the hemorrhagic transformation for stroke patients.

Figure 1

Hematoxylin and eosin brain sections captured at magnification of 4x demonstrating the four portions: 1, pre-optic area, 2, basal ganglia, 3, lateral cortex and 4, cingulate cortex. B. Red blood cells contained in pockets of hemorrhage in the lower (a, scale bar= 100μm) and higher (b, scale bar=50μm) magnification and red blood cells contained within congested blood vessels at lower (c, scale bar=100μm) and higher (d, scale bar=50μm) magnification.

Figure 2

Coronal rat brain sections 8 (A, B) and 24 (C, D) hours after 2 hours transient middle cerebral artery occlusion with hyperglycemia treated with vehicle (A, C) or deferoxamine (B, D) with H-E staining. (E) Brain swelling measurements. Values are mean ± SD, n=6 in 8 hours group and n=7 to 9 in 24 hours group.

Figure 3

Hemorrhagic transformation 8 hours after 2 hours transient middle cerebral artery occlusion with hyperglycemia treated with vehicle (A-C) or deferoxamine (D-F). Scale bar: 100μm. (G) Hemorrhagic volume measurements. Values are mean ± SD, n=6 per group. *p<0.05.

Figure 4

Brain coronal sections in rats 24 hours after 2 hours transient middle cerebral artery occlusion with hyperglycemia. Rats were treated with vehicle (A) or deferoxamine (B) with cresyl violet staining. (C) Infarct volume. Values are mean ± SD, n=7-9, *p<0.05.

Figure 5

Neurological deficits in rats subjected to 2 hours of transient middle cerebral artery occlusion with hyperglycemia. Rats were treated with vehicle (A) or deferoxamine (B). Animals that died within the 14 days of the experiment were excluded from the analysis. Values are mean ± SD, n=6-8. There were no significant differences between the two treatments.