Delayed formation of hematomas with ethanol preconditioning in experimental intracerebral hemorrhage rats

Spontaneous intracerebral hemorrhage (ICH) accounts for 10%-15% of all strokes and causes high mortality and morbidity. In the previous study, we demonstrated that ethanol could aggravate the severity of brain injury after ICH by increasing neuroinflammation and oxidative stress. In this study, we further investigate the acute effects of ethanol on brain injury within 24 h after ICH.

Totally, 66 male Sprague-Dawley rats were assigned randomly into two groups: saline pretreatment before ICH (saline + ICH), and ethanol pretreatment before ICH (ethanol + ICH). Normal saline (10 mL/kg) or ethanol (3 g/kg, in 10 mL/kg normal saline) was administered intraperitoneally 1 h before induction of experimental ICH. Bacterial collagenase VII-S (0.23 U in 1.0 μL sterile saline) was injected into the right striatum to induce ICH in the rats. We evaluated the hematoma expansion, hemodynamic parameters (heart rate and blood pressure), activated partial thromboplastin time (aPTT), prothrombin time (PT), and striatal matrix metallopeptidase 9 (MMP-9) expressions at 3, 6, 9, and 24 h after ICH.

The ethanol + ICH group exhibited decreased hematoma at 3 h after ICH; nevertheless, there was a larger hematoma compared with the saline + ICH group at 9 and 24 h after ICH. The ethanol + ICH group had lower blood pressure at 3, 6, and 9 h post-ICH, but both groups maintained similar heart rates after ICH. There was no significant difference in the aPTT and PT between the two groups. Incremental ethanol concentrations had no influence on collagenase VII-S activity at 120 min in vitro. MMP-9 expression was upregulated in the right striata of the ethanol + ICH group, especially at 3 and 9 h after ICH.

Ethanol delayed hematoma formation in the first 3 h due to a hypotensive effect; however, the accelerated growth of hematomas after 9 h may be a sequela of ethanol-induced MMP-9 activation.