Comparing white and gray matter responses to lobar intracerebral hemorrhage in piglets and the effects of deferoxamine

Background

Intracerebral hemorrhage (ICH) often impacts patient white matter. However, preclinically, the effects of ICH are mostly studied in rodents with sparse white matter. This study used a lobar porcine ICH model to examine differences in the effects of ICH on white and gray matter as well as the role of the iron chelator deferoxamine (DFX), on attenuation of such injury.

Methods

This two-part study was performed in piglets. Firstly, piglets had a needle (Sham) or 2.5 ml blood injection (ICH) and were euthanized at day 3. Secondly, animals were treated with vehicle or DFX after ICH and were euthanized at day 3. White and gray matter edema, the number of oligodendrocytes (mature and immature) and neurons, and the number of Perls' (iron), ferritin and heme oxygenase (HO)-1 positive cells were examined.

Results

At day 3, ICH induced greater edema formation in white than gray matter. This marked white matter edema was associated with a loss of mature, but not immature, oligodendrocytes. ICH also induced neuronal death in gray matter. There were also marked increases in Perls', ferritin and HO-1 positive cells after ICH in both white and gray matter, but significantly more in the former. DFX attenuated ICH-induced brain edema in white but not gray matter and this was associated with increased survival of mature oligodendrocytes. DFX also increased survival of neurons in the gray matter and it reduced the number of Perls', ferritin and HO-1 positive cells in both tissue types.

Conclusions

While there were commonalities in perihematomal changes between white and gray matter after ICH, there was greater edema in white matter which may be linked to the susceptibility of mature oligodendrocytes to ICH injury. Similarly, while DFX reduced perihematomal iron overload in both white and gray matter, it only significantly reduced edema in white matter where it increased the number of mature oligodendrocytes.