Intracerebral hemorrhage (ICH)-induced white matter injury has not been well studied. The objective of this study was to examine the effect of zinc protoporphyrin (ZnPP) on white matter injury induced by ICH. This study was divided into two parts. In the first part, rats received either a needle insertion (sham) or 100 μl autologous blood into the right basal ganglia. The rats were euthanized at 1, 3, 7, 14, or 28 days later for myelin basic protein (MBP) measurement. In the second part, rats had intracerebral infusion of 100 μl autologous blood, and an intraperitoneal osmotic mini-pump was implanted immediately after ICH to deliver vehicle or ZnPP (1 nmol/h), a heme oxygenase inhibitor, for up to 14 days. Rats were euthanized at day 28 for MBP staining. The number of MBP-labeled fiber bundles and their area were determined. The time-course showed that the white matter was lost in the ipsilateral basal ganglia from day 1 to day 28 after ICH. The number of MBP-labeled bundles and their area were significantly lower 2 weeks after ICH compared with sham-operated rats (p < 0.05). Systemic treatment with ZnPP attenuated the loss of MBP-labeled bundles (p < 0.01) and area (p < 0.01). In conclusion, marked white matter injury occurs after ICH. ZnPP reduces white matter injury, suggesting a role of heme degradation products in ICH-induced white matter damage.
Keywords: Heme oxygenase; Intracerebral hemorrhage; White matter injury; Zinc protoporphyrin.