Behavioral characterization of the anterior injection model of subarachnoid hemorrhage

The applicability of various neurological scores has not been sufficiently characterized in the anterior injection model of subarachnoid hemorrhage (SAH). Therefore this study was performed to evaluate different behavioral tests for quantifying disease severity.

Different volumes of autologous blood were injected stereotaxically into the prechiasmatic cistern of mice. Sham controls underwent the same procedure without blood injection. The following seven days after surgery, mice were evaluated for behavioral deficits by the SHIRPA score, beam balance and flex field analyses. Brains were further processed for histological analyses.

Flex field analysis of SAH animals showed a significant reduction of locomotor activity compared to controls in the first two days after SAH. This reduction was more intense in animals with a higher amount of injected blood. The SHIRPA score revealed a significant reduction in motor behavior in SAH animals two days after surgery. A significant increase of GFAP expression, Fluoro Jade C and TUNEL positive cells as well as microthrombi was observed in SAH animals compared to sham controls in the early phase of SAH. There was a significant negative correlation between flex field righting and the number of degenerative neurons or microthrombi in the first two days after SAH.

The results of flex field analysis and SHIRPA single test show behavioral and functional deficits in the first two days after SAH in parallel to histological alterations indicating neuronal damage. In summary these tests can be used as functional outcome parameters in the anterior injection model of SAH.