Prognostic models are used to predict outcome in
stroke patients and to stratify treatment groups in clinical trials. No one has previously attempted to use such models in
stroke recovery studies in animals. We have now shown the predictive value of assigning
stroke severity ratings, based on behaviours displayed in conscious rats during infusion of
endothelin-1 to constrict the middle cerebral artery, on neurological and histological outcomes. The validity of prior stratification of treatment groups according to
stroke ratings was tested by assessment of the protective potential of synthetic
flavonol,
3',4'-dihydroxyflavonol (DiOHF). Neurological deficits and performance on the sticky label test were evaluated before and at 24, 48 and 72 h post-
stroke. Histopathology was assessed at 72 h. Positive correlations between
stroke ratings and neurological deficit scores were found at 24 (r=0.58, P<0.001), 48 (r=0.53, P<0.001) and 72 (r=0.56, P<0.001) h post-
stroke, with more severe
strokes associated with worse deficit scores. Similar correlations were observed with the sticky label test. Higher
stroke ratings also correlated with greater
infarct volumes (total
infarct volume: r=0.74, P<0.0001). Treatment with DiOHF (10 mg/kg i.v. given 3, 24 and 48 h post-
stroke) significantly reduced
infarct volume and restored neurological function in rats with modest
stroke ratings (P<0.01), but not in rats with high
stroke ratings. These results suggest that
stroke ratings, based on behavioural assessment as the
stroke develops, reliably predict histopathological and functional outcomes and allow stratification of treatment groups. DiOHF given after
stroke improves outcomes in moderate
strokes, and therefore has cytoprotective potential.