Neuroprotective effects of PACAP38 in a rat model of transient focal ischemia under various experimental conditions.

In the study reported here, we investigated the neuroprotective effect of PACAP38 in a rat model of middle cerebral artery occlusion (MCAO) under various experimental conditions. Stroke patients often develop mild hyperthermia that increases the infarct size and worsens the outcome. We compared the neuroprotective effect of PACAP38 in normothermic and moderately hyperthermic animals. Brain damage was more extensive in the hyperthermic animals, but PACAP38 significantly reduced the infarct size, measured 48 h after MCAO, in both the normothermic and the moderately hyperthermic animals, by more than 50%. However, a significant neuroprotection with PACAP38 could only be demonstrated when animals with no definite circling behavior and/or convulsions were excluded from the evaluations. In conclusion, moderate hyperthermia did not influence the effect of PACAP38, but animals with questionable brain damage or convulsions must be excluded from the sample in order to demonstrate the neuroprotection with PACAP38.