Decreased beta-actin mRNA expression in hyperglycemic focal cerebral ischemia in the rat.

beta-Actin is often used as a housekeeping gene when performing reverse transcription-polymerase chain reaction (RT-PCR) analysis for cerebral ischemia models. In the present study, we tested two different control genes used for RT-PCR experiments, beta-actin and porphobilinogen deaminase (PBG-D), in a rat model of focal cerebral ischemia under normo- or hyperglycemic conditions. A three-vessel occlusion model with permanent middle cerebral artery occlusion was used in the rat. beta-Actin mRNA expression was decreased in hyperglycemic ischemic rats compared to normoglycemic ischemic animals 3 h post-ischemia. beta-Actin protein content was unchanged. As for PBG-D, its mRNA expression remained constant throughout the groups. Our data thus show that, following focal cerebral ischemia in hyperglycemic conditions, beta-actin is an unsuitable housekeeping gene whereas PBG-D is more appropriate. This study clearly demonstrates the importance of selecting a stable housekeeping gene when performing RT-PCR experiments.