Standard loading controls are not reliable for Western blot quantification across brain development or in pathological conditions

A frequently utilized method of data quantification in Western blot analysis is comparison of the protein of interest with a house keeping gene or control protein. Commonly used proteins include beta-actin, glyceraldehyde 3 phosphate dehydrogenase (GAPDH), and beta-tubulin. Various reliability issues have been raised when using this technique for data analysis-particularly when investigating protein expression changes during development and in disease states. In this study, we have demonstrated that beta-actin, GAPDH, and beta-tubulin are not appropriate controls in the study of development and hypoxic-ischemic induced damage in the piglet brain. We have also shown that using an in-house pooled standard, loaded on all blots is a reliable method for controlling interassay variability and data normalization in protein expression analysis.