Immunoblot analysis to detect phosphorylated MAPK proteins (p-JNK, p-p38, or p-ERK) in rat hepatic stellate cells exposed to MDA and/or acetaldehyde. Fifty μg of cell lysate were subjected to 10% SDS-PAGE and transblotted . Equal protein loading was based on Lowry protein assay and immunodetection of β-actin . Primary antibodies to phosphorylated kinases were diluted at 1:1000; secondary conjugate antibodies for enhanced chemiluminescence were diluted at 1:5000. The results shown represent of five separate studies. Lane 1: Cell exposure to both 200 μM MDA and 200 μM acetaldehyde (AC). Lane 2: Exposure to 200 μM MDA alone. Lane 3: Exposure to 200 μM AC alone. Lane 4: SF media only, control (C). Phosphorylated proteins were detected for all MAPKs examined. Only pJNK was significantly different under the experimental conditions compared to untreated, or control experiments. No significant difference appeared present between treatment groups. Time of exposure to aldehydes was 48 h.