Pancreatic Beta Cell Analysis in DJ-1 KO Mice

After four weeks of MLDS treatment, pancreata of wild type and DJ-1 KO mice were isolated and fixed in 4% paraformaldehyde for 24 h. Evenly spaced 10 μm sections were used to determine the beta cell area by staining them for insulin using the polyclonal guinea pig anti-Insulin antibody (DAKO). As secondary antibody we used goat anti-guinea pig conjugated with Alexa-Fluor-555 (Molecular Probes). DAPI (Sigma) was used to stain cell nuclei. Relative insulin-positive area was determined by quantification of the cross-sectional insulin-positive area divided by the cross-sectional area of the whole pancreatic section (nuclei area) and presented as percentage of control. Co-staining of DJ-1 and insulin in pancreatic sections was performed using rabbit anti-DJ-1 (1:100, [23 (link)]) and guinea pig anti-Insulin (1:300 dilution, DAKO).