Flowcytometric evaluation of the DNA distribution in isolated pancreatic islets from normal and diabetic mice

Pancreatic islets from C57BL/KsJ-db/db, and +/+ mice were isolated by collagenase. After isolation the islets were transferred to a hypotonic ethidiumbromide solution with 0.3% of the detergent Nonidet P40. After vortexing, the samples were analyzed in a BioPhysics Cytofluorograf 4802A. The DNA histograms were divided into 2c, 2-4c, 4c and 8c fractions under the assumption of a constant rate of DNA synthesis during the 2-4c phase. In comparison with normal mice, we found that diabetic mice had a lower fraction of 2c nuclei and a higher fraction of 2-4c, 4c, and 8c nuclei. These results obtained by flow cytometry are in agreement with results obtained by 3HTdR incorporation and by cytophotometry on histological sections.