A Suggested Mechanism for Green Discoloration of the Postmortem Brain

Abstract

Abstract In the putrefied brain, the cortex and basal ganglia show dark-grayish to green discoloration due to sulfhemoglobin formed from hydrogen sulfide (H2S) produced by endogenous bacteria and hemoglobin. In this study, we propose and demonstrate another mechanism of green discoloration in the brain. The formalin-fixed brain of a cadaver donated for medical education with no putrefaction was used. Half of the brain was immersed in sodium hydrosulfide solution, to imitate the H2S produced by bacteria. This half showed greenish discoloration, mainly in the basal ganglia and cortex. The other half showed positive Perls' Prussian blue staining, mainly in the basal ganglia and cortex. The area of greenish discoloration due to H2S and the region positive for Perls' Prussian blue staining coincided. Tissue treatment with strong oxidizing agents is required to liberate heme iron. The positive Perls' Prussian blue staining in this study thus does not reflect heme iron. In conclusion, we considered that non–heme iron compounds physiologically present in the brain and H2S represent sources of putrefactive greenish discoloration in the brain.