An ultrastructural study of meconium corpuscles in human foetal colon.

In human foetal colon meconium corpuscles were observed in the colonic epithelium during the stage of secondary lumina development and enlargement. Transmission electron microscopy of these specimens revealed inclusion bodies in the superficial and deeper layers of the epithelium. Many of the membrane-bounded inclusion bodies contained well-preserved organelles and some inclusions contained nuclear fragments. There was evidence of nuclear fragmentation with condensed chromatin arranged in crescentic caps. The ultrastructural observations are typical of apoptosis, a mode of cell death first described in 1972 by Kerr and colleagues. Thus, meconium corpuscles are apoptotic bodies found as a result of the deletion of healthy normal cells during the reshaping and development of organs.