Meeting Abstract

P2.27  Tuesday, Jan. 5  Structure, Inflammation, and Repair in a Giant danio (Danio aequipinnatus) Model of Heart Injury LESCH, M.A.*; GRIVAS, J.A.; FROUNTFELTER, T.; GOLDEN, B.L.; FITZHARRIS, N.T.; NIDA, B.A.; LAFONTANT, P.J.; DePauw University; DePauw University; DePauw University; DePauw University; DePauw University; DePauw University; DePauw University pascallafontant@depauw.edu

The ultrastructural characteristics of the heart, the wound repair response and the ability to regenerate following injury were studied in the adult Giant danio (Danio aequipinnatus). The ventricular myocardium of the Giant danio displays a compact outer layer as well as a spongy inner layer typical of teleost hearts. Electron microscopy studies revealed myocyte ultrastructure and organization similar to that observed in the zebrafish (Danio rerio). Apical cauterization resulted in injury to 25% of the ventricle as assessed by a tetrazolium chloride assay. We observed a robust inflammatory response with early recruitment of heterophils and mast cells, and the persistence of inflammation past the second week post-injury. PCNA-positive cells were present adjacent to the site of injury over three weeks. Collagen accumulation was observed during the second and third week but had returned to baseline level at the end of the repair process by 45 days when the ventricle appeared completely regenerated. Our data suggest that like the zebrafish, the Giant danio possess robust repair mechanisms in the heart.