Netrin‐1 enhances coronary artery revascularization in the conotruncal‐banded chick embryo

Conotruncal (CT) banding in chick embryo caused severe restrictions in the proper development of the coronary artery. We utilize this model to hypothesize that netrin‐1 has an analogous function to endothelial growth factors thay would stimulate angiogenesis. Stage‐21 (3½‐d) chick embryo had a 10‐0 nylon suture tied around the conotruncus in an overhand knot. Netrin‐1 plasmid complexed with ABP (5 μg in 5 μl) was infused into the compact layer of the CT‐banded heart at stage‐29 (6‐d). Control groups included CT‐banded heart, and normal embryo that did not undergo conotruncal banding. At stage 36 (10‐d), India ink in PBS (1:5) was injected into the left ventricle and subsequently filled the coronary arteries. The heart was fixed in diastole with 4% paraformaldehyde and imaged under a stereophotomicroscope. Morphometric analysis was performed on the maximum coronary artery distance and ventricular vertical length. Data are presented as mean±SEM (n≥7), and analyzed by ANOVA. Coronary artery length indexed by ventricular length was similar between CT‐banding netrin‐1‐treated hearts (0.48±0.03, p>0.05) and normal embryos (0.50±0.02). This stands in contrast to a marked decrease in CT‐banded hearts (0.34±0.05, p<0.05) when compared to normal control. Coronary arteries in CT‐banded hearts with netrin‐1 treatment undergo proportionate vascularization and penetration comparable to normal control.