Intracardiac injection of matrigel induces stem cell recruitment and improves cardiac functions in a rat myocardial infarction model.

Matrigel promotes angiogenesis in the myocardium from ischemic injury and prevents remodelling of the left ventricle. We assessed the therapeutic efficacy of intracardiac matrigel injection and matrigel-mediated stem cell homing in a rat myocardial infarction (MI) model. Following MI, matrigel (250 mu l) or phosphate-buffered solution (PBS) was delivered by intracardiac injection. Compared to the MI control group (MI-PBS), matrigel significantly improved left ventricular function (n = 11, P < 0.05) assessed by pressure-volume loops after 4 weeks. There is no significant difference in infarct size between MI-matrigel (MI-M; 21.48 +/- 1.49%, n = 10) and MI-PBS hearts (20.98 +/- 1.25%, n = 10). The infarct wall thickness of left ventricle is significantly higher (P < 0.01) in MI-M (0.72 +/- 0.02 mm, n = 10) compared with MI-PBS (0.62 +/- 0.02 mm, n = 10). MI-M hearts exhibited higher capillary density (border 130.8 +/- 4.7 versus 115.4 +/- 6.0, P < 0.05; vessels per high-power field [HPF; 400x], n = 6) than MI-PBS hearts. c-Kit+ stem cells (38.3 +/- 5.3 versus 25.7 +/- 1.5 c-Kit+ cells per HPF [630x], n = 5, P < 0.05) and CD34+ cells (13.0 +/- 1.51 versus 5.6 +/- 0.68 CD34+ cells per HPF [630x], n = 5, P < 0.01) were significantly more numerous in MI-M than in MI-PBS in the infarcted hearts (n = 5, P < 0.05). Intracardiac matrigel injection restores myocardial functions following MI, which may attribute to the improved recruitment of CD34+ and c-Kit+ stem cells.