Cellular Proliferation, Preservation of Cardiac Tissue, and B Cell Localization After B Cell Injection Into Infarcted Myocardium
Animals were implanted with a 5-bromo-2'-deoxyuridine pellet at the time of infarction and cell injection for determination of cumulative cellular proliferation. After 2 weeks, animals were euthanized and hearts processed for assessment of 5-bromo-2'-deoxyuridine pellet incorporation into the nuclear DNA of proliferating cells of ligation plus saline-treated animals (A), or B cells cocultured with nonhematopoietic stem cells (B), B cell (C) and cultured B cell (D) injections. Positive cells were identified using antibodies directed against a 5-bromo-2'-deoxyuridine pellet. All nuclei were stained with hematoxylin. The percentage of cells staining positive for 5-bromo-2'-deoxyuridine pellet was determined by comparison with the total number of cells visualized in a minimum of 5 fields (200× magnification). Scale bars are 100 μm. Sham operated (no ligation, open squares, n = 5) and ligation plus saline injection (open circles, n = 6) animals were included as control animals (E). Solid circles represent animals injected with B cells (n = 10). B cells cultured overnight at 37°C (n = 10) are represented by solid squares, and B cells cocultured with nonhematopoietic stem cells cultured overnight at 37°C (n = 4) are represented by patterned squares. Each data point represents the percentage of 5-bromo-2'-deoxyuridine-positive cells counted in a single field, and the horizontal bar represents the mean ± SE. Significant differences in mean values between control and experimental groups are denoted by *p < 0.05 using the Student t test, 2-tailed.