Differential effects of PGE ₂ versus minoxidil in FTOCs and RTOCs. (A) FTOCs were prepared with E13–13.5 embryos from the indicated genotypes of embryos. Individual paired thymic lobes were cultured in the absence or presence of increasing amounts of PGE₂ (100, 300, and 1,000 nM). The black colored symbols represent control (Tbx1^+/+;+/neo2) and red Tbx1^neo2/neo2 genotypes. After 10-day cultures, cells were harvested and enumerated. Cell viability was determined by flow cytometry with electronic gaiting. The percent of DP thymocytes was determined following CD4 and CD8 co-receptor staining followed by flow analysis. The number of mice used in each of the eight groups were n = 8, 5, 5, 5, 6, 5, 6, and 4, respectively. Statistical analyses were done with one-way ANOVA (Brown–Forsythe and Welch tests). Only statistically significant differences are presented. (B) FTOCs were established as in A in the presence of a single dose of minoxidil. After 10 days, the cellularity, cell viability, and percent of DP cells determined as in A. This was done with an n = 5, 6, 5, and 6 embryonic thymuses per group. (C) RTOCs were prepared using single-cell suspensions from thymic lobes isolated from either control Tbx1^+/+;+/neo2 or Tbx1^neo2/neo2-genotyped embryos. Identical numbers of cells (∼30,000) were cultured in media alone or that supplemented with 300 nM PGE₂. The number of experiments per group were n = 5, 6, 5, and 5. After 10 days, the total number of cells that grew was counted, and the cell viability and DP percentages were calculated following flow cytometry. Statistical analyses were done with one-way ANOVA (Brown–Forsythe and Welch tests).