Prophylactic NAC intervention improved the quantity of BM ECs, CD34⁺cells, and their ROS levels in the EC < 0.1% group to levels similar to those in the EC ≥ 0.1% group post-HSCT. The dynamic reconstitution (left panel) and statistical analysis (right panel) of BM EC percentages (A), EC ROS levels (B), CD34⁺ cell percentages (C), and CD34⁺ cell ROS levels (D) were analyzed by flow cytometry in the EC < 0.1% with prophylactic NAC intervention group at −14 days and 0 days pre-HSCT and +1 month and +2 months post-HSCT relative to those in the EC ≥ 0.1% group in the second clinical trial. The data are expressed as the mean and SEM. Statistical analyses were performed using 1-way ANOVA for comparisons among the groups. Subject variables were compared using the χ² test for categorical variables and the Mann-Whitney U test for continuous variables. P < .05 was considered statistically significant and values are provided in the figure. *P < .05.