Figure 1.

Proliferation and replicative stress of adult and infant BMSCs. (A) Human adult and infant BMSCs were isolated and analyzed using antibodies against CD29, CD44, CD73, CD90, and CD105 showed positive expression. Antibodies against CD11b, CD19, CD34, CD45, CD14, CD79a, and (HLA-DR) showed negative expression. Flow cytometry analysis was performed using the FACSCanto II Cytometer System, and isotype control staining was used as a control. (B) The fold increase in cell number was calculated based on the consistent seeding density of 1 × 10⁵ cells per dish, with passages conducted every 7 days. (C) The cell doubling time was computed for both adult and infant BMSCs across passages 2 (P2) to 9 (P9). The data presented here represent the mean ± standard error of the mean (SEM) calculated from three experimental replicates within both the infant and adult groups. Statistical significance between adult and infant BMSCs was determined using the Mann–Whitney U test. Statistical significance is indicated by *P < 0.05. (D) Phase contrast microscopy images of adult and infant BMSCs at passages 3 and 7 were captured at 40× magnification. The scale bar represents 200 μm. BMSC: bone marrow–derived mesenchymal stem cell. HLA-DR: human leukocyte antigen-DR.