(A) Folds of the metabolic activities of pre‐osteoblasts within 5 days after a short (2 h) treatment with either no Hst1, no ATRA (control), or 10 µm Hst1, or 10 µm ATRA, or co‐administered 10 µm ATRA and 10 µm Hst1 with α‐MEM containing 10% FBS during seeding (n = 6). (B) Folds of DNA content at 0 day and 5 days after response graph of DNA content after a short (2 h) treatment with either no Hst1, no ATRA (control), or 10 µm Hst1, or 10 µm ATRA, or co‐administered 10 µm ATRA and 10 µm Hst1 with α‐MEM containing 10% FBS during seeding (n = 6). (C) Folds of ALP activity at 3 days after a short (2 h) treatment either without Hst1 or ATRA (control), or with 10 µm Hst1, or 10 µm ATRA, or co‐administered 10 µm ATRA and 10 µm Hst1 with α‐MEM containing 2% FBS during seeding (n = 8). Data were plotted using graphpad prism (GraphPad Software version 6.0) analyzed by one‐way ANOVA with Bonferroni's post hoc test for multiple comparisons. Data were shown as mean ± SD. *P < 0.05; **P < 0.01; ***P < 0.001.