(A) Number of cells after 0-, 48-, 96-, 144-, 192-, 240-, 288-, and 336-h culture in Hank’s balanced salt solution (HBSS) or Dulbecco’s modified Eagle’s medium (DMEM) with 0%, 1%, or 10% fetal bovine serum (FBS). Data are mean ± SD (n = 4). Two-way analysis of variance (ANOVA) with the Tukey-Kramer post-hoc test was used. *P < 0.05. **P < 0.01. (B) Dehydrogenase activity, DNA amount, and metabolic activity in cells after 48-h culture in HBSS or DMEM with 0%, 1%, 3%, 5%, 10%, or 20% FBS. Total dehydrogenase activity and DNA amount were assessed by the Cell Counting Kit-8 (CCK-8) and PicoGreen assay kit, respectively. Cell metabolic activity was calculated as dehydrogenase activity normalized to DNA amount. Data are mean ± SD expressed as the relative percentage of those in DMEM with 20% FBS (n = 4). Mixed-design ANOVA with the Tukey-Kramer post-hoc test was used. *P < 0.05. **P < 0.01. (C) Morphological cell appearance. Images shown are representative of four experiments with similar results (n = 4).