Fig. 4. Apoptotic effects of TMZ, MSC-IFN-β, or both in combination. The PBS group was used as a control. A : Apoptotic cells were detected by TUNEL staining in cryosections. TUNEL-positive nuclei (red) were stained and counterstaining was conducted with DAPI (blue). Magnification, ×200. B : The TUNEL staining intensity was quantified by computerized image analysis. The results are representative of two independent experiments (n=5 in each groups). Columns, mean; bars, SEM. ^*p<0.05; Student's t-test. TMZ : temozolomide, MSC-IFN-β : MSCs to secret mouse IFN-β, PBS : phosphate-buffered saline, SEM : standard error of the mean, TUNEL : terminal deoxynucleotidyltransferased UTP nick end labeling, DAPI : 4,6-diamidino-2-phenylindole.