miR-21 regulates the proliferation and apoptosis of astrocytes. Western blot and immunofluorescence of cells divided into two groups: one treated with PBS alone, and transfected with miR-21 OE or NC; and a second treated with TGF-β1 alone in combination with transfection of miR-21 KD or NC. (A) Bax, Bcl2, PCNA, caspase 3, cleaved caspase 3, and GAPDH were examined by western blot (n = 5). (B–G) Results were analyzed by ImageJ. (H) Ki-67 was examined with immunofluorescence. (I-J) The results of immunofluorescence were analyzed by imageJ and SPSS. Data are expressed as mean ± SD. *P < 0 .05, **P < 0.01, ***P < 0.001 compared with normal, TGF-β1, or NC group. Bcl2, B-cell lymphoma 2; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; miR, microRNA; miR-21 KD, LV-mmu-miR-21a-inhibition; miR-21 OE, LV-mmu-miR-21a; NC, negative control; PBS, phosphate-buffered saline; PCNA, proliferating cell nuclear antigen; SD, standard deviation; TGF-β1, transforming growth factor beta 1.