Fig. 3

Immunofluorescence of primary NP cells and the effects of LTα on rat NP cell viability. (A) Immunofluorescence staining identified the rat primary NP cells. Red fluorescence: type II collagen-positive primary NP cells; blue fluorescence: DAPI-stained nuclei. The positive rate of NP cells was > 90%, and the purity of primary NP cells was > 90%. Scale bar: 50 μm. (B) Survival rate of rat NP cells that were treated or not with increasing concentrations of LTα for 72 h as determined by the MTT assay. (C) Survival rate of rat NP cells that treated or not with LTα (5 μg/ml) for various times as determined by the MTT assay. (D) LTα (5 μg/ml) and an equal volume of PBS were added to the experimental and control groups for 72 h, respectively, and the apoptosis rates of rat NP cells were determined by FCM. The apoptosis rate (Q2 + Q4) in the experimental group increased significantly (Q2: the late apoptotic stage; and Q4: the early apoptotic stage). (E) Statistical analysis of the apoptosis rate. ***, p < 0.001 (Unpaired, two-tailed Student’s t-test)