Fig. 3

β5i inhibition impairs antigen presentation in DA neuron. a The cytotoxic effect and chymotrypsin-like proteasome activity in the SN4741 cell line treated with PR-957 for 24 h were estimated by various methods such as DCFH-DA, rhodamine 123, CCK8 and CTL tests (n = 5 experiments). DCFH-DA, rhodamine 123 and CCK-8 were respectively used to measure ROS, the mitochondrial membrane potential and cell viability. A CTL assay was used to detect the chymotrypsin-like activity of cells. (b, c) Western blot analysis of TAP1 and Bip in SN4741 cells after treatment with 50 nM PR-957. Western blot analysis of TH, TAP1 and Bip in SN4741 cells 24 h after PR-957 treatment (d-f) and in PD model rats (g-i). CTL, chymotrypsin-like proteasome activity. N, normal group without treatment. C, control side of the rat brain. L, lesioned side of the rat brain. Data presented as the mean ± SD; n = 4 experiments; * P < 0.05, compared with the control; one-way ANOVA and post hoc SNK t-test