Fig. 1. LPS induces degeneration of DA neurons and microglial activation in the SN in vivo. PBS (3 µl) or LPS (5 µg/3 µl) was unilaterally injected into the SN. At 7 d post-injection, the coronal sections (40 µm) were selected and processed for TH (A, B, E, F), NeuN (C, G) immunohistochemical staining or Nissl staining (D, H). (B, F) Higher magnifications of (A, E), respectively. (I) Stereological counting results of TH⁺ and Nissl⁺ neurons in the SN at 7 d post-injection. The SN tissues were immunostained with CD11b (J, K, P, Q), Iba-1 (L, M R, S), and CD68 (N, O, T, U) antibodies for microglia in the SN. (K, M, O, Q, S, U) Higher magnifications of (J, L, N, P, R, T), respectively. Dotted lines indicate SNpc where DA neurons were degenerated. Scale bars: A, E, 250 µm; B, F, 25 µm; C, D, G, H, 50 µm. J, L, N, P, R, T, 500 µm; K, M, O, Q, S, U, 50 µm. SNpc, substantia nigra pars compacta; SNr, substantia nigra reticulata. Data are presented as the means±SEM of four to seven animals per group. ^*p<0.001, significantly different from PBS (ANOVA and Bonferroni analyses).