Fig. 10

Summary of the surface area analysis of the pars compacta region of the substantia nigra for DAPI, tyrosine hydroxylase (TH), and α-synuclein (α-syn). (a) Image of a 40-μm nigral brain slice in the DMSO/Saline control group, with 3,3’-diaminobenzidine (DAB) and TH staining at 4 × magnification with a light microscope. (b) Representative images of DAPI (Blue), TH (Green, Alexa Fluor 555), and α-syn (Red, Alexa Fluor 647) staining in the substantia nigra pars compacta of rats with 7-day chronic intraperitoneal injections of the following agents: Control (DMSO/Saline), CPA, DPCPX + CPA, 1-aminoindan + CPA, and 2-aminoindan + CPA. CPA with or without 2-aminoindan increased α-syn immunofluorescence compared to control. The CPA-induced increase in α-syn was attenuated by DPCPX or 1-aminoindan. Scale bar, 20 μm. (c) Western blots from total lysates of the substantia nigra and quantification of α-syn level in the substantia nigra. CPA increased the level of 15 kDa α-syn monomers, which was attenuated by DPCPX and 1-aminoindan but not by 2-aminoindan. DPCPX and 1-aminoindan alone significantly reduced the level of 30 kDa α-syn dimers. In contrast, DPCPX, 2-aminoindan, and 1-aminoindan alone significantly increased the 75 kDa α-syn, which likely represent the α-syn tetramers. All values were normalized to β-tubulin III. n = 4 animals in each treatment group. Mean ± SEM. ns, non-significant; *P < 0.05; **P < 0.01; and ***P < 0.001 (one-way ANOVA followed by Student–Newman–Keuls post-hoc multiple comparison test)