Fig. 2

Tyrosine hydroxylase (TH) immunostaining in rat SNc after in vitro rotenone (ROT) (b) rotenone + H₂O₂ (c), rotenone + H₂O₂ + rasagiline (RAS) (d) and rotenone + H₂O₂ + SZV558 treatment (e). The caudal part of the brain containing the SNc was prepared from rats and then the experiment was continued according to the protocol described in the Methods. After the experiment, 40 μm coronal vibratomic midbrain sections were prepared and processed for TH immunostaining. a Immuno-DAB staining for TH on control tissue sections. Immunoreactivity is seen in the cell body and processes of dopaminergic and noradrenergic neurons. b Due to rotenone treatment both the number of immunolabelled neurons and the intensity of staining is substantially decreased. The cell bodies of stained neurons are smaller than in the control sample. c Weak immunostaining shows some TH-expressing neurons on the rotenone + H₂O₂treated section. d TH immunoreactivity in SNc after rotenone + H₂O₂ + rasagiline treatment. e Intensity of DAB immunostaining for TH on the SN area looks similar to the control tissue after rotenone + H₂O₂ + SZV558 treatment of the tissue. Arrows show cell body of dopaminergic/noradrenergic neurons. Original magnification: 20X, bar: 100 μm f. Quantification of the TH immunostaining. Digitalization was performed by means of a Pannoramic P250 scanner (3DHISTECH, Budapest, Hungary) using 9 optical layer with a resolution of 0.11 μm/pixel. Pictures were taken at five representative areas in each of samples at 40× magnifications. The stained cells were counted manually, marked with a marker counter function of the Pannoramic Viewer 1.15.4 digital slide viewer software application provided by 3DHISTECH, Budapest, Hungary and expressed as number/mm² (nr/mm²). Statistical analysis: one-way ANOVA followed by the Tukey test. **P < 0.01, ***P < 0.001, as indicated by the horizontal bars. N = 4–5 /group