Fig. 3. DACA alleviates motor dysfunction and protects dopamine neurons in mice. (A) Schematic representation of the protocol used for MPTP and DACA treatments. (B-C) Behavior test analysis. Open filed test and pole test were recorded and analyzed (n =12 per group). (D-E) Immunofluorescence analysis of dopamine neurons in brain SN tissue. Scale bar 100 mm. Data are shown as representative pictures(D) and mean fluorescence intensity(E) (n = 5 per group). (F-G) Immunofluorescence analysis of dopamine neurons in striatum tissue. Scale bar 1000 mm. Data are shown as representative pictures(F) and mean fluorescence intensity(G) (n = 5 per group). (H-I) Immunoblot analysis of tyrosine hydroxylase (TH) in midbrain tissue. Data are shown as representative pictures (H) and quantified relative expression (I) (n = 5 per group). (J-K) Immunoblot analysis of tyrosine hydroxylase (TH) in striatum tissue. Data are shown as representative pictures (J) and quantified relative expression (K) (n = 5 per group). Data shown are mean ± SEM;#p < 0.05, ##p < 0.01 vs. control; *p < 0.05, **p < 0.01 vs. MPP+. NS. not significant.
3.3 DACA protected dopaminergic neurons by preserving the TH level in the substantia nigra(SN) and striatum
The expression of tyrosine hydroxylase (TH), a critical regulator involved in the maintenance and regulation of midbrain neurons, is found to be reduced in patients with PD. Immunofluorescence and Western blot were used to detect the changes of TH levels in the brain of mice to explore the therapeutic effect of DACA. Immunofluorescence labeling of TH showed that MPTP provokes a marked degeneration of dopaminergic neurons in the SNc and dopaminergic fibers in the Str, which was largely prevented by DACA (Fig. 3D-G). Meanwhile, western blot analysis revealed that DACA significantly attenuate the MPTP-induced decrease of TH levels in the midbrain and striatum (Fig. 3H-K). These results suggest that DACA protects against MPTP-triggered dopamine neurodegeneration in the SN and striatum.