Research Paper Volume 11, Issue 24 pp 12315—12327

β-arrestin2 alleviates L-dopa–induced dyskinesia via lower D1R activity in Parkinson’s rats

Figure 1. Recombinant adeno-associated virus (AAV)-induced β-arrestin2 overexpression (β-arrestin2+/+) in the unilateral 6-OHDA-lesioned striatum of SD rats. (A) Schedule of experiment in β-arrestin2+/+ rats. At the beginning of the studies, the rats (n=56) was injected unilaterally with 6-OHDA in the right medial forebrain bundle (MFB). After three weeks, lesion efficacy was assessed by the rotations after the use of apomorphine for the following induction of L-dopa-induced dyskinesia (LID). The β-arrestin2 overexpression rat models on the base of LID were constructed immediately and followed by intraperitoneal injection of D1R agonist (SKF38393) once a day. All groups of rats except PD and sham were injected with L-dopa (15 mg/kg, i.p.) plus benserazide (3.75 mg/kg, i.p.). Additionally, rats in the PD group and sham group were treated physiological saline. After the last drug administration, all rats were sacrificed in two hours and fetched the lesioned corpus striatum for the following WB, IHC and IFC. (B) Tyrosine hydroxylase (TH) protein levels was markedly decreased by nearly 90% in the PD or LID rats compared with sham group by western blot (n=4 for each group). (C) Fluorescence slice of coronal plane from striatum of rats between sham and PD groups stained with TH (n=4 for each group). Scale bar represents 100 um. (D) Still images showing L-dopa-induced dyskinesia in a parkinsonian rat. (E) AAV-β-arrestin2 expression (β-arrestin2+/+) relative to GAPDH level in five groups by WB in the lesioned striatum (n=4 for each group). The experiments for Figure 1B and Figure 1E were performed together with the same Sham, PD and LID tissues for western blot; (F) AAV-β-arrestin2 expression (β-arrestin2+/+) in five groups by IHC in the lesioned striatum (n=4 for each group). Scale bar represents 100 um. The experiments for Figure 1C and Figure 1F were performed together with the same Sham and PD for immunohistochemistry. @ P < 0.0001 vs sham group; * p < 0.05, ## P > 0.05 vs sham group; ***p<0.001 vs LID+EGFP group (n = 4 for each group, ANOVA followed by LSD post-hoc comparisons).