Unilateral 6-OHDA lesion
The unilaterally 6-OHDA lesioned rat, the most popular and best
validated rodent model of Parkinson’s disease and LID
(Cenci et al. , 2018;
Duty et al. , 2011;
Schwarting et al. , 1996) was used.
One-hundred three (103) naïve rats (150 g) were unilaterally injected
under isoflurane anesthesia in the (right) medial forebrain bundle with
12 µg of 6-OHDA hydrobromide (dissolved in 0.02% ascorbate-saline),
according to the following stereotaxic coordinates from bregma and the
dural surface (in mm): antero-posterior (AP) -4.4, medio-lateral (ML)
1.2, dorso-ventral (DV) -7.8, tooth bar at -2.4 mm
(Paxinos et al. , 1986), as
previously described (Arcuri et al. ,
2018; Marti et al. , 2012;
Pisanò et al. , 2020). Animals were
pretreated with antibiotics (SynuloxTM, 50 µl/Kg,
i.p.), and the wound was sutured and infiltrated with 2% lidocaine
solution (EsteveTM). Two weeks later, rats were
screened by assessing the motor asymmetry score in two different
ethological tests (the bar and drag tests)
(Marti et al. , 2005). Rats showing
immobility time >20 sec at the contralateral paw in the bar
test, and <3 steps at the contralateral paw (or alternatively
a contralateral/ipsilateral paw ratio <50%) were used in the
study (Brugnoli et al. , 2020;
Pisanò et al. , 2020).