6-OHDA Mouse Model
6-hydroxydopamine (6-OHDA) is a neurotoxin that is directly injected into the region of interest in the brain, usually the SNpc or striatum causing cellular dysfunction and death of DA neurons. The size of the lesion depends on the amount of 6-OHDA administered and is typically performed unilaterally. The advantage of unilateral lesions is twofold; the contralateral hemisphere serves as an internal control for each animal and lesion efficacy in individual animals can be estimated prior to sacrifice using certain behavioral tests.
Amphetamine rotation test: Amphetamine induced rotation test shows ca. 40% increase in ipsilateral rotations 3-6 weeks after the lesion, indicating the damage of nigro-striatal pathway in the 6-OHDA-injected (green), but not vehicle-injected (black) mice. Data presented as mean of n=4-8 with S.E.M., two-way ANOVA, with Tukey test, ****p<0.0001.
Striatal denervation: A) The photo depicts the tyrosine hydroxylase (TH) staining in coronal section of mouse brain, 6 weeks after the unilateral 6-OHDA lesion. The toxin injection evokes to 70-90% loss of TH-positive dopaminergic fibers in the striatum (vs. non-lesioned side). B) Data presented as mean of n=4-8, with S.E.M., two-way ANOVA with Tukey test, ****p<0.0001 (sham and 6-OHDA lesion groups within time point).
Neuronal loss in substantia nigra pars compacta: A) The images present the tyrosine hydroxylase (TH) staining in midbrain 3 weeks after the sham (above) or 6-OHDA (below) lesion. B) Stereological assessment of number of TH-positive dopaminergic neurons in substantia nigra pars compacta (SNpc) indicates a 50%-70% cell loss 3-6 weeks after the lesion. Data presented as mean of n=4-8, with S.E.M., two-way ANOVA, with Tukey test, ****p<0.0001 (sham and 6-OHDA lesion groups within time point), ##p<0.01 (6-OHDA groups).
Experimental End Points
- Behavioral Testing
- Quantification of DA neurons in the SNpc
- Quantification of DA terminals in the striatum
- Quantification of neuroinflammatory markers
- 3D-EM evaluation of mitochondrial and synaptic changes