Purpose: Parkinson's disease (PD) is associated with the destruction of dopaminergic neurons in the substantia nigra (SN). Hydroxychloroquine (HCQ) has the capability to cross the blood-brain barrier and promote a neuroprotective potential. This study evaluated the effects of HCQ on the 6-hydroxydopamine (6-OHDA)-induced PD model in rats.
Methods: Wistar rats were randomly divided into sham, PD, PD + levodopa and PD + HCQ groups. The PD model was induced by a stereotactic administration of 6-OHDA into the left SN pars compacta (SNpc) and confirmed by rotation and the Murprogo's tests. HCQ (100 mg/kg, p.o.) and levodopa (12 mg/kg, p.o.) were administered once a day for 21 days. Three weeks after surgery, the behavioral tests were performed. Brain lipid peroxidation index (MDA), glutathione peroxidase activity (GPx), total antioxidant capacity (TAC) levels and α-synuclein protein expression in the SN were also measured.
Results: The behavioral tests demonstrated that induction of PD increased the muscle rigidity and the number of rotations, which were reversed by HCQ treatment. Also, induction of PD was associated with an increase in α-synuclein protein levels and MDA and decreased TAC levels and GPx activity. However, HCQ decreased α-synuclein and MDA levels while increased TAC levels and GPx activity. In addition, histopathological data showed that HCQ protects dopaminergic neurons against 6-OHDA-induced toxicity.
Conclusion: According to the results, HCQ has a beneficial effect in improving PD-related pathophysiology, in part, by mitigating oxidative stress and protecting the dopaminergic neurons in the SN.
Keywords: 6-OHDA; Parkinson’s disease; hydroxychloroquine; levodopa; oxidative stress.