Protective effects of DL­3­n­butylphthalide in the lipopolysaccharide­induced mouse model of Parkinson's disease.

DL­3­n­butylphthalide (NBP) is extracted from rapeseed and exhibits multiple neuroprotective effects, exerted by inhibiting the inflammatory process, including reducing oxidative stress, improving mitochondrial function and reducing neuronal apoptosis. The present study aimed to investigate the neuroprotective effects of NBP in a lipopolysaccharide (LPS)­induced mouse model of Parkinson's disease (PD). The behavior of mice was assessed using the rotarod test and open­field test, the amount of tyrosine hydroxylase in the substantia nigra pars compacta was evaluated by immunohistochemistry, and the levels of phosphorylated c­Jun N­terminal kinase (JNK), mitogen­activated protein kinase 14 (p38) and extracellular signal­regulated kinase 1 were determined by western blotting. It was demonstrated that the LPS­induced behavioral deficits were significantly improved. LPS­induced dopaminergic neurodegeneration was relieved following treatment with NBP, as determined from tyrosine hydroxylase­positive cells. Phosphorylation of JNK and p38 was significantly inhibited following treatment with NBP. Therefore in the present study, a role for NBP has been established in the treatment of a PD murine model, laying the experimental basis for the treatment of PD with this agent.

Therapeutic effects of paeonol on methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid-induced Parkinson's disease in mice.

Paeonol is a major phenolic compound of the Chinese herb, Cortex Moutan, and is known for its antioxidant, anti-inflammatory and antitumor properties. The present study was designed to investigate the therapeutic potential and underlying mechanisms of paeonol on a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid (MPTP/p)-induced mouse model of Parkinson's disease (PD). MPTP (25 mg/kg), followed by probenecid (250 mg/kg), was administered via i.p. injection for five consecutive days to induce the mouse model of PD. Paeonol (20 mg/kg) was administrated orally for 21 days. Behavior was assessed using the rotarod performance and open­field tests. Additionally, the levels of tyrosine hydroxylase (TH), microglia, interleukin­1ß (IL­1ß), and brain­derived neurotrophic factor (BDNF) in the substantia nigra pars compacta (SNpc) were evaluated by immunohistochemical staining. MPTP/p­induced motor deficits were observed to be significantly improved following long­term treatment with paeonol. Paeonol treatment decreased MPTP/p­induced oxidative stress, as determined by evaluating the activity levels of superoxide dismutase, catalase and glutathione. Additionally, MPTP/p­induced neuroinflammation was assessed by examining the levels of microglia and IL­1ß, which were significantly decreased following paeonol treatment. Paeonol treatment improved the MPTP/p­induced dopaminergic neurodegeneration, as measured by observing the increased TH level in the SNpc. Furthermore, the BDNF level was significantly elevated in the paeonol treatment group compared with mice treated with MPTP/p only. In conclusion, paeonol exerted therapeutic effects in the MPTP/p­induced mouse model of PD, possibly by decreasing the damage from oxidative stress and neuroinflammation, and by enhancing the neurotrophic effect on dopaminergic neurons. The results demonstrate paeonol as a potential novel treatment for PD.

Neuroprotective effects of piperine on the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson's disease mouse model.

Parkinson's disease (PD) is second only to Alzheimer's disease as the most common and debilitating age-associated neurodegenerative disorder. Currently, no therapy has been shown to unequivocally retard or arrest the progression of the disease. The aim of the present study was to investigate the protective effect of piperine on the 1-methyl-4-phenyl-1,2,3,6­tetrahydropyridine (MPTP)-induced Parkinson's mouse model. For MPTP treatment, the animals received repeated intraperitoneal injections (i.p.) of MPTP (30 mg/kg) solution for 7 days. Piperine (10 mg/kg) was administered orally for 15 days including 8 days of pretreatment. Motor behavior analysis was conducted with the rotarod test. The Morris water maze (MWM) was used to assess the cognitive learning ability of the mice. A histological examination was subsequently conducted. The results ddemonstrate that piperine treatment attenuated MPTP-induced deficits in motor coordination and cognitive functioning. Piperine also prevented MPTP-induced decreases in the number of tyrosine hydroxylase-positive cells in the substantia nigra. Additionally, piperine reduced the number of activated microglia, expression of cytokine IL-1ß, and oxidative stress following MPTP treatment. An anti-apoptotic property of piperine was identified by maintaining the balance of Bcl-2/Bax. In conclusion, the results show that piperine exerts a protective effect on dopaminergic neurons via antioxidant, anti-apoptotic, and anti-inflammatory mechanisms in an MPTP-induced mouse model of PD. Thus, piperine is a potential therapeutic treatment for PD.