Lycium barbarum polysaccharide improves dopamine metabolism and symptoms in an MPTP-induced model of Parkinson’s disease

Abstract

Background Parkinson’s disease (PD) is the second most common neurodegenerative disease in middle-aged and elderly populations, whereas there is no cure for PD so far. Novel animal models and medications await development to elucidate the aetiology of PD and attenuate the symptoms, respectively. Methods A neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), was used in the current study to establish a PD pathologic model in silkworms. The time required to complete specific behaviours was recorded. Dopamine content was detected by ultra-performance liquid chromatography (UPLC). The activity of insect tyrosine hydroxylase (TH) was determined using a double-antibody sandwich method. Oxidative stress was assessed by changes in antioxidant enzyme activity and the content of oxidative products. Results MPTP-treated silkworms were characterized by impaired motor ability, reduced dopamine content, and elevated oxidative stress level. The expression of TH, a dopamine biosynthetic enzyme within dopaminergic neurons in the brain, was significantly reduced, indicating that dopaminergic neurons were damaged. Moreover, MPTP-induced motility impairment and reduced dopamine level in the silkworm PD model could be rescued after feeding a combination of levodopa (L-dopa [LD]) and carbidopa (CD). MPTP-induced oxidative damage was also alleviated, in ways consistent with other PD animal models. Interestingly, administration of Lycium barbarum polysaccharide (LBP) improved the motor ability, dopamine level, and TH activity, and the oxidative damage was concomitantly reduced in the silkworm PD model. Conclusions This study provides a promising animal model for elucidating the pathogenesis of PD, as well as a relevant preliminary drug screening (e.g., LBP) and evaluation.

A comprehensive review on the ethnobotany, phytochemistry, pharmacology and quality control of the genusLyciumin China

“…140 It was also declared that the administration of LBP could improve the motor ability, dopamine level, tyrosine hydroxylase (TH) activity as well as the reduction of oxidative damage in the silkworm PD model. 141 LBP also reduces abnormal protein accumulation through the AMPK-mTOR pathway and attenuates nigrostriatal mitochondrial damage in rats with PD, resulting in neuroprotective effects. 142 Lycium fruits could also regulate the function of the hypothalamic-pituitary-adrenal axis of depressed rats, and markedly reduce the serum cortisol content and expression level of the glutamate receptor in the hippocampus of rats, exerting its action of protecting hippocampal neurons and improving the behaviour of depressed rats.…”

“…140 It was also declared that the administration of LBP could improve the motor ability, dopamine level, tyrosine hydroxylase (TH) activity as well as the reduction of oxidative damage in the silkworm PD model. 141 LBP also reduces abnormal protein accumulation through the AMPK-mTOR pathway and attenuates nigrostriatal mitochondrial damage in rats with PD, resulting in neuroprotective effects. 142…”

Gastrodia elata polysaccharide alleviates Parkinson's disease via inhibiting apoptotic and inflammatory signaling pathways and modulating the gut microbiota

“…The accumulation of α-SYN in PD patients is higher than that in healthy individuals, and this phenomenon is also observed in MPTP-induced animal models such as monkey, mouse, and silkworm. [70][71][72] Aggregated α-SYN activated apoptotic pathways, inflammation, and other reactions, successively causing the death of DA neurons. 73 However, GEP improved the accumulation of α-SYN and the reduction of DA neurons in the SN and striatum of PD mice, at least preventing the loss of DA neurons during the development process of PD, thereby improving the motor ability.…”

Cold‐stored mulberry leaves affect antioxidant system and silk proteins of silkworm (Bombyx mori) larva

“…19 The silkworm model has been used to evaluate the effects of environmental pollutants, 20,21 heavy metals, 22,23 toxic chemicals, 24,25 pathogen infections 26,27 and new medicines. 28,29 Cold storage increases reactive oxygen species (ROS) in different fruit and vegetables. 30,31 Excessive ROS can be toxic to human cells, as they would destroy cell membranes, protein and DNA.…”

“…Therefore, many studies regarding assessment of human health are based on the silkworm model 19 . The silkworm model has been used to evaluate the effects of environmental pollutants, 20,21 heavy metals, 22,23 toxic chemicals, 24,25 pathogen infections 26,27 and new medicines 28,29 . Cold storage increases reactive oxygen species (ROS) in different fruit and vegetables 30,31 .…”