Effects Of Electroacupuncture On The IRE1α-ASK1-JNk Pathway Of Endoplasmic Reticulum Stress In Rats With Parkinson’s Disease

Objective:Parkinson’s disease(PD),also known as tremor paralysis,is a kind of degenerative disease in the nervous system among the elderly population.It has a higher incidence and disability rate in the middle aged and elderly population,which is second only to Alzheimer’s disease,and is the second most common neurodegenerative diseasein the elderly.According to statistics,the total prevalence rate of PD in people over the age of 65 in China has reached 1700/10 million,and its prevalence will increase with age.According to foreign reports,PD in the incidence of 1 to 5 years of disability rate of 25%,while the incidence of more than ten years of disability rate of up to 80%.The clinical manifestations of PD is movement disorder,which including tremor,rigidity,bradykinesia and postural abnormalities.Early studies found that PD had two major pathological features,one is the degeneration and death of dopaminergic(DA)neurons in the substantia nigra pars compacta,the second is the formation of eosinophilic inclusion bodies-bodies Louis(Lewy,LB)in the cytoplasm of residual neurons.At present,the etiology and pathogenesis of PD are not fully understood,a large number of studies at home and abroad show that genetic,nervous system aging,environmental toxins,oxidative stress,mitochondrial dysfunction,excitatory toxicity,immune response,proteasome dysfunction,inflammatory response,and many other factors are involved in the occurrence of PD.In recent years,studies have shown that endoplasmic reticulum stress(ERS)is involved in the occurrence and development of stress,and may play a crucial role in the pathogenesis of PD.Our PD rat model was induced by a subcutaneous injection of rotenone at the rat’s nape.Rats in the EA groups were treated by EA at “ Fengfu ”(GV16)and “ Taichong ”(LR3).To explore the action mechanism of the IRE1 α-ASK1-JNK pathway mediated by endoplasmic reticulum stress(ERS)in rats with parkinson’s disease induced by rotenone and the effects of electroacupuncture on the pathway,in order to open up a new way of thinking for the acupuncture treatment of PD and provide a reliable experimental basis for clinical practice.Methods:120 Male SD rats were randomly divided into a normal group,a sham-operation group,a model group,a pretreatment group,four EA groups(Treatment respectively for 7 days,14 days,21 days,28 days),15 rats in each group.PD rat model was induced by a subcutaneous injection of rotenone at the rat’s nape,and rats in the sham-operation group were injected with sun-flower oil that did not include rotenone.Rats in the EA groups were treated by EA at “Fengfu”(GV16)and “Taichong”(LR3).While the normal group,sham-operation group and model group were not treated.Rats in the pretreatment group received the same treatment as the EA groups for 7 days and then established the model.After the treatment,open-field test and behavioral score was used to evaluate the ethology changes of PD rats.The positive expression of TH andα-syn in substantia nigra of rats were detected by immunohistochemical method.The expression of Bipm RNA、IRE1αm RNA、ASK1m RNA were tested by RT-PCR.And the expression of Bip、IRE1α、ASK1、p JNK protein in substantia nigra was tested by Western-blot method.Results:(1)Rats in model group showed obvious characteristics of PD syndrome.The behavioral score of PD rats after EA intervention was significantly improved compared with that in model group(P<0.01).(2)Compared with normal group and sham-operation group,the positive expression of α-syn in substantia nigra area significantly increased in model group(P<0.01);compared with model group,the positive expression of α-syn in substantia nigra area significantly decreased in EA groups and pretreatment group(all P<0.01).(3)Compared with normal group and sham-operation group,the positive expression of TH in substantia nigra significantly decreased in model group(all P<0.01);compared with model group,the positive expression of TH in substantia nigra of rats significantly increased in EA groups and pretreatment group(all P<0.01).(4)Compared with normal group and sham-operation group,the expression of Bipm RNA、IRE1αm RNA、ASK1m RNA in substantia nigra area significantly increased in model group(all P<0.01);Compared with model group,the expression of Bipm RNA、IRE1αm RNA、ASK1m RNA in substantia nigra area significantly decreased in EA group for 21 days and 28 days(all P<0.01).(5)Compared with normal group and sham-operation group,the Bip、IRE1α、ASK1 and p-JNK protein expressed in model group increased significantly(all P< 0.01);Compared with model group,the Bip、IRE1α、ASK1 and p-JNK protein expressed in EA groups and pretreatment group significantly decreased(all P<0.01).Conclusion:(1)Subcutaneous injection of rotenone can successfully construct PD rat model,this method is simple,economical,and has a high success rate.(2)Rotenone can induce α-syn accumulation in the substantia nigra,which would cause endoplasmic reticulum stress response.A long period of endoplasmic reticulum stress can induce degeneration of dopaminergic neurons,leading to the occurrence of Parkinson’s disease.(3)Electroacupuncture treatment can obviously improve the motor behavior of PD model rats,increase the number of TH positive neurons in the substantia nigra,reduce the aggregation of α-syn,and reduce the expression of endoplasmic reticulum stress related proteins.These results suggest that EA can regulate the endoplasmic reticulum stress response in PD rats,and play an important role in the protection of dopaminergic neurons.(4)The possible mechanism of electroacupuncture treatment of Parkinson’s disease is the electro acupuncture treatment can reduce aggregation of α-syn in substantia nigra,inhibition of endoplasmic reticulum stress in substantia nigra,protects dopaminergic neurons from degeneration and loss,thus delaying the occurrence and development of Parkinson’s disease.