The effects of constraint-induced movement therapy on expression of tyrosine hydroxylase and glial cell derived neurotrophic factor in Parkinson's disease model rats

Abstract

Objective To explore the effects of constraint-induced movement therapy (CIMT) on the expression of tyrosine hydroxylase (TH) and glial cell derived neurotrophic factor (GDNF) in Parkinson's disease (PD) model rats. Methods PD models were established by microinjection of 6-hydroxydopamine (6-OHDA) solution into substantia nigra of rats' right cerebral hemisphere.Forty-two model rats were divided randomly into an exercise group and a control group 1 week after microinjection.The exercise group rats were forced to use their impaired limbs by placing their nonimpaired fore-limbs in casts.The control group rats were housed in the same environment without any special treatment.Two weeks after 6-OHDA infusion and exercise training,the behavioral changes of rats were examined after intraperitoneal injection apomorphine ( APO).The content of dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) was measured by high performance liquid chromatography with electrochemistry ( HPLAEC) ; the expressions of TH and GDNF in striatum were detected by immunohistochemical methods and TH,GDNF mRNA were detected by reverse transcription-polymerase chain reaction (RT-PCR). Results After 2 weeks of training,the rotating laps of the rats in exercise group within 30 min after APO induction,reduced to a significantly greater extent when compared to the control group (P ＜ 0.05).The content of DA and it's metabolites DOPAC in striatum homogenate was significantly higher in exercise group than that in the control group ( P ＜ 0.05 ),and the expression levels,of TH and GDNF protein/ mRNA were also significantly higher in the exercise group than those in control group ( P ＜ 0.05 ). Conclusions CIMT can improve the behavioral performance of PD rats,probably through promoting the expressions of TH and GDNF protein/mRNA in striatum,and increasing DA and it's metabolites DOPAC level. Key words: Constraint-induced movement therapy; Parkinson's disease; Dopamine; Tyrosine hydroxylase; Glial cell derived neurotrophic factor