Expression of NCAM-140 in mice substantia nigra during dopaminergic neuron cells damage.

Objective:In orderto detect the expression of RET in the mesencephalic substantia nigra(SN) and explore the possible roles during the dopaminergic(DA) neuron cells damage.Methods:We divided C57BL/6 mice into three groups:MPTP group, NS group and Control group and used MPTP(i.p)to establish DA neuron cells chronic injury model.We set six time points :the first week to the sixth week (1w-6w)and tested the mice behavioral changes after MPTP injection.Then we applied the methods of immunofluorescence and western blotting to detect the expression of tyrosine hydroxylase (TH) and RET in the mice SN.Results:The behavioral results showed that the scores of the suspension test decreased from the third week compared to the NS group(P0.05).In the step-down test, the time of the mice jumpped onto the platform extended gradually and the errors were increased gradually after elctric shock.The immunofluorescence double-labeled results showed that RET positive cells were obviously presence in mice substantia nigra at all of the time points and co-expressed with TH in the same neurons.Western blotting showed that TH protein began to decrease from the third week after MPTP injection and RET kept high expression from the first week to the second week but decreased from the third week.Conclusions:This expression suggest that the expression of RET was associated with the DA neurons damage.