The Experimental Research For Evaluating Mice's Dopaminergic Neurons Function By ^99mTc-TRODAT-1

Background: The main pathological characters of Parkinson disease (PD) are corpus striatum's dopamine agonist (DA) neuron degeneration and absence, which leads to decrease of DA and hyperfunction of cholinergic neuron.Some researchesIndicated that 1-methyl-4- phenyl- 1 , 2 ,3 ,6- tetrahy dropyridine (MPTP) had the effect of neuron poison and injurd dopaminergic neurons; Ginsenosi deRg1 may have protection effect of DA neuron. DA neuron dopamine transporter (DAT) plays an important role in information transformation. ^99mTc- TRODAT-1 maybe have value in evaluating MPTP's injury and ginsenside Rg1's protection effect for DA neuron.Objective: To investigate whether the tracer, ^99mTc- TRODAT-1has the value of evaluating MPTP's injury and ginsenside Rg1's protection effect for DA neuron by observing the corpus-striatum /cerebellum ratios in C₅₇BL₆-mice's brain.Methods: Divide 27 C₅₇BL₆-mice in to 3 groups in random, 9 mice per group. MPTP group that 0.1 normal saline solution were injected to abdominal cavity, last 3 days, on the 4th day 30mg/kg MPTP were injected, last 5 days; Rg1+MPTP group that hypodermic injection with 5mg/kg Rg1 ,last 3 days; on the 4th day, first hypodermic injection with Rg1, then injected to abdominal cavity with 30mg/kg MPTP, last 5 days; Control group that injected to abdominal cavity with 0.1ml normal saline solution, last 8 days. The behavior change was observe of mice during 2h postinjection on the 1st, the 3rd and the 5th day. On the 9th day. Two C₅₇BL₆ mice of each group in random were proceed immunohistochemistry to observe the quantity change of tyrosine hydroxylase positive cells in sunbstantia nigra compact zone. the rest 7 mice aftrer 3h postinjection of ^99mTc-TRODAT-1( 5.5MBq/0.5ml), were executed for measuring weigh and radioactive count of calculate striatum /cerebellum ratios.Results:1. The change of mice behavior15 min postinjection of MPTP, all the mice in MPTP group and Rg1+MPTP group showed symptom of thrilling, pilo-erection, and raising tail in different degree. Three times postinjection of MPTP, the mice showed the symptom of light stagger, activity decrease, slow act, and bad concordance. Five times postinjection of MPTP, the symptom of the mice in MPTP group increased obviously; on the contrary, the symptom of the mice in Rg1+MPTP group increased lightly; Control group did not show the above behavior change.2. The quantity of TH immunity positive neuron:The quantity of TH immunity positive neuron in MPTP group is the least, is 59.0 and 53.2 separately; the quantity of TH immunity positive neuron in Rg1+MPTP group increased, is 71.6 and 64.6; the quantity of TH immunity positive neuron in control group is the most, is 94.0 and 88.6.3. Striatum /cerebellum ratiosThe median of striatum /cerebellum ratios in MPTP group is 0.73 (0.52-2.19), the median of striatum /cerebellum ratios in Rg1+MPTP group is 0.94(0.90-3.58); the median of striatum /cerebellum ratios in control group is 1.56 (1.09-4.27).These is obvious statistic difference between the MPTP group and the normal group(P<0.05),however, there is no difference between the MPTP group and Rg1+MPTP group, nor is between the Rg1+MPTP group and the control group. (P=0.09,0.20. P>0.05)Conclusions:1. MPTP induces C₅₇BL₆ mice to be injured of dopamine neuron.2. ^99mTc-TRODAT-1 has value in evaluating the injury of C₅₇BL₆ mice dopamine neuron.3. ^99mTc-TRODAT-1 may have value in evaluation that Ginsenside Rg1maybe have protection effect of the dopamine neuron injury caused by MPTP, but still needs farther research.