Impact Of Anxiety Pretreatment On Acute Mice Model Of Parkinson's Disease

Objective: Parkinson's disease(PD) is a common neurodegenerative disorder with elderly. The clinical manifestations of PD are movement disorders such as rest tremor, rigidity, bradykinesia, postural reflex disturbance. In addition, non-motor features such as depression, anxiety,constipation, sleep abnormalities, cognitive impairments also common in PD.Among these, anxiety is a factor in determining health-related quality of life,progression of disability, and prognosis of PD patients. But so far, very few people know that the effects of incident that can lead people to develop anxiety pretreatment about PD patients. Therefore, C57BL/6 mice was used to establish three kinds models: anxiety pretreatment groups, acute PD groups and anxiety pretreatment acute PD groups, aiming to explore the effects of anxiety pretreatment on emotion, motor, learning and memory, dopaminergic neurons in acute PD model mice.Methods:68 healthy male mice in 13weeks(23~30g) were randomly divided into the following 4 groups(n=17):(1) Control groups(CON groups): normal mice without any treatment;(2) Anxiety groups(ANX groups): using modified vogel water conflict(VCT) and restraint stress pretreatment made anxiety pretreatment model mice;(3) Acute PD groups(PD groups): mice intraperitoneal injection MPTP to made acute PD model mice;(4) Anxiety pretreatment acute PD groups(ANX+PD groups): given MPTP drugs as PD groups after given stimulus as ANX groups.Each group was feed in the same environment. After anxiety pretreatment 5, 6, 7 and 8-13 days, we examined the behavioral changes respectively using the elevated plus maze(EPM), the open field test(OF),the pole test(PT) and the morris water maze(MWM) to measure the behaviors and biochemical influences on the numbers of tyrosine hydroxylase positive(TH+) neurons after anxiety pretreatment 14 days.Result:1. The effects of anxiety pretreatment to mice1.1 The effects of anxiety pretreatment to mice on emotion EPM was carried out 1day after anxiety pretreatment. In comparison to the CON groups, there was a significant decrease in the percentage entries of open arm entries(OE%) and the percentage time spent on open arms(OT%) in ANX groups(P<0.05).OF was carried out in 5 days after anxiety pretreatment. In comparison to the CON groups, there was no significant difference in the percentage of center journey, center time, center squares crossed and total squares crossed in ANX groups(P>0.05).EPM was carried out again in 6 days after anxiety pretreatment. In comparison to the CON groups, there was no significant difference in the OE% and the OT% in ANX groups(P>0.05).1.2 The effects of anxiety pretreatment to mice on motor PT was carried out after anxiety pretreatment 7 days. In comparison to the CON groups, there was no significant difference in the time in ANX groups(P>0.05).1.3 The effects of anxiety pretreatment to mice on learning and memory MWM was carried out within anxiety pretreatment 8-13 days. The results showed that the latency to reach the platform was gradually shortened with four groups within the five days. In comparison to the CON groups, there was a significant decreased in the latency in ANX groups(P<0.05). In the spatial searching test, in comparison to the CON groups,there was no significant difference in the journey, the time and the crossed platform times that the mice stayed in the platform quadrant in ANX groups(P>0.05).1.4 The effects of anxiety pretreatment on the numbers of TH+ neurons in substantia nigra(SN) and striatum1.4.1 The numbers of TH+ neurons in SN The TH+ neurons in SN were arranged compact, neat, plump nucleus,clear nucleolus in CON groups and ANX groups. In comparison to CON groups, there was no significant difference in the numbers of TH+ neurons in ANX groups(P>0.05).1.4.2 The mean optical density(MOD) of TH+ neurons on striatu In comparison to CON groups, there was a significant reduce in the MOD in ANX groups(P<0.05).2The effects of MPTP to mice2.1 The effects of MPTP to mice on emotion EPM was carried out 1 day before MPTP injection. In comparison to CON groups, there was no significant difference in the OE% and the OT%in PD groups.OF was carried out 3 days after MPTP injection. In comparison to CON groups and ANX groups, the percentage of center journey, center time,center squares crossed had no significantly difference(P>0.05), but total squares crossed was significantly increased in PD groups(P<0.05).EPM was carried out 4 days after MPTP injection. In comparison to CON groups and ANX groups, the OE % and OT % had no significance difference in PD groups(P>0.05).2.2 The effects of MPTP to mice on motor Mice appeared tremor, arch, vertical tail and hair, hind legs, gait instability, shortness of breath within a few minutes after injection of MPTP,and with the increase of drug delivery times, its behavior appeared more and more faster. These symptoms often ease in half an hour, almost recovered after 24 h.PT was carried out 5 days after MPTP injection. In comparison to CON groups and ANX groups, the climbing pole time was no significant difference in PD groups(P>0.05).2.3 The effects of MPTP to mice on learning and memory MWM was carried out within 8 to 13 days after MPTP injection. In comparison to CON groups and ANX groups, the latency was significantly prolong(P<0.05) and the time, journey and crossed the platform were significantly decreased in PD groups(P<0.05).2.4 The effects of MPTP on the numbers of TH+ neurons in SN and striatum2.4.1 The numbers of TH+ neurons in SN TH immunohistochemical staining was carried out 12 days after MPTP injection. The TH+ neurons were residual shrivel, not full, fusiform,protuberant in PD groups and every 200 times magnification the numbers of TH+ neurons got down 49.70% that compared with CON groups. In comparison to CON group and ANX group, TH+ neurons for PD group were significantly reduced(P<0.05).2.4.2 The MOD of TH+ neurons in striatum In comparison to CON groups and ANX groups, there was a significant reduce in the MOD in PD groups(P<0.05).3. The effects of anxiety pretreatment to acute PD model mice3.1 The effects of anxiety pretreatment to acute PD model mice on emotion EPM was carried out one day after anxiety pretreatment. In comparison to CON groups and PD groups, the OE% and the OT% were significantly decreased in ANX+PD groups(P<0.05). In comparison to ANX groups, the OE % and OT % were no significance difference in PD groups(P > 0.05).OF was carried out in 5 days after anxiety pretreatment. In comparison to CON groups, ANX groups and PD groups, there was no significance difference in the percentage of center journey, center time, center squares crossed in ANX+PD groups(P>0.05). In comparison to CON groups and ANX groups, the total squares crossed had no significant difference in ANX+PD groups(P>0.05). In comparison to PD groups, the total squares crossed were significantly reduced in ANX+PD groups(P<0.05).EPM was carried out again in 6 days after anxiety pretreatment. In comparison to CON groups, ANX groups and PD groups, the OE % and OT % had no significance difference in ANX+PD groups(P>0.05).3.2 The effects of anxiety pretreatment to acute PD model mice on motor PT was carried out after anxiety pretreatment 5 days. In comparison to CON groups, ANX groups and PD groups, the climbing time were significantly increased in ANX+PD groups(P<0.05).3.3 The effects of anxiety pretreatment to acute PD model mice on learning and memory MWM was carried out within anxiety pretreatment 8-13 days. In comparison to CON groups and ANX groups, the latency had a significantly prolong in ANX+PD groups(P<0.05). In comparison to PD groups, there was no significant difference of the latency in ANX + PD groups(P>0.05).In comparison to CON groups and ANX groups, the movement distance,residence time and numbers of crossed the platform were significantly decreased in ANX + PD groups(P<0.05). In comparison to PD groups, the movement distance, the residence time and the numbers of crossed the platform all had no significant difference in ANX+PD groups(P>0.05).3.4 The effects of anxiety pretreatment to acute PD model mice on the numbers of TH+ neurons in SN and striatum3.4.1 The numbers of TH+ neurons in SN TH immunohistochemical staining was carried out 14 days after anxiety pretreatment. It was showed that the TH + neurons in SN were residual shrivel, not full, fusiform, protuberant in ANX+PD groups and every 200 times magnification the numbers of TH+ neurons got down to49.40% compared with CON groups. In comparison to CON groups and ANX groups, the numbers of TH+ neurons were significantly reduced in ANX+PD groups(P<0.05). In comparison to PD groups, the numbers of TH+ neurons was no significant difference in ANX+PD groups(P>0.05).3.4.2 The MOD of TH+ neurons in striatum In comparison to CON groups and ANX groups, there was a significant reduce in the MOD in ANX+PD groups(P<0.05). In comparison to PD groups, there was a certain degree decreased but no significant reduce in the MOD in ANX+PD groups(P>0.05).Conclusion:1 Anxiety pretreatment can lead mice have obvious anxiety, but maintain shorter; improve the learning ability and reduces the dopaminergic nerve fibers in striatum, but had no obvious effect on motor function,memory ability and dopamine neurons in SN.2 MPTP impaired motor function when mice injection and as time goes on motor function gradually recovery, basic returned to normal within 24 h,obviously reduce the learning and memory ability, serious damage the dopaminergic neurons in SN and nerve fibers in striatum, but had no influence on mice emotion.3 Anxiety pretreatment obviously aggravate motor function damage,significantly increase the learning with acute PD model mice, but had no obviously influence on the emotion, memory ability and dopamine neurons within SN and striatum.