Willughbeia cochinchinensis ameliorates locomotor disorders in model of alzheimer’s disease mice

Objectives: To evaluate the effects of willughbela cochinchinessis (WC) to locomotor disorders in an Alzheimer''s disease (AD) model of mice. Subjects and methods: 50 Swiss mice were separated randomly into 5 experimental groups, 10 mice for each group.

WILLUGHBEIA COCHINCHINENSIS AMELIORATES

LOCOMOTOR DISORDERS IN MODEL OF

ALZHEIMER’S DISEASE MICE

Can Van Mao*; Tran Hai Anh*; Le Van Quan* SUMMARY

Objectives: To evaluate the effects of willughbela cochinchinessis (WC) to locomotor disorders in an Alzheimer's disease (AD) model of mice Subjects and methods: 50 Swiss mice were separated randomly into 5 experimental groups, 10 mice for each group Group 1: Mice were intraperitoneally injected (i.p) and orally administered (p.o) saline at dose 0.1 mL/10 g; group 2: mice were injected i.p scopolamin 1.5 mg/kg and p.o saline 0.1 mL/10 g; group 3, group 4 and group 5: mice were injected i.p scopolamine 1.5 mg/kg and p.o WC 100 mg/kg, 150 mg/kg and 200 mg/kg, respectively WC and saline were orally administered at 60 minutes and scopolamin and saline were injected i.p at 30 minutes before the behavioral task 60 minutes after WC injections, mice were placed in an open field for 5 minutes Behaviors of mice were observed by a camera and analyzed by Anymaze software Results: WC at doses 150 mg/kg and 200 mg/kg reversed scopolamin-induced hyperactivities in mice Conclusion: These results provided a basic for developing a new drug to treat patients with AD

* Keywords: Alzheimer's disease; Willughbela cochinchinessis; Scopolamin; Locomotor behaviors; Mice

INTRODUCTION

Alzheimer’s deasease is one form of

dementia in older humans Mechanism of

this kind disease has been suggested to

be involved in neurodegeneration and

formation of plaques and neurofibrillary

tangles [1] These changes in the brain

cause behavioral disorders such as

cognitive and memory impairments and

locomotor hyperactivities In patients with

AD, it has been shown that patients with

AD expressed hyperactivities in the late

afternoon and the evening These

hyperactivities are termed as sundown

syndrome or sundowing [2, 3] In animal

models of AD, previous studies have

been demonstrated that animals also exhibit increased locomotor activities including hyperactivity, stereotypic behaviors, and home cage activity disturbances [4]

It has been suggested that disorders of neurotransmitter systems, especially cholinergic system and glutamate systems are associated with abnormal behaviors

of patients with AD [5] Furthermore, abnormal activity of the cholinergic system affects glutamatergic systems [6] Thus,

it has developed a animal model of AD

by injecting intraperitoneally scopolamin,

a form of anticholiergic drug and used this model to study effects of new drugs

or natural plants in animal models of AD

* Military Medical University

Corresponding author: Cao Van Mao (caovanmao2011@gmail.com)

Date received: 15/06/2017 Date accepted: 10/08/2017

Recently, we applied this model to evaluate

effects of WC to scopolamin-induced

deficits in cognition and memory in mice

However, patients and scopolamin induced

animals with AD also showed disorders in

locomotion [2, 3, 7, 8] Thus, effects of

WC to locomotor disorders should be

evaluated We conducted the present study

with the aim: To investigate effects of WC

to ameliorate locomotor disorders in an

animal model of AD

SUBJECTS AND METHODS

1 Subjects

50 Swiss mice (150 - 250 g body weight)

were used in the present study Animals

were housed in individual cages, maintained

in controlled temperature and 12h light/dark

cycles with free access to water and food

The present study was conducted at

Department of Physiology, Vietnam Military

Medical University All procedures were

performed in accordance with the Animal

Center Guidelines for the Care and Use of

Laboratory Animals at the Vietnam Military

Medical University

2 Materials

WC was isolated by Department of

Pharmacy, Hochiminh City University of

Medicine and Pharmacy and was supplied

in power form WC power was dissolved

in saline using a magnetic stirrer

3 Methods

* Animal grouping and drug treatments:

Animals were separated randomly into

5 experimental groups, 10 mice for each

group: group 1 (control group): mice were ip

and p.o treated saline; group 2 (scopolamin

group): mice were i.p treated scopolamin

1.5 mg/kg and p.o treated saline at 0.1 mL/10 g; group 3, group 4 and group 5 (WC groups): mice were i.p injected scopolamin 1.5 mg/kg and p.o WC 100 mg/kg,

150 mg/kg and 200 mg/kg, respectively

WC and saline were orally administered

at 60 minutes and scopolamin and saline were i.p injected at 30 minutes before the behavioral task

* Open field test:

60 minutes after drug treatments, mice were placed in the center of a open field box Open field box was a square box (40 × 40 × 60 cm), covered with polypropylene sheets inside the wooden box (figure 1) Animals were allowed to free explore inside open field box for 5 minutes Behaviors of animals were recorded using

a digital video system Data was analyzed offline by ANY-maze software (Stoelting Co., Wood Dale, IL, USA)

Figure 1: Open field box

* Research indicators:

In the present study, we analyzed some research indicators as followed:

- Travel distances (m)

- Average speeds (m/s)

- Ratios of mobile time/immobile time

* Data analysis:

Travel distance, travel speed and ratio

of mobile time/immobile time were

analyzed by one-way analysis of variance (ANOVA) followed by the Tukey’s post-hoc test for multiple comparison, using SPSS 19.0 Results were considered to

be statistically significant at p < 0.05 All results were expressed as mean ± SEM

RESULTS

1 Changes in travel distance

Figure 2: Travel distance of mice

Figure 2 showed travel distance of mice in the open field test There was a significant difference in travel distance of mice in the experimental groups [F(5.49) = 3.82, p = 0.016] Post hoc test indicated that mean travel distance of mice in the scopolamin group was significantly longer than this in the control group (Tukey test, p < 0.05) After WC treatment, travel distance of mice decreased gradually from WC 100 mg/kg to WC 200 mg/kg However, a significant decrease in mean travel distance of mice was observed in only WC 200 mg/kg group (Tukey test, p < 0.05)

2 Changes in average speed

Figure 3: Average speed of mice

Figure 3 showed changes in average speed of mice in the open field test One way ANOVA indicated that there was a significant difference in average speed of mice in experimental groups [F(4.49) = 4.12, p = 0.011] Post hoc test indicated that there was

a significant increase in average speed of mice in scopolamin group, compared to this

in the control group (Tukey test, p < 0.05) After WC treatments, average speed also reduced gradually from WC 100 mg/kg to WC 200 mg/kg However, compared to average speed of mice in control group, a significant decrease in average speed was also observed in the WC 200 mg/kg group only (Tukey’s test, p < 0.05)

3 Changes in ratio of mobile time/immobile time

Figure 4: Ratio of mobile time/immobile time of mice

Figure 4 showed changes in ratio of

mobile time/immobile time of mice in the

experimental groups One way ANOVA

indicated that there was a significant

difference in ratio of mobile time/immobile

time of mice between experimental groups

[F(4.49) = 6.11, p = 0.01] Post hoc test

indicated that mean ratio of mobile

time/immobile time of mice in the

scopolamin group was significantly higher

than this in the control group (Tukey test,

p < 0.05) When mice were treated by WC,

these ratios decreased gradually Ratios

of mobile time/immobile time of mice in

WC 150 mg/kg group and WC 200 mg/kg

group were significantly lower than those

in the scopolamin group (Tukey test, p < 0.05)

Ratios of mobile time/immobile time of mice expressed mobile or immobile tendencies of animals If this ratio is higher than 1, it indicates that animals might tend to be mobile On the contrary,

it indicates that animals might tend to be immobile Results in figure 4 indicated that

WC at doses 150 mg/kg and 200 mg/kg reversed scopolamin induced increasing mobile tendencies of mice

DISCUSSION

Hyperactivity is one of behavioral disorders in both patients with AD and

animal models of AD In patients with AD,

it was demonstrated that they display

sleeping and locomotion disorders These

disorders are more serious in the late

afternoon and evening Thus, these disorders

were called as sundown syndrome or

sundowning [2, 3] Locomotor disorders

are observed in animal models of AD,

including the scopolamin-induced Alzheimer

model [7, 8] In these models, mice exhibit

hyperactivity tendencies during the dark

phase (the active phase of mice) [4]

Thus, in developments of new drugs or

natural plants to treat for AD, study on

locomotor functions of experimental animals

is necessary

Open field test used widely to investigate

locomotor functions in small animals such

as rats and mice This test allows to evaluate

many research indicators Thus, this test

will help us to study more particularly and

exactly the effects of new drugs to

locomotor functions of experimental

animals [9] In the present study, the open

field test was used to assess effects of WC

to scopolamine- induced hyperactivities of

animals with Alzheimer-like symptoms

Results showed changes in some

research indicators to indicate that WC

ameliorated disorders in locomotor

functions of animals These are: WC has

effects to decrease travel distance,

average speed and ratio of mobile

time/immobile time of animals with

scopolamin-induced hyperactivities These

results along with our previous study’s

results [6] provided a important basic to

apply new plants for treating AD in humans

CONCLUSION

In the present study, we used open field test to investigate effects of WC on scopolamin induced locomotor disorders

in animals with Alzheimer-like symptoms Our results indicated that WC at doses

150 mg/kg and 200 mg/kg reduced scoplamin-induced hyperactivities in experimental animals The reduction of hyperactivities was expressed by significant decreases in travel distance, average speed and ratio of mobile time/immobile timey These results provided important basic for next researches to use WC for treatment of AD in humans

ACKNOWLEDGEMENTS

This work was supported by Grant 106-YS.05-2013.24 from Vietnam’s National Foundation for Science and Technology Development (NAFOSTED)

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