The Depressive Behavior and Physiological Effects on CD-1 Female Mice (Mus musculus) Subjected to a Series of Chronic Unpredictable Stressors While on a High Flaxseed Oil Diet

Caitlin Verhalen, Department of Biology, York College

Introduction

Questions

Objective

Methods Results

Overall Conclusions

AcknowledgementsI would like to thank Dr. Rehnberg for his guidance and feedback throughout my research. I would also like to thank Joan Carpenter for supplying any necessary items needed for my research. Additionally I would like to thank Raphael Perez for his help in handling the animals and assisting with the behavioral tests.

Unpredictable chronic mild stress (UCMS) has been widely used in animals to mimic depression-like disorders. Damage from the UCMS such as oxidative stress is linked to many diseases like depression and anxiety (Kumar et al. 2011).

The adrenal glands are stimulated when the brain detects a stressful event and they release hormones like adrenaline and cortisol . There is a significant association between high cortisol levels and depression among individuals subjected to high stress (Kumar et al. 2010).

The failure to adapt successfully to stressful situations can result in stress-related diseases such as depression (Kumar et al. 2010).

The Omega-3s are polyunsaturated fatty acids (PUFAs) and those found in some plants contain alpha-linolenic acid (ALA) which has been associated with reducing depressive-like behavior. They can stimulate the communication between the nerve cells that are associated with emotional stability and positive emotions such as serotonin and dopamine (Tanna et al. 2013).

Flaxseeds are a rich source of Omega-3. Some PUFAs are known to reduce cortisol levels and affect the brain derived neurotrophic factor which aids in synaptic plasticity and protection of neurotransmitters (Tanna et al. 2013). The enhancement of neurotransmission helps to promote antidepressant effects.

1. Do popular claims about changing ones’ diet in

order to reduce depression hold true?

2. Would a diet with a higher quantity of essential

fatty acids, (EFA’s) like the rich source of Omega-3 in

flaxseeds be able to help reduce the cortisol/glucose

release as well as depressive behaviors in mammals?

To determine if a diet enriched with flaxseed oil will lower the effects of stress on CD-1 female mice as indicated by reduced behavioral depression and reduced levels of blood cortisol and glucose.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

C T F O N S T C O N S1 B C F O N B S C O F N

24 CD-1 Female Mice

GROUP I Vegetable

Oil Diet

GROUP IIFlaxseed Oil Diet

GROUP IIIVegetable

Oil Diet

Group IVFlaxseed Oil Diet

UCMS (22 Days)

Behavioral + Blood Tests on all

4 groups

A. Physiological results:

B. Behavioral results:

Figure 1. Set up for the forced swim test in 2000mL flasks with distilled H20

Figure 2. Set up for the tail suspension test in a 10 Liter glass tank separated by a cardboard division. Tails supported by tape hung from wooden rod on top of tank

Figure 3. Set up for the open field test. Field was surrounded by lamps on each side.

Week 1* Week 4* Difference*

Group I 22.9 25.2 2.3

Group II 21.9 27.64 3.2

Group III 24.2 28.3 3.1

Group IV 22.7 25.5 2.8

* Represents mean of all 6 mice per group

Table1. Mean weights (grams) for CD-1 mice

• Popular claims about introducing more flaxseed oil to ones’ diet to reduce depression are not supported.

• The change in diet for the CD-1 mice shows no significant implication that the increase of Omega-3’s in flaxseed oil would reduce physiological and most behavioral signs of depression.

• Behavioral signs of depression for the forced swim test varied significantly between groups suggesting that it may be the more adequate model for depression in mice compared to the other models tested.

References

Kumar, B., Kuhad., Chopra, K. 2011. Neuropsychopharmacological effect of sesamol In unpredictable chronic mild stress model of depression: behavioral and biochemical evidences. Psychopharmacology. 214: 819-828.Tanna, I., Pandya, P., Harisha, C.R., Shukla, V.J., Chandola, H.M. 2013. Pharmacognostical and Phytochemical evaluation of Atasi (Linum usitatissimum L.) Indian Journal of Traditional Knowledge. 12(4): 688-692.

n=6

C T F O N S B S1

Cage Tilt 14-18 hr.

T tail pinch 30sec

Water deprivation 24hr

Overnight illumination

No stress Cold Swim 12°; 5 min

Damp Bedding

Swimming room temp 23°; 10 min

A1. A2.

A3.

B1.

B2. B3.

Figure 1. Method for saturating pellets with oil. Future Studies

• Different administration route.• Biochemical analyses of stressed mice compared

to unstressed.• Do current antidepressant treatments fight

against this UCMS model.