Effects of Dietary Food Ingredients on Recognition Memory by using Object Recognition Test in Mice

Kadiri Sunil Kumar¹*, CH. Mamatha², N. Deepika², B. Sai Sushma², R. Suthakaran³

¹Associate Professor, Department of Pharmacology, Vijaya College of Pharmacy, Munaganoor- 501511, Hyderabad, Telangana, India

²B-Pharmacy Final Year II Sem, Vijaya College of Pharmacy, Munaganoor- 501511, Hyderabad, Telangana, India

³Professor and Principal, Department of Pharmaceutical Chemistry, Vijaya College of Pharmacy,

Munaganoor- 501511, Hyderabad, Telangana, India

*Corresponding Author E-mail: sunil.cology@gmail.com

ABSTRACT:

The present research was designed to compare the effects of dietary food ingredients such as saccharin (100 mg/kg), turmeric (1g/kg) and transfat (2%) on recognition memory in albino mice by using object recognition test (ORT) apparatus. The mice were divided into 5 groups, each group containing 6 mice. The test group of mice received treatment of saccharin (100mg/kg), turmeric (1g/kg), transfat (2%), donepezil (1mg/kg) for 30 days. Control group mice received distilled water for 30 days. The evaluation of memory begins on 31^st day by using object recognition test. The ORT apparatus is composed of open box (16x5cm) with an open roof. The object recognition test includes 3 sessions A) The first day training session which consist of placing all the mice one by one in an empty recognition chamber for 5 minutes so that the mice get habituated in the environment (habituation). B) On second day, test session begins (acquisition) where in the control mice are allowed to explore 2 different objects of same size, color and weight but with different shapes for period of 5 minutes (FandF1) and the time taken by each mouse to explore the objects (mouse touches its nose or places its nose at a distance of 2 cm from the object) was recorded. Repeat the same procedure with test (saccharin (100 mg/kg), turmeric 1g/kg and transfat 2%) and standard donepezil (1mg/kg) treated mice. The Third day session includes exploring the control, test and standard treated mice to one familiar object (F) and a new object (N) for a period of 5 minutes. Discrimination index which is an index of memory is calculated in all the groups of mice. Discrimination index (DI) was found to be 0.0714± 0.17 in control mice, whereas DI was found to be 0.015±0.12 and 0.027±0.09 with saccharin and transfat. Turmeric treated mice exhibited a DI of 0.25±0.09. The above readings indicate the DI of saccharin and transfat treated mice found to be less than control mice indicating memory impairment with saccharin and transfat. However, turmeric treated mice exhibited increased DI than control indicating memory enhancement with turmeric. Standard Donepezil treated mice exhibited significant higher DI (0.37±0.72).

KEYWORDS: Recognition memory, dietary ingredients, donepezil, discrimination index, object recognition test.

INTRODUCTION:

The process of recovering information about past events or knowledge is called as Memory¹In psychology, memory is the process in which information is encoded, stored and retrieved². Cognition is the mental ability of developing knowledge and understanding through thought, experience and the senses³. Poor memory, slow recall and lower retention are common problems in today’s world⁴. Memory declines mostly under stress and fatigue⁵. There are reports in the literature that certain ingredients in our regular diet such as saccharin and transfat have deteriorating effects on memory whereas ingredient like turmeric has memory enhancing effect. Hence the present study was planned with an objective to compare the effects of the above mentioned dietary ingredients on memory using a widely accepted novel nootropic evaluation model such as object recognition test in albino mice.

MATERIALS AND METHODS:

For the present study, the dietary food ingredients such as turmeric and transfat were collected from local super market. Saccharin (sodium saccharin) was procured from Sd-fine chemicals ltd., Mumbai. Standard drug donepezil was obtained as a gift sample from microlabs, Bengaluru. The doses of saccharin (100 mg/kg), turmeric (1 g/kg), transfat (2%) and donepezil (1 mg/kg) used for the present study were selected from the literature. Stock solutions of saccharin and donepezil were prepared in distilled water, whereas the stock solutions of transfat and turmeric were prepared in 1% acacia suspension.

Experimental animals:

Albino mice (20-25g) were used for the nootropic evaluation. They were procured form Sainath agencies, Musheerabad, Hyderabad (282/99/CPCSEA). After randomization into various groups and before initiation of experiment, the rats were acclimatized for a period of 10 days. Animals were housed in polypropylene cages and maintained under standard environmental conditions such as temperature (26±2°C), relative humidity (45-55%) and 12 hr. dark/light cycle. The animals were fed with mice/rodent pellet diet (Golden Mohur Lipton India Ltd) and water ad libtum. The study protocol was approved from the Institutional Animal Ethics Committee (IAEC) before commencement of experiment (1292/ac/09/CPCSEA).

Effects of saccharin, turmeric and transfat on memory by Object recognition test in mice:

The experiment was performed on albino mice (20-25 g) of either sex procured from sainath agencies, musheerabad. The animals were housed in colony cages at an ambient temperature of 26+2⁰C and, relative humidity (45-55%) with a 12h/12h light dark cycle and access to food and water ad libitum. Food was restricted during experiments. Divide the animals in to 5 groups i.e control group, saccharin (100 mg/kg) , transfat (2%) , turmeric (1 g/kg) treated test groups and standard donepezil (1 mg/kg) treated group, each group consisting of six mice. The control, test and standard groups were treated with the above mentioned ingredients and donepezil for 30 days. On 31^st day one hour after the treatment, all the animals were subjected to object recognition apparatus assessment of nootropic levels. The apparatus is composed of open box (16x5cms) with an open roof. Two similar objects of same size, color, weight but with different shapes were placed at opposite corners in the box. The object recognition test includes 3 trials: The first day training session in which each mouse is placed for 5 min to acclimate the manipulations and environment for decreasing stress (habituation). After training trail, second day test session begins (acquisition), where in the control mice are allowed to explore 2 different objects (FandF1) of same size, weight and color but with different shapes for period of 5 minutes and the time taken by mouse to explore the objects (mouse touches its nose or places its nose at a distance of 2 cm from the object) was recorded. Repeat the same procedure with saccharin (100 mg/kg), transfat (2%), turmeric (1 g/kg) and standard donepezil (1 mg/kg) treated groups after 1 hr of administration of saccharin, transfat, turmeric and donepezil. The 3rd day session includes exploring the control mice to one familiar object (F) and a new object (N) for a period of 5 minutes. Repeat the same procedure with saccharin (100 mg/kg), trans fat (2%) , turmeric (1 g/kg) and standard donepezil (1 mg/kg) treated groups after 1 hr of administration of saccharin, transfat, turmeric and donepezil and the same exploration procedure was repeated (NandF) for control, test and standard treated mice. Discrimination index was calculated as N-F/N+F

Figures 1-6: Object Recognition Test in mice

Fig: 1: Different objects used in ORT

Fig: 2: Habituation

Fig: 3: Mouse exploring F object

Fig: 4: Mouse exploring F1 object

Fig: 5: Mouse exploring F object

Fig: 6: Mouse exploring N object

STATISTICAL ANALYSIS:

The values are represented as mean ± S.E.M and statistical significance between treated and control groups was analyzed using One way ANOVA, followed by Dunnett’s test where P<0.001, P<0.01 and P<0.05 was considered statistically significant.

RESULTS AND DISCUSSION:

The mice were treated with dietary ingredients such as saccharin, transfat and turmeric for a period of 30 days and on 31^st day object recognition test which is the most widely used in vivo model for the assessment of memory was used to evaluate spatial working memory in mice. In object recognition test discrimination index is used as a factor for the assessment of memory. Discrimination index is determined in all the groups of rats. Discrimination index (DI) was found to be 0.0714± 0.17 in control mice, whereas discrimination index was found to be 0.015±0.12 and 0.027±0.09 with saccharin and transfat. Turmeric treated mice exhibited a discrimination index of 0.25±0.09. The above findings indicate that the discrimination index of saccharin and transfat treated mice found to be less than control mice indicating memory destruction with saccharin and transfat. However, turmeric treated mice exhibited increased discrimination index than control indicating memory improvement with turmeric.

Table 1: Discrimination Index with Control, Saccharin, Transfat, Turmeric and donepezil treated mice

Group	Discrimination Index
Control	0.0714±0.17
Saccharin (100 mg/kg)	0.015±0.24^*
Turmeric (1 g/kg)	0.25±0.09^**
Transfat (2%)	0.027±0.18^*
Donepezil (1 mg/kg)	0.37±0.72^**

Values are expresses in Mean± SEM and statistical significance between treated and control groups was analyzed using one way ANOVA, followed by Dunnets test where ^**P<0.01 and ^*P<0.05 were considered statically significant.

Fig: 7: Graphical representation of effect on dietary food ingredients on discrimination index (DI) using object recognition test in mice

CONCLUSION:

By performing the above research, we conclude that certain dietary food ingredients like saccharin and transfat has a memory deteriorating effect found in mice whereas turmeric is found to have memory enhancing potential evaluated by object recognition test in mice. Further neurochemical analysis and histopathology of brain tissues are required to establish the exact mechanism behind the nootropic potential of turmeric and amnesic effect of dietary food ingredients.

ACKNOWLEDGEMENTS:

The authors are grateful to the management of Vijaya College of Pharmacy, Hyderabad for providing the facilities for our research.

REFERENCES:

1. Hyde, T. S., and Jenkins, J. J. (1969). Differential effects of incidental tasks on the organization of recall of a list of highly associated words. Journal of Experimental Psychology, 82, 472-481.

2. Baddeley, A. D. (1966). "The influence of acoustic and semantic similarity on long-term memory for word sequences". Quart. J. Exp. Psychol 18 (4): 302–9.

3. Parke, R. D., and Gauvain, M. (2009). Child psychology: A contemporary viewpoint (7th Ed.). Boston, MA: McGraw-Hill.

4. Atkins CM, Selcher JC, Petraitis JJ, Trzaskos JM, Sweatt JD 1998. The MAPK cascade is required for mammalian associative learning. Nat Neurosci 1:602–609.

5. Petkov VD, Yonkov D, Mosharoff A, Kambourova T, Petkov VV, and Todorov I. 1986. Effects of alcohol aqueous extract from Rhodiola rosea L. roots on learning and memory. Acta Physiol Pharmacol Bulg 12(1):3–16.