A07
Age‐related increase of tau protein and modifications of egr‐1 transcription factor in the canine brain

Abstract

INTRODUCTIONThe term canine cognitive dysfunction syndrome (CCDS) is used in veterinary literature to describe the progressive neurodegenerative disorder of senior dogs that is characterized by a gradual decline in cognitive function [1,2]. Currently a diagnosis of cognitive impairment is based on identifying the clinical symptoms by collecting owner's opinions and observations. Although neuropsychological testing is certainly a better measure of cognitive impairment than owner assessment, most of the pet dogs are periodically controlled by veterinary practitioners that are not specialists of behaviour. Since this condition does not allow the use of complex procedures, availability to practitioners of a battery of easy and short protocols to measure the cognitive impairment is advisable. In the present work we have developed a battery of tests (open field, curiosity test and reversal learning) for assessment of cognitive decline in pet dogs. MATERIALS AND METHODSIn the open field test, various locomotion indices were recorded in a 3 · 3 m testing room for a fixed time (3 min). The curiosity test allows the dog to examine and play with a variety of toys to assess the animal's reaction to novel objects or exploratory behaviour. In the reversal learning test, the animal must discriminate between two positions to obtain a food reward: once the dog learns which position is correct, the food reward is switched to the previously unrewarded position and the animal must then inhibit its learned behaviour. RESULTSThe results of the open field test indicate no significant difference in locomotor activity (P < 0.05, Student t-test for unpaired data) between a group of young-middle aged pet dogs (2-9 years) and a group of aged pet dogs (over 10 years). Similar results were obtained in the curiosity test. Conversely, the performance of the two groups was significantly different both during the acquisition and the reversal session of the reversal learning test. Aged dogs took more time than young-middle aged dogs to discriminate between two positions to obtain a food reward (267 ± 9.4 s versus 227 ± 14 s; P < 0.05, Student t-test for unpaired data) or to inhibit their previous learned behaviour (255 ± 13 s versus 135 ± 15 s; P < 0.05, Student t-test for unpaired data). Finally, from our data, a linear relationship and a significant correlation between chronological age (independent variable) and the progressive impairment of cognitive performance (dependent variable) in both sessions of the reversal learning have been obtained (acquisition: y = 8.02x + 178; r = 0.732, P < 0.05) (reversal: y = 17x + 51.5; r = 0.856, P < 0.05). DISCUSSIONOur protocols, together with the accurate anamnesis and the specific geriatric examination, could be valuable and effective tools to formulate a diagnosis of cognitive impairment in aged pet dogs. REFERENCES 1.