Document Type : Original Article
DEPARTMENT OF PHYSIOLOGY, SHAHED UNIVERSITY, TEHRAN, IRAN
Introduction: Animal models of Parkinson’s disease (PD) with partial damage of nigrostriatal dopaminergic system are very suitable for development of treatment strategies. Although drug-induced rotational behavior has been conventionally used for analysis of lesioned animals, but bcause of the development of sensitization, it is necessary to invent a pure behavioral test that can evaluate such animals in a drug-free state which may better reflect a more natural response of the animal following lesion. This study was conducted to evaluate the efficiency of elevated-body swing test in analysis of unilaterally lesioned animals in an early model of Parkinson’s disease.
Material and Methods: Thirty male rats were randomly divided into sham-operated and lesion groups. An early model of PD was developed by interstitial injection of 12.2 microg of 6-hydroxydopamine (6-OHDA) into the left striatum. Apomorphine-induced rotational and drug-free elevated body swing behaviors were evaluated.
Results: Results of behavioral tests revealed that apomorphine caused a very significant contralateral turning in the rats of the lesion group (L+V) compared to sham-operated group (SH) (P<0.0001). In addition, there existed a significant difference between +V and SH groups in the second (P<0.01) and fourth weeks (P<0.05) after surgery. Further analysis of correlation for not number of rotations versus net number of rotations versus net number swings revealed a significant and positive correlation (r=0.52) in the second week in L+V group, but no such correlation was observed in the fourth week (r=0.24).
Conclusion: Taken together, it is concluded that elevated body swing test may be of less value in evaluation of motor asymmetry in an early model of Parkinson’s disease compared to drug-induced rotational behavior. Therefore, it may be used as a complementary test to drug-induced rotational test for alternate evaluation of motor asymmetry in unilateral model of early PD in rats.