Hemisferectomia unilateral na vida adulta como modelo para o estudo das assimetrias motoras em camundongos

Abstract

A series of studies in humans have suggested that the planning and the control of movements are asymmetrically performed by the hemispheres. In general, lesions in the left hemisphere promote motor deficits that are more pronounced than similar lesions in the right hemisphere. In the present work, we used unilateral hemispherectomy to study the relative importance of each hemisphere in the control of movement in mice. Adult Swiss mice were submitted to right unilateral hemispherectomy (RH) or left unilateral hemispherectomy (LH) and sham surgery. Fifteen days after surgery, the motor coordination of each mouse was evaluated in the forced locomotion in rotating cylinder test (Rotarod). The latency to fall was significantly lower in right-hemispherectomized group as compared to control and did not differ from the left-hemispherectomized group. To help the interpretation of results obtained in the Rotarod test, a part of the sample was subjected to a additional battery of behavioral tests in the following sequence: open field test, qualitative assessment of sensory-motor asymmetry, foot fault test and tail suspension test. Interestingly, in the foot fault test, while the RH group showed significantly worse performance with the left hind limb (contralateral to the lesion) than with the right, the control group and the LH group showed no differences between both hind limbs. Similarly to what is observed in humans, our results suggest that the two hemispheres contribute asymmetrically to control of movement in mice.