Effect of the C-terminal chain of tetanus toxin on the motor behaviors in unilateral MPP+-lesioned rats

Abstract

Recently, the C-terminus fragment of the tetanus toxin (Hc-TeTx) has been shown to have neuroprotective effects against MPP+ and cytotoxicity. The aim of this study was to evaluate the effect of Hc-TeTx in MPP+- treated rats using motor behavioral tests and striatal survival. Male Wistar rats (250–300 g) were unilaterally injected with 2 μM of Hc-TeTx previous to MPP+ 1 μl (10 μg/μl) in left striatum, and another group were injected only with MPP+ in the same brain area. Then animals were assessed by turn behavior and skilled forelimb movements. Furthermore, the locomotor behavior and the forelimb use asymmetry were assessed. Finally, the viability of cells in the left and right striatum of the rat was examined by MTT assay. In rotational behavior task, Hc-TeTx/MPP+ group displayed a decreased number of ipsilateral turns (42.3%) with respect to the control group, and the locomotor behavior in close field was improved in 20%. The Hc-TeTx/MPP+ group had an improvement of 60% in the number of pellets reached using contralateral limb with respect to MPP+ animals in the staircase task. Indeed, forelimb use asymmetry of Hc-TeTx/MPP+ animals increased (44.7%) in both forelimbs use in the cylinder, and it was found that Hc mediated cell survival in the left striatum. The present study clearly shows that Hc-TeTx improves different motor behaviors and strongly favors the hypothesis of neuroprotective properties of Hc-TeTx fragment even in animals lesioned with MPP+.