Functional Forelimb Recovery and Corticospinal Tract Changes after Chondroitinase Treatment in Male Primates after Cervical C7 Spinal Hemisection

STUDY PURPOSE: The purpose of the study was to evaluate the behavioral and neurobiological effects of intraparenchymal treatment with the enzyme chondroitinase (Chase) in rhesus monkeys that had undergone cervical (C7) spinal cord hemisection, targeting spinal cord circuits that control hand function. DATA COLLECTED: Fourteen (14) male Rhesus macaques, aged 6-10 years were assessed. Hand function was assessed using measures of open-field scoring of object manipulation, as well as the Brinkman board task to assess digital manipulation and fine motor skills. Five different boards of increasing difficulty were presented sequentially in each testing session. Difficulty was increased by: (1) increasing the depth of wells from which monkeys needed to extract the food reward; (2) altering the angle of the well relative to the monkey’s position; and (3) increasing the number of reward wells. Subjects were scored on the number of rewards obtained from each board, the time they took to clear the board and whether they used a pincer grasp. Tracing with biotin dextran amine and anterograde tracer dextran-conjugated AlexaFluor 440 was perfromed in order to measure corticospinal axon growth, and the number of synapses formed by corticospinal terminals in gray matter caudal to the lesion was also assessed (colocalization of BDA and synaptophysin). DATA USAGE NOTES: