Contralateral axon sprouting in male and female c57Bl/6J mouse cervical spinal cord by uninjured corticospinal axons following unilateral pyramidotomy and cortical injection of kinase inhibitors

STUDY PURPOSE: This study was designed to test whether a multitarget kinase inhibitor called SBP926, when microinjected into sensorimotor cortex of male and female c57Bl/6J mice at the time of injury, could promote sprouting of uninjured corticospinal tract axons into denervated contralateral cervical spinal cord after unilateral pyramidotomy. A related kinase inhibitor, RO48, was used as a comparison group, since we already had evidence that RO48 can promote sprouting in this assay. DATA COLLECTED: Data collected: There were 4 experimental groups, depending on the solution microinjected into the cortex from which the uninjured corticospinal tract arose. These were vehicle (DMSO) control, 1mM SBP926, 10mM SBP926, and 10mM RO48. In each case the volume injected into the cortex was a total of 2.5ul (500 nl at 5 locations: -1.0mm anterioposterior (AP) and +1.0mm lateral, -0.25mm AP and +1.0mm lateral, +0.5mm AP and +1.5mm lateral, +1.25mm AP and +1.5mm lateral, +2.0mm AP and +1.5mm lateral (all coordinates in reference to bregma), at a depth of 0.5mm below the surface of the brain), and AAV8 viral particles were co-injected into the cortex to label the sprouting axons. PKC-gamma staining of cervical spinal cord cross-sections was performed to confirm unilateral pyramidal tract section. The primary outcome measure for this dataset was “sprouting index”, which is a ratio of the density of labeled axon sprouts at 3 different distances from the midline in the contralateral cervical spinal cord to the number of labeled axons counted in the uninjured pyramidal tract at the level of the medulla. The number of labeled axons in the medulla was estimated by measuring the area of the medullary pyramid, then counting labeled axons in 5 constant area rectangles (“boxes”) randomly placed within the medullary pyramid area as a measure of average axon density. The axon sprout density in the spinal cord was estimated by counting intersections of labeled axons in cross-sections of the cord with each of 3 lines drawn dorso-ventrally in the parasagittal plane at 100, 400, and 700 um from the midline, respectively. The data were obtained from confocal images of histological sections taken at sacrifice, 5 weeks after surgery. The data are part of a larger study on RO48 and its derivatives. DATA USAGE NOTES: