Separation of radiolabelled protein from brain and spinal cord of spinal hemisected rats on SDS polyacrylamide slab gels.

After hemisection of the spinal cord in rats, alterations in amino acid incorporation into protein have been observed in brain and spinal cord. Proteins mediating these changes have been studied in the present experiment. Male, Long-Evans hooded rats were given either a laminectomy and dura incision (sham) at spinal segment T2, a left spinal cord hemisection, or no operative procedures. One hour prior to utilization at 1, 3 and 14 days postoperation, amimals were injected subcutaneously with 200 microCi of [3H]-L-lysine and 200 microCi of [3H]-L-amino acid mixture. Samples were prepared for electrophoresis and proteins separated on linear gradient SDS polyacrylamide slab gels (7.5-20% acrylamide). The Gel slabs were cut into slices and processed for scintillation counting. In right somatomotor cortex, there was evidence for a general stimulation of amino acid incorporation at one day postoperation in animals which received surgery. At other postoperation intervals, significant increases in proteins in the regions of 90-150,000, 50-65,000 and 35-45,000 molecular weight (MW) were observed. In spinal cord, significant increases in proteins in the regions of 55-65,000, 30-45,000 and 15,000 MW were observed over postoperation time in all animals receiving surgery compared to normals. A large, significant increase in the radioactivity of proteins in the region of 18-20,000 MW were observed in the spinal cord lesion site of spinal hemisected animals alone at three days postoperation. These results indicate that increases in amino acid incorporation into the brain and spinal cord of laminectomized and spinal hemisected animals observed previously are theresult of both specific and nonspecific changes in protein incorporation of precursors.