THE EFFECT OF THE PLATELET-DERIVED WOUND-HEALING FORMULA AND THE NERVE GROWTH-FACTOR ON THE EXPERIMENTALLY INJURED SPINAL-CORD

The main purpose of this study is to investigate the effect of platele t derived wound healing formula (PDWHF) and nerve growth factor (NGF) in the treatment of experimental spinal cord injury. PDWHF is a conglo merate of growth factors which include platelet derived growth factor (PDGF), platelet derived angiogenesis factor (PDAF), transforming grow th factor-beta (TGF beta) and platelet factor IV (PF4). Complete spina l cord transection was performed at T12 in rats and the treatment of t he spinal cord injury was achieved by filling the dead space with type 1 collagen gel impregnated with PDWHF, or with 2.5S-NGF. Controls wer e treated with only type 1 collagen gel. Animals were sacrificed at 1, 2 or 3 months. Histopathologically, tissue autolysis and cavity forma tion by phagocytosis expanded 1-3 mm into the cord stumps and the volu me of cavitation was less in the two treated groups. In the NGF group, a greater number of surviving nerve cells were observed in this regio n. Most of the control animals formed only thin, short axonal bundles, however, increased axonal regrowth was noted in animals treated with trophic factors, especially in the NGF group. The NGF group formed thi ck axonal bundles and abundant neuroma. Increased angiogenesis was obs erved in the collagen gel matrix and the injured spinal cord parenchym a, in the PDWHF group. Recent studies have shown that mammalian adult CNS possesses the ability for structural and/or functional plasticity following injury under appropriate circumstances. In this in vivo stud y, exogenous NGF appeared to induce axomal outgrowth and nerve cell su rvival. PDWHF produced notable angiogenesis which seemed to improve th e extracellular microenvironment. This may be important for the delive ry of exogenous trophic factors, nutrients and for the changes of extr acellular matrices to support nerve cells and axons.