Cambium cell stimulation from surgical release of the periosteum

An autograft of periosteal tissue containing cambium cells has potential to become chondrogenic or osteogenic depending on the regeneration repair strategies. The potential number of harvestable cambium cells diminishes with age. Other factors may be associated with a reduction in the number or variable yields of cambium cells including harvest technique, harvest site location, and the time interval from harvest to implantation. Attempts to increase the number of cambium cells have included improvements in harvesting and handling technique, and expansion of the cells in tissue culture. An "in situ" stimulation and proliferation technique would offer the potential for increasing the number of cambium cells in a cost-effective manner for transplantation without the need for expansion in tissue culture. The hypothesis tested was that surgical release of the periosteum and its deep inner underlying cambium layer by sharply incising through the superficial periosteal fibrous layer down to and scoring the cortical bone surface would increase the number of cambium cells that could be harvested at a later time period. Two techniques for periosteal release were used to stimulate a proliferation of the underlying cambium layer and increase the cambium cells for harvest in skeletally mature goats: (1) sharply scoring all four-sides of the tissue test site perimeter, and (2) sharply scoring only two sides of the tissue test site. The two-sided and four-sided release scoring of the periosteum induced stimulatory responses in the number of cambium cells. In addition, a marked increase in mRNA expression for BMP-2 (p<0.001) was observed within 24 h and remained elevated over baseline values for up to 96 h after this stimulation to the cambium layer.