Experimental Study On TGF-β₁ And Collagen Ⅰ,Ⅹ Gene Expression On Bone Healing Stimulated By Low-intensity Ultrasound

BACKGROUDFracture healing is a highly complex regenerative process that is essentially a reply of developmental events. These events include the action of many different cell types, a myriad of proteins, and active gene expression that in the majority of cases ultimately will restore the bone's natural integrity. Delayed union or nonunion will happen if this highly tuned process is slowed, interrupted, and even stopped. Low intensity ultrasound as a kind of non-invasive form of mechanical energy transmitted as high frequency acoustical pressure waves in biologic organisms can accelerate bone healing of fresh fracture and get good results in the treatment of delayed or non union. The Food and Drug Administration (FDA) approved the use of low-intensity ultrasound for the accelerated healing of fresh fractures in October 1994 and for the treatment of established nonunions in February 2000. On the basis of a broad spectrum of laboratory and clinical studies, several biological mechanisms have been proposed to explain the influence of ultrasound on the acceleration of the fracture repair process. Data suggest that ultrasound may induce conformational changes in the cell membrane and alter ionic permeability and second messenger activity. Changes in second messenger activity could then conceivably lead to downstream alterations in gene expression, resulting in an acceleration of the fracture repair process by upregulating cartilage and bone-specific genes as well as others. The mechanism of ultrasound interaction with the wound response may not be defined, it is clear that a host of cells, genes and other regulatory factors, many of may be influenced by the ultrasound signal, working together during the healing process.More and more about proteoglycan, cytokine, growth factor and collagen were known with the development of molecular biology and gene technique. There were no domestic experimental and clinical reports on accelerating effect of low intensive ultrasound on bone healing. No data on transforming growth factor beta and collagen changes after the stimulation by US were reported. With the study of these factors, we will understand the...