Effects of sustained delivery of IGF-1 in a rat degenerative disc model

Degenerative disc disease is a leading source of pain as well as increased health care costs in the United States, and research efforts into understanding the pathophysiology of this disease are necessary for the development of new management strategies. Addition of growth factors to stimulate chondrocyte development are on the horizon as new treatment modalities for degenerative disc disease, but increasing growth factor concentrations in the body may have adverse affects on vital organs. The objective of this study was to investigate the use of sustained delivery of insulin-like growth factor-1 (IGF-1) for treatment of degenerative discs using the adult male rat as a model. The results showed increased chondrocyte proliferation and decreased apoptosis at the traumatized disc after 28 days. Analysis of the vital organs revealed slight increases in kidney wet weights, and closer histomorphometric evaluation of the tissue revealed changes in the proximal tubules. Further investigation to evaluate the potential physiological or pathophysioloigcal effects of the growth factors at the organ levels is warranted before use as therapeutic agent to treat degenerative disc disease.