EFFECTS OF RECOMBINANT BASIC FIBROBLAST-GROWTH-FACTOR, INSULIN-LIKE GROWTH-FACTOR-II AND TRANSFORMING GROWTH FACTOR-BETA(1) ON DOG DENTAL-PULP CELLS IN-VIVO

The effects of recombinant basic fibroblast growth factor (bFGF), insu lin-like growth factor (IGF)-II and transforming growth factor (TGF)-b eta(1) on dental pulp cells were investigated by light and transmissio n electron microscopy after their implantation for 1 and 3 weeks at ce ntral sites of mechanically exposed pulps in dog molar and canine teet h. The implants were Millipore filters that have been soaked with solu tions containing 100 or 500 ng/ml of bFGF or IGF-II or 100 ng/ml of TG F-beta 1. Control filters were soaked with dog albumin. No changes in cell organization or matrix synthesis were seen after implantation of control filters. Groups of columnar, polarized cells with numerous mit ochondria and Golgi elements or elongated cells unassociated with any matrix deposition were demonstrated after 1 or 3 weeks, respectively, in close proximity to the filters that had been soaked with bFGF solut ion; at a distance from these implants enhanced formation of an osteot ypic matrix was seen beneath the exposure site. No particular response was found in close proximity to the filters that had been soaked with IGF-TI solution after 1 or 3 weeks implantation but thick zones of os teodentine were found beneath the exposure site and at adjacent circum ferential dentine sites. Numerous elongated, polarized cells with long cytoplasmic extensions invading the filter pores were consistently se en after 1 week in close proximity to the filters that had been soaked with TGF-BI solution. After 3 weeks implantation of these filters, de position of a tubular matrix surrounding the implants was seen in asso ciation with the highly elongated odontoblast-like cells, while enhanc ement of circumferential dentine formation was also found at adjacent peripheral sites. These experiments demonstrate that TGF-BI when impla nted for short term periods at central pulp sites exerted dentine-spec ific effects, inducing differentiation of odontoblast-like cells and s timulating primary odontoblasts. Implantation of bFGF and IGF-II did n ot result in reparative dentine formation, but did stimulate osteotypi cal matrix deposition at a distance from the implants. (C) 1998 Publis hed by Elsevier Science Ltd. All rights reserved.