Impact of nicotine on bone healing

A limited number of experimental animal studies and in vitro data confirm t hat nicotine impairs bone healing, diminishes osteoblast function, causes a utogenous bone graft morbidity, and decreases graft biomechanical propertie s. Therefore, our long-term goal is to develop an effective therapy to reve rse the adverse impact of nicotine from tobacco products. However, before a ccomplishing this goal, we had to develop an animal model: Our hypotheses w ere nicotine administration preceding:and following autoenous bone grafting adversely affected autograft incorporation and:depressed donor site healin g in a characterized animal wound model. Hypothesis testing was accomplishe d in bilateral, 4-mm diameter parietal bone defects prepared in 60 Long-Eva ns rats (male, 35-day-old). A 4-mm diameter disk of donor bone was removed from the left parietal bone and placed in the contralateral defect. The don or site served as a spontaneously healing bone wound. The rats were partiti oned equally among three doses of nicotine administered orally in the drink ing water (12.5, 25, and 50 mg/L). For each dose, the duration and sequence of nicotine treatment followed four courses, including no nicotine and des ignated combinations of nicotine administration and abatement prior to and- following osseous surgery. Experimental sites were recovered on 14 and 28 d ays postsurgery, responses quantitated, and data analyzed by analysis of va riance and post hoc statistics (p less than or equal to 0.05). We developed a convenient and effective osseous model, and the results validated our hy pothesis that nicotine negatively impacts on bone healing. (C) 1999 John Wi ley & Sons, Inc.