54. Nicotine Increases Osteoblast Activity in In Vitro Cell Culture in a Dose Dependent Manner
Scott Daffner MD1, John France MD1, Chad Smalley MD1, Stacey Waugh MS1, Timothy Norman PhD2, Suzanne Smith BS1, Nina Clovis1, Vincent Kish PT1 and Nilay Mukherjee PhD1
1West Virginia University, Morgantown, WV, USA
2Cedarville University, Cedarville, OH, USA

Available online 12 October 2009.

BACKGROUND CONTEXT: Prior studies by our group have shown that nicotine delivered via a transdermal nicotine patch significantly enhanced posterior spinal fusion rates in rabbits. This runs contrary to previously published studies by other groups in which nicotine administration decreased fusion rates. Hence, there may be a dose-dependent effect of nicotine on posterior spinal fusion outcomes.
PURPOSE: The purpose of this study was to determine if a dose-dependent relationship of nicotine and osteoblastic activity could be shown in an in vitro cell culture model.
STUDY DESIGN/SETTING: In vitro cell culture.
PATIENT SAMPLE: N/A.
OUTCOME MEASURES: Histologic assessment of osteoblastic activity and mineralization.
METHODS: A bone marrow derived osteoblast-like cell culture system was developed. Cells were exposed to one of six concentrations of nicotine: 20, 40, 80ng/ml and 10, 100, 250 g/ml. Control cells were not exposed to nicotine. Wells were stained with an alkaline phosphatase staining kit to determine the activity of the alkaline phosphatase enzyme. Cells were also stained with Von Kossa to determine mineralization.
RESULTS: A primary cell culture model of rabbit bone marrow derived osteoblast-like cells was established. A two-way ANOVA using dose and time as variables showed significant differences among groups (f=0.0021). A post hoc analysis (LS Means Differences Student t Test) among groups showed that the 100ug/ml dose of nicotine significantly enhanced alkaline phosphatase activity over controls. A one-way ANOVA using dose as the variable was performed and the 100 g/ml and 250 g/ml dose had significantly greater mineralization than controls. The dose response analysis revealed a statistically significant (p=0.001) effect of nicotine dose on alkaline phosphatase activity and Von Kossa activity at 4 weeks.
CONCLUSIONS: The beneficial effects of nicotine on spinal fusion could be, in part, due to the stimulation of osteoblastic activity. The effects of nicotine on spinal fusion are complex, may be dose dependent and may not always be detrimental. The uniformly negative effects of smoking reported on patients undergoing spinal fusion may possibly be attributed to the other components of cigarette smoke.
FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.