Effect of rat bone-marrow-derived mesenchymal stem cells(rMSC) on cranial bone healing

SUMMARYDifferent types of materials and chemicals have been used for the closure and accelerating thehealing of critical size cranial defects. In this study the effectiveness of the mesenchimal stem cells,which has avoked a curiosity recently, was investigated in critical size cranial defects of rats.Fifty wistar type male rats were evaluated in the study. Ten rats were used to obtain allogenicMSC?s. The remainders were separated into four groups. A full thickness circular bone defect 7 mm indiameter was created in the frontal bone of each rat. Group I (n=10) was operative control group. InGroup II demineralize bone matrix, in Group III mesenchimal stem cells and in Group IVdemineralize bone matrix and mesenchimal stem cell combination was applied into the defects. At theend of the 12th week, all of the rats were sacrificed. Radiologic evaluation of the defect areas within thegroups at zero, 4th, 8th and 12th weeks, bone density measurements and the healing pattern at the end ofthe 12th weeks were compared.In all groups there were statistically significant decrease in defect areas, but the average valuesof the defect areas within the groups were not statistically significant. The percentage of the healingarea of the Group III at the 12th week was statistically significant greater than Group I. Group III?sbone density at the 12 th week was the greatest but there was not a statistically significant differencewithin the groups for bone density. In Group III and Group IV, distrubuted healing patern wasobserved in 70% of the animals, on the other hand this healing patern was evident 40% of Group IIand 20% Group I. But there was not a statistically significant difference within the groups for healingpatern.In conclucion, allogenic rat mesenchimal stem cell application has created astatistically significant radiologic reduction at the bone defect area of the critical size cranialdefects at the end of the 12th week. Mesenchimal stem cell aplication has also increased thebone density and changed the healing patern. The positive effect on the healing of the defectarea was reduced while combined with demineralize bone matrix. The exact mechanism ofthis effect should be investigated in further studies.