Histomorphometric and Biochemical Evaluations of Stem Cells for Osteogenesis and Neogenesis

The purpose of this study was to quantify bone tissue and blood vessel area in the central part of regenerate after transplantation of Stem Cells From Human Exfoliated Deciduous teeth (SHED) in rabbit Mandibular Distraction Osteo Genesis (MDO) in comparison to conventional MDO, As well to measure serum Alkaline Phosphatase (ALP) level and to correlate the 3 parameters. A randomized controlled trial was carried out with 18, 3 - 5.5 month old male New Zealand white rabbits, weighing 2.8 ± 0.2 kg. All animals were divided into 2 groups with 9 animal each (A, as experimental group and B, control). Six million cells were transplanted into the distracted area during the osteotomy period. After a 4-days latency period, a total of 6 mm was distracted for 6 days. The newly formed bone in the central area of the DO regenerates were analyzed histologically, histomorphometrically and biochemically at weeks 2, 4, and 6 postoperatively. All data were analyzed using non parametric Mann-Whitney U test. Spearman correlation test was used to correlate between the 3 variables. The significance was accepted when P is less than 0.05. More bone was observed in the central area of SHED transplanted group histologically and Histomorphologically, the percentage of newly formed bone after 2 weeks were 16 and 0; after 4 weeks, 39 and 22; and after 6 weeks, 27 and 23% in the SHED and control groups respectively. The difference between the groups was statistically significant (P = 0.024). The calculated percentage of blood vessels area at 2 weeks SHED and control group were 5.9 and 4, at 4 weeks 34.42 and 14.64 and at 6 weeks 17.64 and 19% respectively, however; the difference between the groups was statistically not significant P = 0.489. The mean difference of serum alkaline phosphatase level of SHED and control groups were 128.33 and 42.66 respectively with significant result, p< 0.001. A positive correlation was found between the volume density of bone and blood vessels P = 0.014, volume density of bone and ALP, P = 0.029 and no correlation between blood vessel volume and ALP level, p = 0.372.