OBJECTIVETo evaluate the effect of orthodontic light force on the expression of Asporin, bone morphogenetic proteins-2 (BMP-2) and alkaline phosphatase (ALP) after auto-transplantation.

METHODSThirty-two maxillary and mandibular incisors in four 13 month-old male Beagle dogs were auto-transplanted to the other side of the same jaw. The teeth were all endodontically treated and divided into four groups, control (group 1) and three experimental groups (groups 2, 3 and 4).In control group, the teeth were unloaded. In the other three experimental groups, continuous force was applied in the 1st week (group 2), 2nd week (group 3) and 4th week (group 4) after auto-transplantation, respectively. The dogs were sacrificed in the 8th week. The mRNA expressions of Asporin,BMP-2 and ALP were examined by real time PCR. The expression of periodontal ligament associated protein-1 (PLAP-1) was examined by Western blotting. The data were statistically analyzed using SPSS 17.0 and one-way analysis of variance (ANOVA).

RESULTSIn group 3, the expression of Asporin mRNA (2.047 ± 0.281) was higher than that in the other three groups, while the expression of BMP-2 (1.358 ± 0.095) was lower than that in group 2 and control group (P < 0.05). The expression of PLAP-1 (1.054 ± 0.113) in group 3 was higher than other groups, while significant difference was found between any two groups.

CONCLUSIONSOrthodontic force could stimulate the expression of Asporin and PLAP-1. The orthodontic force applied in the 2nd week after the tooth auto-transplantation, the expression of Asporin and PLAP-1 reached the highest level.