[Expression and distribution of SDF-1 in the soft tissue healing of tooth extraction]

To observe the expression and distribution of stromal cell derived factor -l (SDF-1) in the soft tissues after tooth extraction, in order to provide new ideas to promote wound healing of tooth extraction.

Thirty male Wistar rats were randomly divided into 10 groups. After extracting the first molar of left mandibular respectively, immunohistochemistry and RT-PCR technique were used to evaluate the distribution and expression of SDF-1 1, 2, 4, 7 and 10 days after extraction. Data processing was performed using SPSS 12.0 software package.

Immunohistochemical staining showed the SDF-1 protein was strongly expressed at the gingival tissues around tooth extraction wound at early stage, mainly in the cytoplasm and intercellular substance of the stratum spinosum and stratum basale, and stained more obviously closer to the stratum basale. Four days after tooth extraction, the expression of SDF-1 in the stratum basale became more evident, and it is also positive inside endothelial cells of granulation tissues. Seven days after tooth extraction, the staining became uniform in the gingival epithelium, and a few positive staining of vascular endothelial cells could be found in lamina propria; Ten days after tooth extraction, the staining characteristics were similar to the normal gingiva. RT-PCR results showed that SDF-1mRNA underwent a biphasic expression change during gingival wound healing. SDF-1 mRNA level reached peak at day 1 after tooth extraction (P<0.01) but decreased by day 2. However, the SDF-1 mRNA level increased again to a peak at day 4 and then returned to a normal level by day 10 (P>0.05).

SDF-1 is involved in the early soft tissue healing process, and may play a role as a promoter in tooth extraction healing. Supported by Young Scientists Award Fund of Shangdong Province(BS2013YY056) and Sci-tech Development Planning Program of Jinan City (2013-60).