[Effects of He-Ne laser irradiation on the expression of transforming growth factor beta1 during experimental tooth...

The purpose of this study is to investigate the effect of He-Ne laser irradiation on the expression of transforming growth factor beta1 (TGF-beta1) during experimental tooth movement in rabbits.

Thirty-five rabbits were used in this study. The animals were randomly divided into 7 groups equally: normal group and experimental (1, 3, 5, 7, 14, 21 days) groups, 5 rabbits in each group. An orthodontic appliance, consisting of a coil spring was ligated to the bilateral first maxillary molar and connected to an orthodontic wire ligated onto the incisors, and exerting a force of approximately 80 g. The left side was used as control, and the right side was designed as irradiated side. The animals from each group were sacrificed at the time discontinued. The histological sections were proceeded with immunohistochemical staining of TGF-beta1. Then it was analyzed by Computer Image Analyzing System and statistically processed with SPSS10.0 software package for the paired Student's t test.

The expression of TGF-beta1 was demonstrated in the area of tension and pressure of periodontium tissue in both of the irradiated and control sides. The TGF-beta1 staining in the pressure area of the irradiated side decreased significantly at 1 day (P<0.05) compared with the control side. TGF-beta1 staining increased significantly at 3 to 5 days in the pressure area (P<0.05). But in the tension area of the irradiated side, TGF-beta1 staining were significantly increased at 3 to 7 days (P<0.05). The peak value of the area of tension and pressure both appeared at the same time of the 5th day.

It is concluded that He-Ne laser irradiation can effectively accelerate the expression of TGF-beta1 in periodontal tissue of rabbits during experimental tooth movement.