The Expression Of Vascular Endothelial Growth Factors And Their Receptors In Experimental Pulpitis In The Rat

ObjectiveThe aim of this study was to investigate the expression and the effect of the vascular endothelial growth factors ( VEGF) and their receptors ( Fit -1) in experimental rat pulpitis, and to provide the important theoretic and experimental basis for the treatment strategy of pulpitis.MethodsBased on the execution time, the rats were classified into five groups: group 0d group 1d group 3d group 5d group 7d. Models of experimental rat pulpitis were established. After the rats were executed in 1d, 3d, 5d, 7d after operation respectively, intraheart perfusion was performed for 30min, then double maxillary molar tissues were intercepted rapidly and fixed in the paraformala-dehyde for 48h. The tissues were decalciumed in 10% EDTA for 3W. Tissue blocks were dehydrated in ascending' series of ethanol, cleared in xylene and embedded in paraffin. 7um thick Serial sections were cutted. The expression of VEGF and Fit - 1 in rat pulpal tissues was examined by using SABC immunohis-tochemical technique. MetaMorph image analysis software was used to determine the average gray value of VEGF and Fit - 1 positive cells in rat pulpal tissues. Statistical tests were performed by analysis of variance (ANOVA) , Tukey test and Pearson correlativity.ResultsPositive staining for VEGF was found in vascular endothelial cells, odonto-blasts and some fibroblasts of healthy pulp. In pulpitis, the expression of VEGFwas increased markedly. Strong specific staining for VEGF was observed in the inflammatory cells, such as neutrophils and monocytes, and the fainter signal of VEGF was detected in the odontoblasts and fibroblasts. Image analysis of VEGF indicated that the positive expression of VEGF in inflammatory pulp was rising significantly comparing with normal pulp ( P <0.01) , and among the inflammatory groups, the expression of VEGF in other inflammatory groups was increased highly significantly (P < 0. 01) , except group 3d and group 1d (P > 0. 05) , group 5d and group 3d ( P < 0. 05 ).Positive staining for Fit -1 was found in vascular endothelial cells, odontoblasts , prophase dentin and inflammatory cells. Image analysis of Fit -1 indicated that compared with the normal pulp, the expression of Fit - 1 in other inflammatory groups was increased highly significantly ( P < 0.01) , except group 1 d (P > 0. 05 ). In the inflammatory groups, the expression of VEGF in other inflammatory groups was increased significantly, except group 3d and group Id, group 5d and group 3d, group 7d and group 5d ( P >0.05) .Pearson correlativity analysis confirmed that the expression of VEGF was highly positively related with the expression of Fit - 1 in the pulpitis, r =0.717ConclusionOur immunohistochemical data showed that the expression of VEGF was strongly positive in the cells constituting the inflammatory infiltrate, whereas it had been found to be decreased in the fibroblasts and odontoblasts in the rat pulpitis. The results presented here suggested that VEGF might play an important role in the pulpitis, the inflammatory reaction in response to VEGF was mediated by Fit - 1 and thus showed a possible function for the VEGF - receptor Fit -1.