The expression of vascular endothelial growth factor in mast cells promotes the neovascularisation of human pterygia.

Aims: To analyse the relationship between mast cells and vascularisation in pterygia and to determine whether mast cells play an important role in the vascularisation of pterygia through the secretion of vascular endothelial growth factor (VEGF).

Methods: Fifty-two pterygia and forty-four normal conjunctiva samples were obtained. Formalin-fixed, paraffin wax-embedded tissues were analysed by immunohistochemistry with CD31 and VEGF antibodies. Dual-immunofluorescence was used to see the location of mast cells and microvessels. To prove that mast cells have the function of secreting VEGF, we used dual-immunofluorescence, toluidine blue stain and immunohistochemisty study.

Results: Mast cells are located near the microvessels. The numbers of mast cells in pterygia (10.8 ± 2.7) were significantly higher compared with those in conjunctiva (4.7 ± 2.4, p<0.01). The numbers of microvessels in pterygia (20.7 ± 5.4) were also significantly higher than those in conjunctiva (9.3 ± 2.9, p<0.01). There was an association between mast cell count and microvessel density in pterygia (r=0.77, p<0.001). The cells were positive for toluidine blue staining and could express VEGF through a serial section stain. Dual-immunofluorescence showed that VEGF and mast cell tryptase (MCT) were expressed in the same cell.

Conclusion: The results suggest that mast cells have a function in the vascularisation of pterygia through the secretion of VEGF.