Experimental Research Of NGF, TrkA And P75 In Pterygium

Objective To investigate the expression of NGF, trkA and p75 in pterygium, and toanalyse their correlation with form of pterygium.Methods NGF, trkA and p75 expression was detected in 30 pterygium tissues and 5normal conjunctiva tissues by immunohistochemical method.Results Expression of NGF, trkA and p75 was significantly observed in epithelium,fibroblasts and vascular endothelial cells of pterygium tissues. Expression of NGF and trkAwas observed in epithelium and fibroblast of normal conjunctiva. Expression of p75 wasonly observed in epithelium of normal conjunctiva.Conclusion NGF, trkA and p75 possibly participate in genesis and development ofpterygium. Objective To determine localisation of p75 andα-SMA (α-smooth muscleactin) in pterygium tissues.Methods Three normal conjunctiva and ten pterygium were surgically collected,and three normal cornea were collected from eye bank. Formalin fixed and paraffinembedded tissue sections were incubated with trkA, p75 polyclonal antibodies andα-SMA monoclonal antibody, and then examined by immunohistochemistry.Immunolocalisation of p75 andα-SMA was detected in pterygium and primarycultured fibroblasts by confocal microscopy.Results Expression of p75,α-SMA and trkA was detected significantly infibroblasts of pterygium, p75 and trkA was examined in epithelium cells of pterygium,normal conjunctiva and cornea. In the pterygium head, p75 as well asα-SMA washeterogeneously expressed in cytoplasm of fibroblasts, whereas the expression was lessmarked in the body.Conclusion It is suggested that p75 andα-SMA were concentrated in the sameposition of pterygium head, and p75 was possibly involved in cell proliferation. Objective To investigate proliferative effects ofβ-NGF (Nerve growth factor) onhuman pterygium fibroblasts(HPF), and to analyse the pathogenesis mechanism ofpterygium.Methods trkA and p75 expression was detected in HPF by immumofluorescencemethod. HPF were incubated with various concentrations ofβ-NGF. The efficacy ofβ-NGF on this cell line was assessed with MTT assay. Cell proliferation was evaluated bymeasurement of PCNA.Results Expression of trkA and p75 was observed in HPF. Maximum stimulationoccurred at 48h for HPF. Incubation of HPF withβ-NGF resulted in a significant increasein PCNA compared with that of control cells.Conclusion The findings demonstrate the potential proliferative effect ofβ-NGFbinding to trkA and p75 on HPF. Objective To investigate the growth inhibition effects and the mechanisms of trkAinhibitor on human pterygium fibroblast.Methods trkA and p75 expression was detected in HPF by immumofluorescencemethod. After being treated with 10～80nmol/L trkA inhibitor for 24～96h, the growthactivities of fibroblasts were studied by MTT colorimetry. Caspase-3 was inspected infibroblasts by spectrophotometric method. The apoptosis was detected by flow cytometery(FCM).Results trkA inhibitor could effectively inhibit the in vitro growth of humanpterygium fibroblast in time and dose dependent manners. Caspase-3 expression wasincreased. The rates of apoptotsis were 8.26 %～29.62 % (P＜0.01).Conclusion trkA inhibitor could induce apoptosis of human pterygium fibroblasts.Induicing apoptosis through changing the ratio of trkA and p75 in fibroblasts andup-reguating caspase-3 was probably one of its molecular mechanisms.