Experimental Research Of Leptin In The Pathogenesis Of Primary Pterygium

Objective To investigate the different expressions of leptin and its receptors in primary pterygia and normal conjunctivae.Methods Leptin and its receptors expressions were detected in 23 primary pterygia and 7 normal conjunctivae by SABC immunohistochemical method.Results Expression of Lp was weakly postive on the epithelial basal cells and negative on th stromal fribroblasts of normal conjunctivae. It was strong postive on the epithelium, fibroblasts and vascular endothelial cells of primary pterygium tissues. The difference was statistically significant. (Epithelim:P= 0.000; Stroma:P =0.026) Expression of LpR was postive on both of conjunctivae and primary pterygia, and there was no statistically significanct difference. (Epithelim:P=0.331; Stroma:P =0.675).Conclusion Leptin and its receptors might play roles in the pathogenesis of the pterygium. Objective This study aims to elucidate the relationship between the expression of leptin, vascular endothelial growth factor (VEGF), and microvascular density (MVD) marked by endoglin (CD 105) antibody of primary pterygium.Methods The SABC immunohistochemical staining in paraffin-embedded tissues was used to investigated the expression of leptin, VEGF in 23 primary pterygia and 7 normal conjunctiva specimens. The antibody against CD 105 was used to display vascular endothelial cells, and MVD was examined by counting the CD105-positive vascular endothelial cells. The correlations of leptin, VEGF, and CD105-MVD were analyzed with SPSS 11.0.Results Over-expression of leptin and VEGF was significantly observed in primary pterygia in contrast to normal conjunctivae. The CD105-MVD in pterygia averaged 19.22±6.68 was higher than that in normal conjunctivae averaged 4.00±2.15 (P=0.000). CD105-MVD in pterygia had significant positive association with leptin (the epithelium:P=0.002; the stroma:P=0.022) and VEGF expression in the stroma (P=0.041), but no correlation with VEGF in the epithelium (P=0.199).Conclusion Over-expression of leptin and VEGF might play roles in the pathogenesis of angiogenesis in primary pterygium. Objective To explore the effect of recombinant human leptin (rhLp) on proliferative activity of human pterygium fibroblast cells (HPFs).Methods HPFs were isolated and cultured and treated with different concentrations of rhLp. CCK8 assay, flow cytometry and Western blot were used to observe the changes of cell proliferation, cell cycle and proliferating cell nuclear antigen (PCNA) protein expression, respectively.Results Leptin could significantly improve proliferation of HPFs. The effect was in a certain dose-and time-dependent by CCK8 assay. In the folw cytometry analysis, it was found that rhLp could promote HPFs to enter S phrase from G0/G1 phrase. The expression of PCNA was increased in HPFs treated with the raised concentration of rhLp in vitro.Conclusion Leptin could promote the proliferation of HPFs. The increase expression of leptin may play an important role in primary pterygium pathogenesis. Objective To observe the effect of rhLp on invasion of HPFs in vitro.Methods HPFs were cultured and treated with rhLp at different concentrations (10,100, 1000ng/ml) for 12h. HPFs without rhLp treatment were used as control group. The effect of leptin on mRNA and protein expression of MMP2 and MMP9 in HPFs was detected by realtime-PCR and Western blot, respectively. Transwell chamber assay was performed to determine the effect of different concentrations of rhLp on the invasion capability of HPFs.Results Real time fluorescent quantitative PCR analysis revealed that the level of MMP2 and MMP9 mRNA of 100ng/ml rhLp was significantly higher than that of control group (P<0.05). Western blot revealed that the expression of MMP2 and MMP9 protein of different concentration rhLp groups was all significantly higher than that of control group (P<0.05). The MMPs expression of 100ng/ml rhLp group was higher than 10ng/ml(P<0.05), while there was no significantly difference between the group of 10 and 1000ng/ml rhLp. The invasion ability of HPFs which were treated by 100ng/ml rhLp was significantly enhanced in contrast to those in control group(P=0.000).Conclusion Leptin significantly increases the invasion capabilities of HPFs in vitro. The mechanism may be related with up-regulation of MMPs level.