Inhibitory Effect of Curcumin on Proliferation of Human Pterygium Fibroblasts

In order to investigate the effect of curcumin on proliferation and apoptosis of human pterygium fibroblasts (HPF) in culture and search for a new method to prevent the recurrence after pterygium surgery, HPF was incubated with 0-160 μmol/L curcumin for 24-96 h. The MTT method was used to assay the biologic activities of curcumin at different time points and different doses. The expression of proliferating cell nuclear antigen (PCNA) in each group was detected by immunohistochemistry. The cell cycle distribution was detected by flow cytometry (FCM). Admini- stration of 20-80 μmol/L curcumin for 24-72 h could significantly inhibit HPF proliferation in a dose- and time-dependent manner (P<0.05). After treatment with curcumin at different concentrations of 20, 40, 80 and 160 μmol/L for 24 h, FCM revealed there was a significant sub-G1 peak at each concentration. The number of HPF in G0/G1 phase was increased, while in S phase, it was decreased (P<0.05). At the concentration of 20-80 μmol/L, curcumin, in a dose-dependent manner (P<0.05), could inhibit the expression of PCNA in HPF. It was suggesterd that curcumin could significantly in- hibit the proliferation of HPF, make HPF arrest in G0/G1 phase and induce the apoptosis of HPF in a dose- and time-dependent manner.

Inhibitory Effect of PPARγ Agonist on the Proliferation of Human Pterygium Fibroblasts

The effects of DK2,a peroxisome proliferator-activated receptor γ agonist,on cultured human pterygium fibroblasts (HPFs) in virto were studied.The HPFs were incubated with 0-200 μmol/L DK2 for 12-72 h.The MTT method was used to assay the bio-activity of DK2 at different doses and time.The cytotoxic effect of DK2 was measured by LDH release assay.The cell cycle distribution and apoptosis were flow cytometrically detected.The expression of proliferating cell nuclear antigen (PCNA) in each group was detected by real-time PCR (RT-PCR) and Western blotting.The results showed that administration of 1-75 μmol/L DK2 for 12-72 h could significantly inhibit HPF proliferation in a dose-and time-dependent manner.DK2-treated cells did not release significant amount of LDH as compared with rosiglitazone-treated cells.After treatment with DK2 at concentrations of 15,25 μmol/L for 24 h,the number of HPFs in G 0 /G 1 phase was significantly increased while that in S phase was significantly decreased (P【0.05),leading to arrest at G 0 /G 1 phase.The apoptosis rates of HPF cells in drug-treated groups were significantly higher than the rate of control group (P【0.05).At the dosage range between 15-25 μmol/L,DK2 could inhibit the expression of PCNA mRNA and protein in HPFs in a dose-dependent fashion (P【0.05).It was concluded that PPARγ agonist can significantly inhibit HPF proliferation,resulting in the arrest at G 0 /G 1 phase,induce the apoptosis of HPFs,and suppress the synthesis of PCNA,in dose-and time-dependent manners.