AIM: To investigate the effect of different concentrations of 10-hydroxycamptothecin(HCPT)on the cell cycle and cytotoxicity of human Tenon's capsule fibroblasts(HTFs), and to explore its mechanism in anti-fibrosis.

METHODS:The Tenon's capsule tissue of fresh eyes(<6h)of our hospital eye bank was taken, in vitro culture of fibroblasts was done by tissue block culture; A flow cytometry(FCM)was used to evaluate the effect of different concentrations of HCPT(0, 0.25, 1, 4mg/L)and mitomycin C(MMC: 0, 0.025, 0.1, 0.4mg/L)on HTFs cell cycle; Trypan blue staining was adopted to determine whether the inhibitory effect of HCPT and MMC on HTFs was caused by their cytotoxicity; RT- PCR was employed to detect the level of Smad7mRNA gene expression of HTFs after HCPT and MMC were used for 24h.

RESULTS:HTFs were cultured successfully in vitro, and can be used in our study; compared with the control groups, the cell cycle of HTFs which was affected by different concentrations of HCPT was significantly different in G2 phase(P<0.05). As for MMC, there were significant differences in G1 phase between groups with different concentrations of MMC and the control group(P<0.05). There was no significant difference in the rate of HTFs living cells between HCPT group(or MMC group)to which HCPT and MMC were added for 24h and the control group(P>0.05). After HFTs was affected by 0.4mg/L MMC or 4mg/L HCPT for 24h, RT PCR found that the level of Smad7 mRNA expression was significantly increased(P<0.05).

CONCLUSION: HCPT mainly blocks HTFs in G2 phase, MMC mainly impacts the G1 phase. The inhibitory effect of HCPT and MMC on HTFs proliferation is not relevant to cytotoxicity induced by the two drugs. The mechanism that HCPT inhibits the proliferation of HTFs may be due to the increasing Smad7 mRNA expression to block TGF-β signaling pathway.