Dynamic study on expression of gelatinase A and its natural inhibitor during invasion and metastasis of induced lung cancer in Wistar rats / 中华肿瘤杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the dynamic expression and its relation of gelatinase A (MMP-2), its natural inhibitor (TIMP-2) and DNA index (DI) changes during carcinogenesis, invasion and metastasis in Wistar rats.</p><p><b>METHODS</b>Squamous cell carcinoma of lung was induced with 3-methylcholanthrene (MCA) and diethyinitrosamine (DEN) in iodized oil by left intra-bronchial instillation in 80 Wistar rats. Immrno histochemistay (IHC) and in situ hybridigation were used in the monitor of MMP-2, TIMP-2 proteins and mRNA expression during invasion and metastasis of lung cancer in these rats, DNA index (DI) value was measured by guantitatove image analysis on feulgen stained sections.</p><p><b>RESULTS</b>Along with the carcinogenis, the average poritive MNP-2 and TIMP-2 expressions increased, with positive rates of 8.5% - 85.7% and 6.4% - 35.7%. DI value also underwent the same changes (1.47 +/- 0.54) - (2.87 +/- 0.55). The difference of MMP-2 expression in carcinoma in situ versus early carcinoma and early carcinoma versus metastatic carcinoma are statistically significant (P < 0.05). Companing lung carcinome, the contrel group and non-cancerous lesions, the elevation of MNP-2 and TIMP-2 expressions were also sigmificant (P < 0.01). The DI elevation in carcinoma in situ and dysplasia were obviously significant (P < 0.05). Meanwhile a negative relation was noted in TINP-2 and MMP-2 expressions during carcinogenesis. There was a positive relation between MMP-2 expression and DNA poikiloidy (P < 0.01), which was related to the close relationship between MMP-2 and metastasis in advanced rat lung carcinoma (P < 0.05).</p><p><b>CONCLUSION</b>The excess degradation and disruption of basement membranes by activated MMP-2 may be a key step in inducing lung cancer invasion and metastasis. The imbalance between MMP and TIMP may be a critical factor which affects biologic behavior of lung carcinogenesis, invasion and metastasis.</p>