CCL4 and fibrosis: According to our study, the most interesting finding was that the combinational delivery of uPA and MMP-8 genes was more effective than mono-gene therapy in reversal of fibrosis and is in agreement with Lyn et al. respect to sinergystic effect of fibrosis regression (Figure 3), increment of functional activity of MMP2 and MMP-9 (Figure 4D) involved in the degradation of the excessive collagens deposition, in a persistent hepatic fibrosis animal model intoxicated continuosly with CCL4.