Inhibitory effects of lanthanum chloride on extracellular matrix in injury tissues of rats

The propose of the present study is to investigate the effects of lanthanum chloride (LaCl3), a rare earth compound, on extracellular matrix molecules in rat wound tissues, hoping to provide a clue for further study in reducing excessive extracellular matrix formation in trauma and burn, as well as in fibrous disorders. In order to elucidate its action mechanism, we investigated its effects on fibroblast apoptosis, intracellular calcium, collagen synthesis and expression, and fibronectin mRNA expression. We found that treatment with 0.25 ml of 50 mM (1.5 mg/injection) LaCl3 for three consecutive days induced fibroblast apoptosis and inhibited collagen synthesis and expression. Comparing to control, at day 14 after wounding, apoptosis and the level of intracellular calcium in wound tissues were significantly increased, but at day 28 after wounding, apoptosis was not continually increased and gradually became normal. In contrast, the amount of 3H-proline incorporation and the expression of type I and III collagen decreased at days 14 and 28 after wounding by LaCl3-treatment. The expression of fibronectin mRNA was not significant changed at days 14 and 28 after-wounding by LaCl3-treatment as compared to the control. The results suggest that LaCl3 may reduce the extracellular matrix formation at certain concentrations during wound healing and be worth further study as an anti-fibrous agent. Because lanthanides have been used to clinical treatment with antibacterial agents in burn, it may be more suitable for the treatment of severe burn.