The Further Study of Calcium Channel Blocker and Steroid to Increase Secretion of Scar Fibroblast Decorin and Secretion of Collagenase in Human-Scar Carrying Animal Model

The formation of hypertrophic scar(HSC) is an abnormal wound-healing response after either thermal injury or partial-thickness skin damage. Because its pathogenesis is not clearly understood, it still cannot be controlled with satisfying results. It is found that the scar formation after thermal or other injuries differs from human races, individuals, ages, and even body positions and there were many studies discussed the topics about it. The previous study revealed that extracellular matrix molecules, cytokines, and proteinases may alter cell proliferation and migration and thus lead to the formation of hypertrophic scar. The mechanisms may relate to the inhibition of dermal fibrosis, the modulation of TGF-βor PDGF to inhibit the fibroblast proliferate or differentiate. Besides, induce apoptosis can also inhibit the scar formation. However, on the basis of the view of modern biology, any change in response to an injury must be accompanied by a change in gene expression. In the previous study, these altered genes were related to proto-oncogenes, apoptosis, immune regulatory genes, cytoskeletal elements, metabolism, and so forth. So we evaluate the gene expressions in the formation of the scars may be valuable for finding scar-related genes, for understanding the pathologic alteration, specific marker and the therapeutic strategy. In our previous study (NSC89-2314-B -182A-151), the animal model with human scar implanted into nude mice (BALB/c) has been established successfully and the effects of Gentle Yag Laser, verapamil, and combination therapy with verapamil and kanacort have been studied and compared both in vitro and in vivo after 4 weeks treatment. In the aspects of scar size and weight, decorin stain, fibroblast culture to detect the fibroblast activity, the therapeutic groups have much better response.We have submitted the paper for publication. There are two mechanism involving HSC formation. One is high fibroproliferative activity resulting in excessive collagen accumulation. The second is disorganized collagen fibers due to reduction in some proteoglycan such as decorin. The expression of decorin and collagenase genes of HSC fibroblasts can be blocked by some cytokines such as TGF-β (Scott, 1998). Our previous study has indirectly proved that corticosteroids and calcium channel blockers can restore the synthesis of decorin and collagenase which has been retarded by these cytokines. Previous studies in the literatures with calcium channel inhibitors have not highlighted modulation of decorin to date. We present the first evidence that a calcium channel inhibitor augmented decorin expression. However, the increased amount of decorin was scored by microscope only in our study. More sensitive quantification using biochemical methods are needed for giving us stronger evidence. We hypothesize that the calcium channel inhibitors can stimulate the decorin mRNA expression of HSC fibroblasts. Besides, corticosteroids have been reported to increase the expression of decorin by 2.5 fold in renal podocytes recently. However there are few reports regarding the effect of steroids to the decorin for the HSC fibroblasts. In this project the level of decorin and collagnease mRNA was determined by RT-PCR. In the first year studies, we will quantitate the mRNA expression of HSC fibroblasts cultured in the FPCL (Fibroblast-Populated Collagen Lattice) medium in the presence of corticosteroids or calcium channel blockers of different concentrations. In our second year studies the mRNA expression of HSC fibroblasts obtained from corticosteroids or calcium channel blockers - treated human scars implanted in the nude mice will be measured. In the third year studies the combination therapy with corticosteroids and calcium channel blockers of different concentration will be tested for their efficacy of increasing the expression of decorin and collagenase and compared with single drug therapy. After this studies we can confirm that the combination therapy can restore more amount of decorin and collagnease than single drug therapy.

Project ID:PC9808-0598
External Project ID:NSC98-2314-B182-017