| Summary: | 碩士 === 臺北醫學大學 === 藥學研究所 === 98 === Collagen is the most abundant protein in humans, it exists in the
connective tissue, and with high tension and tensile strength.The
collagen molecules assemble into functional integrity of tissue such
as skin, ligament, tendon, bone and cartilage which is the main
component of the extracellular matrix especially in human skin.
Collagen not only maintains the elasticity of skin and muscle but also
plays a promoting role during the process of wound healing. Tissue
repair has been divided into two phases, one is inflammatory phase, a
proliferation phase with synthesis of new connective tissue and
epithelial wound closure, the other is maturation phase once the
epidermal barrier has been re-established. The most important step of
wounding healing is the predominant form of collagen in the human skin
and is produced mainly by dermal fibroblasts.
Dynasore, a small organic molecule is a newly discovered
cell-permeable dynamin inhibitor, blocks the formation of
clathrin-coated vesicles through its inhibitory effects on the GTPase
activity of dynamin. Studies suggested that Dynasore enhances
TGF-β1–induced plasminogen activator inhibitor-1 expression, and might
be through JNK signal pathway in human MeT-5A cells. More and more
increasing evidences support not only the Smad pathway but also
others such as mitogen-activated MAPK and PI3K pathways play the
important role in TGF-β signaling. In addition, type I collagen
produce relating to TGF-β, PI3K pathway has reperted. In this study,
we investigated the effects of Dynasore on human skin fibroblast of
wound healing in vitro and in vivo.
Results of MTT assay showed that no adverse effect of Dynasore at the
concentration up to 100 μM when treated fibroblast. We found Dynasore
concentration-dependent increased procollagen type I induction cell
proliferation and migration. These effect might be due to induce
ERK1/2 and MMP-1 phosphorylation. Recently, TGF-β/Smad3 pathway is
recognized in controlling the wound healing, and PI3K also related.
Our data suggested Dynasore induced Smad3, Akt, mTOR phosphorylation
as well as procollagen type I expression. When treated with ERK, Akt
and mTOR inhibitors PD98059, LY294002 and rapamycin, respectively. We
found that only LY294002 can inhibit Dynasore -induced procollagen
type I protein expression. We conclued that Dynasore -induced
procollagen type I protein expression might be through PI3K/Akt
pathway. Although PD98059 inhibited the ERK1/2 phosphorylation and
MMP-1 expression, but it cannot suppress procollagen type I. indicated
that the formation of procollagen type I is indepented to ERK/MAPK
pathway and MMP-1.
In the in vivo study, ICR mice were created a 6 mm diameter wound on
the back by skin biopsy punch. Topical treating with Dynasore,
bFGF(basic fibroblast growth factor) as positive control for 14 days,
then recorded the wound area every day. Our results showed 3 mg/mL
Dynasore significantly promoted wound healing better than bFGF after
Day 5. In the mucositis animal model, 0.3 mg/mL Dynasore shown a
better outcome than control group.
Basic fibroblast growth factor(bFGF) regulates proliferation,
differentiation, migration and apoptosis. BFGF has the potential to
accelerate wound healing and improve the quality of wound healing by
regulating the balance of ECM synthesis and degradation. In this
study, Dynasore has the equivalent role of bFGF, is also a non-protein
compound, and stable when storage.We suggest that the effectiveness of
Dynasore including non-toxic in high dose, excellext effect and easy
to preserve. It might be a potential drug candidant in the future. The
purpose of this study is to find out a non-protein compound to replace
the use of bFGF on wound healing and anti-mucositis, we also wish can
develop a good and potential chemical for medical purpose in the drug
development.
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