Effects of osthole on apoptosis and TGF-β₁ of hypertrophic scar fibroblasts

Abstract

Osthole, 7-methoxy-8-[3-methylpent-2-enyl]coumarin (1), was extracted from a Chinese herb Cnidium monnieri (L.) Cuss. It showed immunity strengthening, anti-tumor, anti-hepatitis, and anti-osteoporosis activities in previous studies. Our goals are to study the effects of 1 on cell proliferation and TGF-β of hypertrophic scar fibroblasts. Our results showed that 1 induced apoptosis and inhibited cell proliferation in hypertrophic scar fibroblasts. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that its IC₅₀ value toward hypertrophic scar fibroblasts was 15.5 ± 2.2 μmol/l. Furthermore, the results of cell growth curve matched with the above results. Inducing apoptosis by 1 in hypertrophic scar fibroblasts was assessed by various morphological and biochemical characteristics, including cell shrinkage, chromatin condensation, membrane blebbing, formation of apoptotic bodies, and DNA ladder formation. A typical ‘Sub-G₁ peak’ was also checked through flow cytometry. We used immunohistochemistry to observe the expression of TGF-β₁. Also, we found that 1 could obviously inhibit the expression of TGF-β₁ of fibroblasts derived from hypertrophic scar compared with the control group (P < 0.05). These results suggest that 1 inhibits the growth of hypertrophic scar fibroblasts through apoptosis and decreases the expression of TGF-β₁.

Keywords:

• osthole
• hypertrophic scar
• apoptosis
• TGF-β₁