Fatty acid extracts from Lucilia sericata larvae promote murine cutaneous wound healing by angiogenic activity

Abstract

Background: fatty acids are considered to be effective components to promote wound healing and Lucilia sericata larvae are applied clinically to treat intractable wounds. We aimed to investigate the effect of fatty acid extracts from dried Lucilia sericata larvae on murine cutaneous wound healing as well as angiogenesis.

Results: On day 7 and 10 after murine acute excision wounds creation, the percent wound contraction of fatty acid extracts group was higher than that of vaseline group. On day 3, 7 and 10 after wounds creation, the wound healing quality of fatty acid extracts group was better than that of vaseline group on terms of granulation formation and collagen organization. On day 3 after wounds creation, the micro vessel density and vascular endothelial growth factor expression of fatty acid extracts group were higher than that of vaseline group. Component analysis of the fatty acid extracts by gas chromatography-mass spectrometry showed there were 10 kinds of fatty acids in total and the ratio of saturated fatty acid, monounsaturated fatty acid and polyunsaturated fatty acid (PUFA) was: 20.57%:60.32%:19.11%.

Conclusions: Fatty acid extracts from dried Lucilia sericata larvae, four fifths of which are unsaturated fatty acids, can promote murine cutaneous wound healing probably resulting from the powerful angiogenic activity of the extracts.

Figure 1

Histological compare in the character of wound healing on day 3 (100× magnification). a(HE), d(Masson Trichrome) in study group and c(HE), f(Masson Trichrome) in positive control group showed the thick granulation tissue layer with robust newly-formed vessels as well as plenty of inflammatory and repair cells. b(HE), e(Masson Trichrome) in negative control group showed massive necrotic substances and a thin granulation tissue layer. EP, epithelium; GT, granulation tissue.

Figure 2

Immunohistochemical examination of MVD and VEGFA expression on day 3 (400× magnification). There was higher MVD (Black arrow) in study group (a) and positive control group (c) as compared with negative group (b). VEGFA was mainly expressed in neutrophils, macrophages, endothelial cells and fibroblasts within granulation tissue (Black triangle). Compared with negative control group (e), the study group (d) and positive control group (f) expressed more with respect to VEGFA.

Figure 3

VEGFA mRNA and protein expression on day 3. VEGFA mRNA expression revealed by RT-PCR (a) and VEGFA protein expression determined by western-blot (b) and its relative expression (c and d) showed the expression of study group was the highest and the expression of negative control group was the lowest(*, compared with negative control group; **, compared with positive control group).

Figure 4

Total ion chromatography of fatty acids extract from Lucilia sericata larvae. There are ten different peaks representing ten kinds of fatty acids.