Inducible nitric oxide synthase links NF-κB to PGE2 in polyunsaturated fatty acid altered fibroblast in-vitro wound healing

Abstract

BackgroundThis study investigated mechanisms of altered fibroblast collagen production induced by polyunsaturated fatty acids. 3T3-Swiss fibroblasts were grown in medium containing either eicosapentaenoic or arachidonic acid. The effects of nuclear factor-kappaB activation by lipopolysaccharide on inducible nitric oxide synthase, nitric oxide, prostaglandin E2, collagen production, and in-vitro wound healing were studied.ResultsEicosapentaenoic acid treated cells produced less prostaglandin E2 but had increased inducible nitric oxide synthase expression, nitric oxide production, collagen formation, and recoverage area during in-vitro wound healing than cells treated with arachidonic acid. Activation of nuclear factor-kappaB with lipopolysaccharide increased inducible nitric oxide synthase expression, the production of nitric oxide, prostaglandin E2, collagen, and the in-vitro wound recoverage area. The nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester, decreased lipopolysaccharide-induced nitric oxide, but the amount of nitric oxide was greater in eicosapentaenoic acid treated cells. NG-nitro-L-arginine methyl ester plus lipopolysaccharide treatment increased collagen production and cellular recoverage area while treatment with NG-nitro-L-arginine methyl ester alone decreased it in wounded fibroblasts.ConclusionThe activation of the NF-κB pathway and PGE2 can be linked by the cross-talk of iNOS and NO in the PUFA altered fibroblast collagen production and wound healing. Additional studies are needed to determine how polyunsaturated fatty acids can be used as adjuvants in combination with other treatments (i.e, drugs) to design therapies to either enhance healthy collagen production or inhibit production and reduce fibrosis.

Fatty Acid Profile and Biological Activities of Linseed and Rapeseed Oils

“…There are contradictory results on PUFA-associated wound healing activity in vitro and in vivo , which may be explained at least in part by the different mode of administration (topical application versus diet supplementation), different concentrations, sources of PUFA and wound healing assays used [6,16,17,18]. It has been postulated and rebutted that PUFA may have stimulatory role in wound healing [6,16,17,18]. Thus, there is still a need for comprehensive evaluation of PUFA-mediated effects during wound healing process involving inflammation, cell proliferation and tissue remodeling [19].…”

“…Nitric oxide has been implicated in wound healing because inducible nitric oxide synthase (iNOS) deficiency caused significant impairment in wound healing [20]. The activation of the nuclear factor-kappaB (NF-κB) pathway and prostaglandin E 2 (PGE 2 ) may be linked by the cross-talk of iNOS and nitric oxide during collagen production and wound healing in PUFA-stimulated fibroblasts [18]. Eicosapentaenoic acid (EPA) treatment resulted in lower PGE 2 levels and increased iNOS expression, nitric oxide production, collagen formation and recoverage area during wound healing compared to arachidonic acid (AA)-treated fibroblasts [18].…”

“…The activation of the nuclear factor-kappaB (NF-κB) pathway and prostaglandin E 2 (PGE 2 ) may be linked by the cross-talk of iNOS and nitric oxide during collagen production and wound healing in PUFA-stimulated fibroblasts [18]. Eicosapentaenoic acid (EPA) treatment resulted in lower PGE 2 levels and increased iNOS expression, nitric oxide production, collagen formation and recoverage area during wound healing compared to arachidonic acid (AA)-treated fibroblasts [18]. Moreover, lipopolysaccharide (LPS)-induced activation of NF-κB pathway resulted in more pronounced changes in the gene expression in EPA-treated fibroblasts compared to AA-treated cells [21].…”