Effects of fibroin microcarriers on inflammation and regeneration of deep skin wounds in mice

Abstract

The process of tissue regeneration following damage takes place with direct participation of the immune system. The use of biomaterials as scaffolds to facilitate healing of skin wounds is a new and interesting area of regenerative medicine and biomedical research. In many ways, the regenerative potential of biological material is related to its ability to modulate the inflammatory response. At the same time, all foreign materials, once implanted into a living tissue, to varying degree cause an immune reaction. The modern approach to the development of bioengineered structures for applications in regenerative medicine should be directed toward using the properties of the inflammatory response that improve healing, but do not lead to negative chronic manifestations. In this work, we studied the effect of microcarriers comprised of either fibroin or fibroin supplemented with gelatin on the dynamics of the healing, as well as inflammation, during regeneration of deep skin wounds in mice. We found that subcutaneous administration of microcarriers to the wound area resulted in uniform contraction of the wounds in mice in our experimental model, and microcarrier particles induced the infiltration of immune cells. This was associated with increased expression of proinflammatory cytokines TNF, IL-6, IL-1β, and chemokines CXCL1 and CXCL2, which contributed to full functional recovery of the injured area and the absence of fibrosis as compared to the control group.

Novel Biodegradable Polymeric Microparticles Facilitate Scarless Wound Healing by Promoting Re-epithelialization and Inhibiting Fibrosis

“…For recombinant spidroin, the alternation of short hydrophobic and hydrophilic regions is characteristic, which allows the surface of the microgel to exhibit either hydrophobic or hydrophilic properties, depending on the environment. F/G MPs were obtained by cryodestruction of spongy scaffolds (21, 31). The resulting F/G MPs are the fragments of a scaffold with a complex surface, providing a large surface area for cell adhesion and proliferation.…”

“…Deep skin wounds were introduced according to previously published protocol (21). Briefly, mice were anesthetized with i.p.…”

“…Five days following the induction of deep skin wounds, mice were injected with anesthesia, two skin samples 15 mm × 15 mm surrounding the injury site were excised and subsequently fixed one in 4% PFA solution and another one in Bouin's solution (saturated aqueous picric acid, formalin and glacial acetic acid in ratio 15:5:1) and a histological analysis of the tissue was carried out, as previously described (21). For re-epithelialization measurement, skin samples were stained by Mallory stain and examined using an inverted Axiovert 200 M microscope (Carl Zeiss, Germany) and an AxioCam MRC 5 camera (Carl Zeiss, Germany).…”

“…To answer these questions, we have evaluated two types of previously described silk-based MPs, generated from fibroin/gelatin (20, 21) scaffolds or spidroin (22–24) hydrogels and characterized their regenerative and inflammatory potential in vivo in the model of murine deep skin wounds, as well as direct effects on inflammatory and profibrotic genes expression in several cell types involved in skin regeneration in vitro . We have demonstrated that, while possessing similar proregenerative potential, these vehicles are remarkably different in their interaction with the host immune system.…”

Induction of ICAM-1 Expression in Mouse Embryonic Fibroblasts Cultured on Fibroin-Gelatin Scaffolds

“…We have previously engineered a fibroin-gelatin sponge scaffold which provides a substrate for the adhesion and proliferation of various cell types [ 1 ]. Subcutaneous injection of 200–400 μm fragments of this scaffold facilitated the regeneration of deep skin wounds in mice, apparently because of their immunomodulating activity [ 2 ]. One possible mechanism underlying the regenerative activity of gelatin-fibroin scaffolds could be an increase in the expression of adhesion molecules, which are involved in immune responses, by fibroblasts after they come into contact with the scaffold surface.…”