Accelerated Healing of Diabetic Wounds Treated with L-Glutamic acid Loaded Hydrogels Through Enhanced Collagen Deposition and Angiogenesis: An In Vivo Study

Ponrasu Thangavel,Balaji Ramachandran,Suguna Lonchin,Vignesh Muthuvijayan,Ramya Kannan,Sudip Chakraborty

doi:10.1038/s41598-017-10882-1

Ponrasu Thangavel, Balaji Ramachandran + Show 4 more

Open Access

https://doi.org/10.1038/s41598-017-10882-1

Copy DOI

Abstract

We have developed L-glutamic acid (LG) loaded chitosan (CS) hydrogels to treat diabetic wounds. Although literature reports wound healing effects of poly(glutamic acid)-based materials, there are no studies on the potential of L-glutamic acid in treating diabetic wounds. As LG is a direct precursor for proline synthesis, which is crucial for collagen synthesis, we have prepared CS + LG hydrogels to accelerate diabetic wound healing. Physiochemical properties of the CS + LG hydrogels showed good swelling, thermal stability, smooth surface morphology, and controlled biodegradation. The addition of LG to CS hydrogels did not alter their biocompatibility significantly. CS + LG hydrogel treatment showed rapid wound contraction compared to control and chitosan hydrogel. Period of epithelialization is significantly reduced in CS + LG hydrogel treated wounds (16 days) compared to CS hydrogel (20 days), and control (26 days). Collagen synthesis and crosslinking are also significantly improved in CS + LG hydrogel treated diabetic rats. Histopathology and immunohistochemistry results revealed that the CS + LG hydrogel dressing accelerated vascularization and macrophage recruitment to enhance diabetic wound healing. These results demonstrate that incorporation of LG can improve collagen deposition, and vascularization, and aid in faster tissue regeneration. Therefore, CS + LG hydrogels could be an effective wound dressing used to treat diabetic wounds.

Highlights

Wound dressing materials are used as a protective barrier against pathogens during the wound healing process
As L-glutamic acid is a precursor for collagen synthesis and is significantly cheaper than poly(glutamic acid), we hypothesize that an effective wound dressing material can be developed by loading chitosan hydrogels with L-glutamic acid
Results showed elevated levels of CD68 positive cells in CS and CS + L-glutamic acid (LG) hydrogel-treated tissues on day 8 compared to control. These results indicated that CS and CS + LG hydrogel dressings are probably involved in the early stage of inflammation and aid in recruiting the inflammatory cells like monocytes, macrophages, and neutrophils

Summary

Introduction

Wound dressing materials are used as a protective barrier against pathogens during the wound healing process. Alginate, chitosan, and poly(γ-glutamic acid) were blended and prepared as hydrogels (AL-CS-PGA)[22] This hydrogel was used as a dressing in type I diabetic rats for wound healing studies. The silk sericin loaded hydrogel treatment showed improved cell proliferation and epithelialization in normal rats[25] These studies have evaluated poly(glutamic acid)-based scaffolds, there are no reports on the potential of directly using L-glutamic acid for treating normal or diabetic wounds. As L-glutamic acid is a precursor for collagen synthesis and is significantly cheaper than poly(glutamic acid), we hypothesize that an effective wound dressing material can be developed by loading chitosan hydrogels with L-glutamic acid In this manuscript, we have reported the preparation of L-glutamic acid loaded chitosan hydrogel via physical crosslinking and have evaluated its potential in diabetic wound healing. These CS + LG hydrogels have been characterized for structural morphology, swelling, release, in vitro biodegradation, cytocompatibility, and in vivo diabetic wound healing

Methods

Results

Conclusion