Wound Healing Lab Report

Chapter 1

Introduction

1.1 Wound A wound can be described as a defect or a break in the skin, resulting from physical or thermal damage or as a result of the presence of an underlying medical or physiological condition. Wounds generally classified based on the time at which it heals as acute and chronic. Acute and chronic wounds are at opposite ends of a spectrum of wound-healing types that progress toward being healed at different rates (1). A chronic wound is a wound that does not heal in an orderly set of stages and in a predictable amount of time the way most wounds do; wounds that do not heal within three months are often considered chronic. Chronic wounds seem to be detained in one or more of

In this phase, the wound contracts as new tissues are built. In addition, a new network of blood vessels must be constructed so that the granulation tissue can be healthy and receive sufficient oxygen and nutrients. In healthy stages of wound healing, granulation tissue is pink or red and uneven in texture. Dark granulation tissue can be a sign of infection, ischemia, or poor perfusion. In the final phase of the proliferative stage of wound healing, epithelial cells resurface the injury. The epithelialization is happens faster when wounds are kept moist and hydrated (2).

1.1.3 Remodeling phase

Also called maturation phase of wound healing, the phase is when collagen is remodeled from type III to type I and the wound fully closes. Generally the remodelling phase begins about 21 days after an injury and can continue for a year or more. The stages of wound healing are complex and fragile process. Failure to progress in the stages of wound healing can lead to chronic wounds. Factors that lead up to chronic wounds are venous disease, infection, diabetes, and metabolic deficiencies of the elderly. Careful wound care can speed up the stages of wound healing by keeping wounds moist, clean and protected from reinjury and infection. In the chronic wound condition, matrix Metalloprotease are over expressed which delays the wound healing mechanism

Chitosan is a linear copolymer of β (1=>4) linked 2-acetamido-2-deoxy-β-D-glucopyranose and 2-amino-2-deoxyβ-D-glycopyranose, easily obtained by deacetylation of chitin, an abundant polysaccharide found in nature as a component of exoskeletons of crustaceans and insects. Chitosan is reported to be biocompatible, biodegradable and non toxic, having some biomedical properties such as healing accelerator, antifungal, hemostatic, antimicrobial and analgesic.Chitosan has ability to enhance fibroblast proliferation, simulate type IV collagen synthesis, activate polymorphonuclear cells, modulate cytokine production, and stimulate giant cell migration in wound . Additionally chitosan serves as an excellent drug loadable matrix that can be used to produce prolonged drug release