Quantifying tissue level ischemia: Hypoxia response element-luciferase transfection in a rabbit ear model

The wound healing effect of botanicals and pure natural substances used in in vivo models

Repairing the wound is a multistep process that includes the spatial and temporal synchronization of a different range of cell types to increase the speed of wound contraction, the proliferation of epithelial cells, and collagen formation. The need for proper management of acute wounds to be cured and not turned into chronic wounds is a significant clinical challenge. The traditional practice of medicinal plants in many regions of the world has been used in wound healing since ancient times. Recent scientific research introduced evidence of the efficacy of medicinal plants, their phyto-components, and the mechanisms underlying their wound-repairing activity. This review aims to briefly highlight the wound-curing effect of different plant extracts and purely natural substances in excision, incision, and burn experimental animal models with or without infection of mice, rats (diabetic and nondiabetic), and rabbits in the last 5 years. The in vivo studies represented reliable evidence of how powerful natural products are in healing wounds properly. They have good scavenging activity against Reactive oxygen species (ROS) and anti-inflammatory and antimicrobial effects that help in the process of wound healing. It is evident that incorporating bioactive natural products into wound dressings of bio- or synthetic polymers in nanofiber, hydrogel, film, scaffold, and sponge forms showed promising results in different phases of the wound-curing process of haemostasis, inflammation, growth, re-epithelialization, and remodelling.

A review of animal models from 2015 to 2020 for preclinical chronic wounds relevant to human health

SIGNIFICANCE

Chronic wounds fail to heal in a timely manner and exhibit sustained inflammation with slow tissue repair and remodelling. They decrease mobility and quality of life, and remain a major clinical challenge in the long-term care of many patients, affecting 6.5 million individuals annually in the U.S., decreasing mobility and quality of life. Treatment costs are a major burden on the U.S. healthcare system, totalling between $25 and $100 billion annually. Chronic wound severity depends upon several factors such as comorbidities, severity of tissue damage, infection and presence of necrosis and vary greatly in their healing mechanisms. In vivo animal models are critical for studying healing pathways of chronic wounds and seek to replicate clinical factors for trials of topical, systemic, and device-based therapeutics. This comprehensive review discusses murine, rat, lapine, canine, feline and porcine models of chronic wounds.

RECENT ADVANCES

Foundational chronic wound models for several species are discussed together with refinements and advances in the time period between 2015 and 2020 which have the potential for broad utility in investigating biological and device-based wound treatment therapies for human health.

CRITICAL ISSUES

Chronic wounds fail to heal in a timely manner and have differing aetiologies, rendering no single in vivo animal model universally applicable.

FUTURE DIRECTIONS

Further studies are required to develop clinically relevant chronic wound animal model which reflect the clinical reality of the various influences of age, disease, comorbidities and gender on delayed healing and enhance understanding of the biological processes of human wound healing.