The 3Rs in Experimental Liver Disease

Abstract

Patients with cirrhosis present multiple physiological and immunological alterations that play a very important role in the development of clinically relevant secondary complications to the disease. Experimentation in animal models is essential to understand the pathogenesis of human diseases and, considering the high prevalence of liver disease worldwide, to understand the pathophysiology of disease progression and the molecular pathways involved, due to the complexity of the liver as an organ and its relationship with the rest of the organism. However, today there is a growing awareness about the sensitivity and suffering of animals, causing opposition to animal research among a minority in society and some scientists, but also about the attention to the welfare of laboratory animals since this has been built into regulations in most nations that conduct animal research. In 1959, Russell and Burch published the book “The Principles of Humane Experimental Technique”, proposing that in those experiments where animals were necessary, everything possible should be done to try to replace them with non-sentient alternatives, to reduce to a minimum their number, and to refine experiments that are essential so that they caused the least amount of pain and distress. In this review, a comprehensive summary of the most widely used techniques to replace, reduce, and refine in experimental liver research is offered, to assess the advantages and weaknesses of available experimental liver disease models for researchers who are planning to perform animal studies in the near future.

Green tea and hyaluronic acid gel enhance fibroblast activation and improves the gingival healing post-third molar extraction

“…In other words, the synergism of green tea and hyaluronic acid affect the growth of fibroblast and suggest a positive effect in regeneration of soft tissues, such as mucosa present on the oral environment. In fact, evaluating the effect on fibroblasts in vitro is an important starting-point strategy mainly looking for reducing the experimental animal’s number in pre-clinical stages 40 . Moreover, fibroblasts are the main connective tissue cells and responsible to release molecules related with ECM constitution such as collagen fibers, desired during the repair of injures sites 41 – 43 .…”

Animal model considerations for chordoma research: reproducing the tumor microenvironment in vivo with humanized mice

“…The use of humanized mice to study immunotherapies has served to the advancement of medical research, to reduce animal testing and to accelerate drug testing and development ( 69 , 94 , 95 ). For example, the immune checkpoint inhibitor that we started this section talking about, keytruda ® , has been extensively used in humanized mice since its commercialization in 2013 in a wide array of cancers and in combination therapies ( 96 – 106 ).…”