Restraint stress-associated gastrointestinal injury and implications from the Evans blue-fed restraint stress mouse model

Abstract

The association between stress and gastrointestinal (GI) tract diseases is well established, while the exact mechanism remains elusive. As a result, it is urgent to establish mouse models to investigate restraint stress-associated GI leakage, but current models have their limitations. A new Evans blue-fed restraint mouse model has recently been developed that allows researchers to study restraint stress-associated GI leakage in live animals. This review article will focus on this model, including its mechanisms, clinical implications, and applications for studying restraint stress-associated GI injury. Recent findings from studies using this model will also be highlighted, along with their potential for diagnosis and treatment. The article aims to discuss about current research and provide recommendations for further study, ultimately improving our understanding of the link between stress and GI injury and improving patient outcomes.

Keywords: Apoptosis; Gastrointestinal injury; Inflammation; Restraint stresses; Tight junction.

Figure 1

Bidirectional communication between the gut and the brain. The diagram illustrates the bidirectional communication between the gut and the brain, which is influenced by various pathways such as the immune pathways, endocrine pathways, neural pathways, autonomic nervous system, enteric nervous system, hypothalamic–pituitary–adrenal axis, and vagus nerve

Figure 2

Experiment outline of the Evans blue-fed restraint stress mouse model. The experimental protocol for the Evans blue-fed restraint stress mouse model was adopted from previous studies[4748]. Mice were subjected to 9 h of restraint stress in a 50-mL plastic falcon tube with air holes. Blood samples were collected at 0, 5, 7, and 9 h, and Evans blue (1.2 g/kg) was fed to the mice before stress. Their blood plasma was isolated by collecting blood in an Eppendorf tube and mixing it with an equal proportion of anticoagulant citrate dextrose solution to prevent coagulation[545758]. The concentration of Evans blue in the plasma was measured using a spectrum analyzer

Figure 3

Restraint stress resulted in the development of anxiety-like behaviors in C57Bl/6J mice. Throughout the 20-h stress procedure, both the no stress and stress groups were deprived of access to food and water. After the termination of restraint stress, both the unstressed and stressed groups of mice were given access to food and water for a period of 2 h to restore their resources. Subsequently, the elevated plus maze (EPM) was conducted. Video recordings were captured using an iPhone Xs Max and later analyzed using ToxTrac_v2.98 software. Representative video tracking images captured during a 5-minute EPM are presented (a). A comparison was made between the control group (no stress) and the restraint stress group (stress) for open-arm traveled distance (b), and open-arm staying time (c). The number of samples used for analysis was 3 (n = 3). The statistical significance of the obtained results was examined using student's t-test. and *indicates statistical significance at P < 0.05, when compared to their respective no stress groups. All protocols for examining the experimental animals were approved by the Animal Care and Use Committee of Tzu Chi University, Hualien, Taiwan (approval ID: 111052)