Review: Effect of Gut Microbiota and Its Metabolite SCFAs on Radiation-Induced Intestinal Injury

Abstract

Gut microbiota is regarded as the second human genome and forgotten organ, which is symbiotic with the human host and cannot live and exist alone. The gut microbiota performs multiple physiological functions and plays a pivotal role in host health and intestinal homeostasis. However, the gut microbiota can always be affected by various factors and among them, it is radiotherapy that results in gut microbiota 12dysbiosis and it is often embodied in a decrease in the abundance and diversity of gut microbiota, an increase in harmful bacteria and a decrease in beneficial bacteria, thereby affecting many disease states, especially intestine diseases. Furthermore, gut microbiota can produce a variety of metabolites, among which short-chain fatty acids (SCFAs) are one of the most abundant and important metabolites. More importantly, SCFAs can be identified as second messengers to promote signal transduction and affect the occurrence and development of diseases. Radiotherapy can lead to the alterations of SCFAs-producing bacteria and cause changes in SCFAs, which is associated with a variety of diseases such as radiation-induced intestinal injury. However, the specific mechanism of its occurrence is not yet clear. Therefore, this review intends to emphasize the alterations of gut microbiota after radiotherapy and highlight the alterations of SCFAs-producing bacteria and SCFAs to explore the mechanisms of radiation-induced intestinal injury from the perspective of gut microbiota and its metabolite SCFAs.

The radio-protective effects of (-)- Epigallocatechin-3-gallate (EGCG): regulating macrophage function in radiation-induced intestinal injury

“…Currently, the pathogenesis of RIII remains unknown, but it is believed that the combined effects of epithelial injury, vascular changes, microbial and immune factors lead to severe radiation enteropathy (Hauer-Jensen et al, 2014; Li et al, 2021). The gut microbiota plays an important role in maintaining intestinal barrier function, regulating immune homeostasis and protecting intestinal repair mechanisms (Ahlawat et al, 2021; Gasaly et al, 2021; Touchefeu et al, 2014).…”

“…There were a large number of TUNEL + cells in the crypts and villi in WAI group compared to the CON group, and EGCG+WAI group significantly decreased the apoptosis levels in the small intestine (Figure 3f). Alkaline phosphatase (ALP) is an endogenous enzyme and plays an important role in maintaining the integrity of intestinal epithelial cells (He et al, 2021;Sheng et al, 2021). At 3.5 days after WAI, ALP was lost from the jejunal (Figure 3g), the permeability of epithelial cells increased, causing increasingly expression of inflammatory factors (Figure 3h-j) (Lallès, 2019).…”

Marine Chitooligosaccharide Alters Intestinal Flora Structure and Regulates Hepatic Inflammatory Response to Influence Nonalcoholic Fatty Liver Disease

“…Acetic acid accounts for the highest proportion of short-chain fatty acids produced by intestinal bacteria. It can adjust the pH value of the intestinal tract to allow beneficial bacteria to survive, prevent harmful bacteria, and help maintain the stability of the intestinal environment [27]. Furthermore, studies have confirmed that SCFAs have important research significance for NAFLD [28].…”

Alterations in Intestinal Antioxidant and Immune Function and Cecal Microbiota of Laying Hens Fed on Coated Sodium Butyrate Supplemented Diets

“…There are multitudes of evidence revealing that a close correlation exists between intestinal microbes and the productive performance of poultry [ 13 , 14 ]. Short-chain fatty acids (SCFAs) are deemed as one of the richest metabolites of intestinal microorganisms and effectively regulate the microbial balance and maintain the stability of the internal environment [ 15 ]. Nevertheless, there remain rare reports on the effects of sodium butyrate supplementation on the cecal microbiota and metabolites of laying hens.…”