Ellagic acid mitigates rotavirus-induced intestinal injury via bidirectional "immune-microbiota" regulatory effect.

INTRODUCTION: Rotavirus (RV) is a major cause of childhood gastroenteritis, leading to intestinal damage, inflammation, and gut microbiota dysbiosis. This study investigated whether ellagic acid (EA), a natural polyphenol, can alleviate RV-induced intestinal injury by modulating both host immunity and the gut microbiota. METHODS: In this study, RV was used to infect BALB/c suckling mouse models to explore whether ellagic acid could alleviate intestinal damage following rotavirus infection through bidirectional regulation of "immunity and microbiota". The viral load of RV, the expression levels of IL-1β, IL-6, and TNF-α mRNA were detected by qPCR. The pathological changes in the jejunal tissue were observed by hematoxylin and eosin (H&E) staining. The expression of JAM1, ZO-1, and Claudin-4 proteins in jejunal tissue were detected by immunohistochemistry (IHC). The expressions of TLR4, MYD88, IκBα, and P-P65 proteins in jejunal tissues were detected by WB. 16S rDNA gene sequencing was employed to detect the structural changes of the microbiota in feces, and qPCR was used to detect the colonization of Lactobacillus johnsonii, Lactobacillus reuteri, and Lactobacillus gasseri in jejunal tissues. RESULTS: The qPCR results revealed that ellagic acid could significantly (P < 0.001) reduce the viral load as well as the mRNA expression levels of IL-1β, IL-6, and TNF-α in RV-infected BALB/c suckling mice. The results of H&E staining demonstrated that ellagic acid could alleviate villus rupture and vacuolation lesions induced by RV and significantly (P < 0.05) alleviate intestinal villus shortening and crypt deepening caused by RV. The IHC results showed that ellagic acid could significantly increase the expression of tight junction proteins JAM1, ZO-1, and Claudin-4 in RV-infected BALB/c neonatal mice. The WB results showed that ellagic acid significantly (P< 0.001) inhibited the expression of the TLR4/NF-κB signaling pathway. The results of 16S rDNA gene sequencing showed that ellagic acid could lead to a significant (P < 0.05) increase in the abundance of intestinal Lactobacillus bacteria (Lactobacillus johnsonii, Lactobacillus reuteri, Lactobacillus gasseri, etc.) in RV-infected BALB/c suckling mice. Ellagic acid can also significantly promote the colonization of Lactobacillus johnsonii, Lactobacillus reuteri, and Lactobacillus gasseriin the jejunum. DISCUSSION: Ellagic acid can alleviate intestinal damage following rotavirus infection through bidirectional regulation of "immunity and microbiota", providing a theoretical foundation and innovative concepts for the research and development of EA as an anti-RV drug.