Inflammation of Mesenteric Adipose Tissue Correlates with Intestinal Injury and Disease Severity in Rats with Severe Acute Pancreatitis.

Abstract

Visceral adipose tissue (VAT) is related to SAP prognosis. As a depot of VAT, mesenteric adipose tissue (MAT) resides between pancreas and gut, which might affect SAP and the secondary intestinal injury. To investigate the changes of MAT in SAP. 24 SD rats were randomly divided into four groups. 18 rats in SAP group were euthanized in time gradients (6h, 24h, and 48h after modeling) and the others in control group. Blood samples and tissues of pancreas, gut, and MAT were taken for analysis. Compared to the control group, SAP rats appeared MAT inflammation, presenting higher mRNA expression of TNF-α and IL-6 and lower IL-10, and histological changes after 6h of modeling, which became worse over time. Flow cytometry showed that B lymphocytes increased in MAT after 24h of SAP modeling and lasted up to 48h, earlier than the changes of T lymphocytes and macrophages. The intestinal barrier integrity was damaged after 6h of modeling, presenting lower mRNA and protein expression of ZO-1 and occludin, higher serum levels of LPS and DAO, with pathological changes, which gradually aggravated after 24h and 48h. SAP rats had higher serum levels of inflammatory indicators and revealed histological inflammation of pancreas, the severity of which increased with the passage of modeling time. MAT appeared inflammation in early-stage SAP, and became worse over time, with the same trend as the intestinal barrier injury and the severity of pancreatitis. B lymphocytes infiltrated early in MAT, which might promote the MAT inflammation.