Protective Effects of Calcitonin Gene-Related Peptide-Mediated p38 Mitogen-Activated Protein Kinase Pathway on Severe Acute Pancreatitis in Rats.

Abstract

Calcitonin gene-related peptide (CGRP) has antioxidant and anti-inflammatory activities on the pathological damage of acute pancreatitis. However, its molecular mechanism on severe acute pancreatitis (SAP) remains unknown. To evaluate the influence of CGRP-mediated p38MAPK signaling pathway in rats with SAP. SD rats were randomly divided into Sham group, SAP group, CGRP group (SAP rats injected with CGRP), SB203580 group (rats injected with p38MAPK pathway inhibitor SB203580), and CGRP8-37 group (SAP rats injected with CGRP8-37). Serum amylase and lipase activities were determined. Histopathological observations were evaluated, and the expression of inflammatory cytokines and oxidative stress-related indexes were measured. Compared with Sham group, SAP rats were increased in the activities of serum amylase and lipase, the pathologic assessment of pancreatic tissue, the levels of TNF-α, IL-1β, IL-6, and IL-8, the content of MDA and MPO, and the expressions of CGRP, and p-p38MAPK protein, but they were decreased in SOD activity and GSH content. The above alterations were aggravated in the CGRP8-37 group when compared with SAP group. Besides, in comparison with SAP group, rats in the CGRP and SB203580 groups presented a reduction in the activities of serum amylase and lipase, the levels of inflammatory cytokines, the content of MDA and MPO, and the expressions of p-p38MAPK protein, while showed an elevation in SOD activity and GSH content. Pretreatment with CGRP alleviated oxidative stress and inflammatory response of SAP rats possibly by suppressing the activity of p38MAPK pathway, and thereby postponing the disease progression.