Influence of dexamethasone on mesenteric lymph node of rats with severe acute pancreatitis

Abstract

Aim: To study the influence and mechanisms of dexamethasone on mesenteric lymph node of rats with severe acute pancreatitis (SAP).

Methods: The SAP rats were assigned to model, treated or sham-operated groups. The mortality, pathological changes of mesenteric lymph nodes, expression levels of NF-kappa B, P-selectin, Bax, Bcl-2 and caspase-3 protein and changes in apoptotic indexes in lymph nodes were observed at 3, 6 and 12 h after operation. The blood levels of endotoxin, superoxide dismutase (SOD), malondialdehyde (MDA), and endothelin-1 (ET-1) in blood were determined.

Results: SOD content, expression of Bax protein and apoptotic index were significantly higher in the treated group than in the model group at different time points (P < 0.05 or P < 0.01). Other blood-detecting indexes and histopathological scores of mesenteric lymph nodes were lower in the treated than in the model group (P < 0.05, P < 0.01 or P < 0.01). NF-kappa B protein expression was negative in all groups. Comparing P-selectin and caspase-3 expression levels among all three groups, there was no marked difference between the model and treated group.

Conclusion: Dexamethasone can protect mesenteric lymph nodes. The mechanism may be by reducing the content of inflammatory mediators in the blood and inducing lymphocyte apoptosis.

Figure 1

Tissue microarrays of mesenteric lymph nodes were prepared and stained for mmunohistochemistry (× 200). (A) NF-κB expression in the treated group (6 h); (B) Bax protein expression in the sham-operated group (3 h); (C) Bax protein expression in the treated group (12 h); (D) Bcl-2 protein expression in the treated group (3 h).

Figure 2

TUNEL staining, showing the pathological changes in the mesenteric lymph nodes (× 400). (A) In the sham-operated group (6 h), there were no apoptotic cells; (B) In the model group (12 h), several apoptotic cells appeared; (C) treated group (6 h); (D) apoptotic cells were increased in the treated group (12 h).