Inflammatory mediators in acute pancreatitis

Protective effects of edaravone against acute necrotizing pancreatitis in rats

AIM: To investigate whether edaravone has protective effects against acute necrotizing pancreatitis (ANP) in rats and to explore the possible mechanisms involved.

METHODS: Ninety male Spraque-Dawley rats were randomly and equally divided into sham operation group, ANP group and edaravone treatment group (EDA group). ANP was induced in rats of the ANP and EDA groups by retrograde injection of 1.5% deoxycholate. The EDA group was injected with edaravone (6 mg/kg) via the tail vein immediately after ANP induction. The rats were sacrificed 6, 12, and 24 h after the operation. Pathological changes in the pancreas were observed and graded. Serum levels of amylase, tumor necrosis factor-alpha (TNF-α), endothelin-1 (ET-1) and soluble intercellular adhesion molecule-1 (sICAM-1), as well as malonic dialdehyde (MDA) content and superoxide dismutase (T-SOD) activity in pancreatic tissue were measured.

RESULTS: Compared to the sham operation group, pancreatic pathological scores, serum levels of amylase, TNF-α, ET-1 and sICAM-1, and the contents of MDA in pancreatic tissue were significantly increased, and T-SOD activity in pancreatic tissue was significantly decreased in the ANP group. Compared to the ANP group, pancreatic pathological scores, serum levels of TNF-α (6 h: 109.6 ng/L ± 49.0 ng/L vs 190.2 ng/L ± 46.6 ng/L, 12 h: 405.4 ng/L ± 116.3 ng/L vs 559.7 ng/L ± 203.9 ng/L, 24 h: 415.4 ng/L ± 164.6 ng/L vs 648.7 ng/L ± 222.1 ng/L, all P < 0.05), ET-1 (6 h: 45.6 ng/L ± 13.5 ng/L vs 66.0 ng/L ± 16.0 ng/L, 12 h: 83.5 ng/L ± 15.4 ng/L vs 96.8 ng/L ± 23.0 ng/L, 24 h: 85.1 ng/L ± 25.8 ng/L vs 103.9 ng/L ± 28.9 ng/L, all P < 0.05), and sICAM-1 (6 h: 0.58 ng/L ± 0.13 ng/L vs 0.78 ng/L ± 0.14 ng/L, 12 h: 0.78 ng/L ± 0.10 ng/L vs 0.94 ng/L ± 0.12 ng/L, 24 h: 0.96 ng/L ± 0.16 ng/L vs 1.24 ng/L ± 0.30 ng/L, all P < 0.05), and the contents of MDA in pancreatic tissue (6 h: 4.22 nmol/mgprot ± 0.40 nmol/mgprot vs 8.79 nmol/mgprot ± 0.80 nmol/mgprot, 12 h: 5.90 nmol/mgprot ± 0.51 nmol/mgprot vs 12.30 nmol/mgprot ± 1.02 nmol/mgprot, 24 h: 9.10 nmol/mgprot ± 0.84 nmol/mgprot vs 17.88 nmol/mgprot ± 1.43 nmol/mgprot, all P < 0.05) were reduced, and T-SOD activity was increased (6 h: 88.6 U/mgprot ± 7.1 U/mgprot vs 68.8 U/mgprot ± 10.5 U/mgprot, 12 h: 77.6 U/mgprot ± 6.8 U/mgprot vs 46.0 U/mgprot ± 8.9 U/mgprot, 24 h: 45.5 U/mgprot± 5.3 U/mgprot vs 27.8 U/mgprot ± 4.3 U/mgprot, all P < 0.05) in the EDA group. No significant differences were observed in serum levels of amylase between the ANP and EDA groups.

CONCLUSION: Edaravone can eliminate the excessive generation of oxygen free radicals, down-regulate the expression of inflammatory cytokines, and reduce tissue injury in rats with ANP.

Role of neuropathic pain mechanisms in the pathogenesis of pain in chronic pancreatitis

Abdominal pain is a major clinical symptom in patients with chronic pancreatitis. Alleviation of abdominal pain is important in the treatment of chronic pancreatitis. More and more studies show that the pain in chronic pancreatitis is similar to neuropathic pain. In this article, we will review the role of neuropathic pain mechanisms in the pathogenesis of pain in chronic pancreatitis by describing the clinical features of the pain, peripheral sensitization, central sensitization and changes in electroencephalogram. Understanding of the mechanisms responsible for pain in chronic pancreatitis may have important implications for the treatment of the disease.