Effect of patchouli alcohol on Helicobacter pylori-induced neutrophil recruitment and activation

Neutrophil infiltration typically occurs in Helicobacter pylori (H. pylori)-induced acute gastritis; however, this immune response fails to eradicate H. pylori in vivo. Moreover, reactive oxygen species (ROS), which are generated by neutrophils, cause severe damage to gastric mucosa. Patchouli alcohol (PA) has been reported to have effective anti-oxidative and anti-H. pylori activities, and we investigated its effects on H. pylori-induced neutrophil recruitment and activation in this research. In neutrophil recruitment experiment, H. pylori was injected into rat air pouch to explore the effects of PA (10, 20 and 40 mg/kg) on acute inflammatory response. The results revealed that PA significantly reduced the weight of exudate and the number of neutrophils in the air pouch. Meanwhile, remarkable decrements in TNF-α and IL-8 levels in exudates were observed. In neutrophil activation experiment, rat neutrophils were isolated and activated by using 50 μg/mL H. pylori water-soluble surface protein with or without the treatment of PA (5, 10 or 20 μmol/L). Results indicated that PA not only significantly inhibited the production of ROS, but also reduced the gene and protein expressions of p22/p47-phoxes, and the binding of p22/p47-phoxes. Furthermore, the influence of PA on the neutrophil activation genes of H. pylori (h-nap and sabA) was investigated, and the results showed that expressions of h-nap and sabA were remarkably decreased after PA treatment. In conclusion, PA reduced the recruitment and activation of neutrophils induced by H. pylori, as shown by its inhibition of pro-inflammatory factor generation, p22/p47-phoxes function and H. pylori neutrophil activation-related gene expression.