[Role of platelet activating factor in the injury of intestinal immuno-barrier function in young rats].

OBJECTIVE

Gastrointestinal dysfunction is closely correlated with the destruction of intestinal barrier function induced by serious infection. Platelet activating factor (PAF) may induce intestinal injuries. This study aimed to investigate the effect of PAF on the injury of intestinal mucosal immuno-barrier function in young rats.

METHODS

Eighteen-day-old Wistar rats were randomized to lipopolysaccharide (LPS) (5 mg/kg), LPS plus PAF receptor antagonist and normal saline injection (Control). PAF receptor antagonist BN52021 5 mg/kg was administered before or 30 minutes after LPS injection (pretreatment or treatment). The ileum specimens (n=8) were harvested at 1.5, 3, 6, 24, 48 and 72 hrs after LPS injection. Double antibody-PEG radioimmunoassay was used to determine the secretory IgA (sIgA) content in intestinal mucosa. Hematoxylin and erosin staining was used for histological evaluation. The ratio of wet and dry weight (W/D) of ileum tissues was calculated.

RESULTS

Intestinal villi edema, capillary congestion, extension of the subepithelial lympho channel, and polymorphonuclear infiltration in enteric cavity were noted in the LPS group at 1.5, 3, 6 and 24 hrs after LPS injection. In the PAF receptor antagonist group only villi edema was found. The W/D ratio in the LPS group was significantly higher than that in the Control group at all time points, but it was slightly reduced by the PAF receptor antagonist pretreatment or treatment. The sIgA content was obviously decreased after 1.5, 3, 6, 24 and 48 hrs of LPS challenge compared with that in the Control group (P < 0.01). It reached to a nadir at 6 hrs (0.15 +/- 0.04 microg/mL). The level of sIgA in the PAF receptor antagonist group was higher than that in the LPS group at each time point. There was no statistical difference in the sIgA level between the PAF receptor pretreatment and treatment groups.

CONCLUSIONS

PAF plays roles in the injury of intestinal immuno-barrier function. Preventive and remedial use of PAF receptor antagonist BN52021 may relieve intestinal injury.