[Defensin-5 and Matrilysin mRNA expression in the intestine of scalded rats and its relation to bacterial translocation].

OBJECTIVE

To investigate the effect of burn injury on the expression of rat defensin-5 (RD-5) and Matrilysin mRNA in the intestine of scalded rats and to determine its relation to bacterial translocation.

METHODS

Thirty-two Wistar rats were divided randomly into sham injury group (n=8) and burn group (n=24). Rats of the burn group were subjected to 30% total body surface area (TBSA) full-thickness scald injury. At 8, 24 and 72 hours after the injury, the animals (n=8 at each time point) were sacrificed and ileum was sampled for the determination of the expression of RD-5 mRNA and Matrilysin mRNA with reverse transcription-polymerase chain reaction (RT-PCR) technique. Cultures of mesenteric lymph nodes (MLN), liver, spleen and lung were carried out at 24 hours after the injury to assess the rate of bacterial translocation to visceral organs,and the morphological changes in ileal Paneth cells were observed.

RESULTS

The expression of RD-5 mRNA was significantly up-regulated at 8 hours when compared with control group. It was down-regulated sharply at 24 hours but was still higher than control group, and at 72 hours it was down-regulated to a level lower than control. On the contrary, the expression of Matrilysin mRNA was up-regulated continuously to 72 hours, and it was significantly higher than control. Bacterial translocation rate was significantly higher in rats of the burn group at 24 hours (58.3%) than in control group (8.3%, P<0.01), but there were no obvious morphological changes in ileal Paneth cells at the same time point.

CONCLUSION

The expressions of both RD-5 mRNA and Matrilysin Mrna are up-regulated in the early stage after the injury, but their time phases are different. The phenomenon might imply that there is a host protective response against bacterial translocation.