ABSTRACT
Objective To evaluate the expression of ?-defensin-2(BD-2) gene and protein with ventilator-associated pneumonia(VAP) in the old and grown rats.Methods Fifty-eight normal healthy Sprague-Dawley rats were divided into the old group(400～460 g,15～18 months,n=29) and grown group(280～320 g,4～6 months,n=29).Each rat received ventilation(VT=12 ml/kg) through tracheal tube for 24h and was challenged intra-tracheally with Pseudomonas aeruginosa(0.2 ml).The mRNA and protein levels of BD-2 were detected by RT-PCR and Western blot analysis respectively. Results Compared with the grown group,the rats had more severe interstitial pulmonary edema in the old group.There was no dominant difference in BD-2 mRNA and protein expression between the grown group and old group within 3 h,but BD-2 expressions in the grown group were significantly higher at 3 h,6 h,12 h,1 d,2 d and 3 d than those in the old group(P