Objective      To determine the effect of telmisartan on ventilator-induced lung injury (VILI) in rats.       Methods      Forty healthy male SD rats were equally divided into four groups in random (A

B

C and D groups

n=10). Group A serve

d as control group

in which rats did not receive ventilation. Groups B

C and D received large-tide volume ventilation

but only rats from groups C and D received intraperitoneal injection with telmisartan solution (2.5 and 5 mg/kg respectively. Telmisartan was dissolved in PBS) in 30 min before ventilation. Equal amount of PBS solution was given to rats in groups A and B. A rat model of VILI was reproduced by volume-controlled mechanical ventilation with large tide volume （Vt=40 ml/kg for 2 h）. Hemodynamic parameters and arterial blood gases of all the rats in the 4 groups were measured throughout the study period. After maintaining ventilation for 2 h

all rats were sacrificed and specimens of lung tissues and bronchoalveolar lavage fluid (BALF) were harvested. Lung pathological changes were observed by microscopy

and Smith score was estimated. The protein levels of peroxisome proliferator activated receptor-γ (PPAR-γ) and AngⅡ1 receptor (AT1R) in lung tissues were assayed with immunohistochemistry staining. Lung myeloperoxidase (MPO) activity and wet-dry weight ratio (W/D) were measured. The levels of tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8) in BALF were measured by enzyme-linked immunosorbent assay (ELISA)．       Results      Mean pH values in arterial blood from groups B

C and D tended to be higher than the base line value during the ventilation

while mean arterial pressure (MAP)

mean partial pressure of carbon dioxide in arterial blood [p(CO

2

)

]

and mean partial pressure of oxygen in arterial blood [p(O

2

)

]

were lower than baseline in these groups. MAP in groups C and D was significantly lower than in group B after 2 hours’ ventilation（P＜0.05）. Smith score

mean MPO activity

mean W/D ratio

concentration of TNF-α and IL-8 in groups B

C and D were significantly higher than in group A (P＜0.05

P＜0.01). The protein expression of PPAR-γ in groups of B

C and D was significantly lower than in group A（P＜0.05

P＜0.01）

but that of AT1R was significantly higher than group

A（P＜0.05

P＜0.01）. Besides the protein expression of PPAR-γ

the rest parameters

such as Smith score

mean MPO activity

mean W/D ratio

protein expression of AT1R

and the concentrations of TNF-α and IL-8 in groups C and D were significantly lower than in group B（P＜0.05

P＜0.01）.What’s more

Smith score

concentration of TNF-α and IL-8 and protein expression of AT1R in groups of D were significantly lower than group C（P＜0.05）

and the protein expression of PPAR-γ was significantly higher in group D（P＜0.05）.       Conclusion      These results suggest that telmisartan attenuates VILI probably through regulating PPAR-γ and AT1R

decreasing the productions of the inflammation factors TNF-α and IL-8

and then slowing down the inflammatory response and lung injury in the lung issue.