Objective    To determine the effects of janus kinase/signal transducer and activator of transcription on the synthesis of inducible nitric oxide synthase (iNOS) and nitric oxide (NO) in infectious shock rats.     Methods    Forty-eight male Wistar rats were randomly divided into normal control

sham operation group

cecal ligation puncture (CLP) group

and inhibitor of JAK (AG490) treatment group. CLP group and AG490 group were established into the sepsis model induced by CLP

and at 2

6

24 h after CLP

the rats were sacrificed. The pulmonary

vascular tissues and serum samples of all rats were harvested to determine iNOS mRNA expression levels by reverse transcription polymerase chain reaction (RT-PCR) and NO content respectively. Meanwhile

the mean arterial pressure (MAP) and pulse were monitored.     Results    No notable difference was detected in all parameters between sham operation group and normal control. Compared with normal control

iNOS mRNA and NO levels in pulmonary

vascular tissues and serum at 2

6 and 24 h following CLP significantly elevated respectively

and MAP fell notably and pulse increased (P0.05 or 0.01). AG490 treatment decreased iNOS mRNA and NO levels markedly at 2 or 6 h after CLP

meanwhile MAP and pulse deteriorated by sepsis were also ameliorated (P0.05 or 0.01).     Conclusion    Inhibiting the activation of JAK/STAT pathway can reduce tissues and serum iNOS mRNA and NO expressions in infectious shock rats and can ameliorate the circulatory function deteriorated by sepsis.