Background:

Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway plays an important role in sepsis, transducing a multitude of inflammatory signals. To date, knowledge of JAK/STAT pathway in sepsis is limited. This study was to investigate the potential role of JAK/STAT pathway in mediating multiple organ damage and mortality in septic rats. Our data showed that inhibition of JAK2/STAT3 attenuated cecal ligation and puncture-induced multiple organ damage and mortality in 48 hours in rats.

Methods:

A total of 98 male Wistar rats were randomly divided into 4 groups as follows:(1) normal control group (n= 10);(2) cecal ligation and puncture (CLP) group (n= 40), which was further divided into 2, 6, 24, 48-hour post-CLP groups;(3) AG490 (8.0 mg/kg, Calbiochem, La Jolla, CA) treatment group (n= 24), which was further divided into 2, 6, 24, 48-hour post-CLP groups;(4) rapamycin (0.4 mg/kg, Calbiochem, Calbiochem, La Jolla, CA) treatment group (n= 24), which was further divided into 2, 6, 24, 48-hour post-CLP groups; CLP was performed to induce experimental sepsis. AG490 (8 mg/kg) or rapamycin (0.4 mg/kg) was injected subcutaneously 0.5 hour before CLP in respective group. Animals were killed at destined time after CLP (not including the death rate observation group), and specimens of serum, liver, and lungs were harvested and stored in liquid nitrogen for subsequent analyses. In an additional experiment, 88 animals were randomly divided into three groups to compare the survival rate, including CLP group (n= 40), AG490 treatment group (8 mg/kg, n= 24), and rapamycin treatment group (0.4 mg/kg, n= 24). Mortality of rats in each group was recorded up to 48 hours after the procedure.

Results:

After CLP challenge, myeloperoxidase (MPO), aspartate transaminase, and alanine aminotransferase levels, as well as activation of JAK2 and STAT3, were markedly increased. Administration of AG490 or rapamycin significantly decreased activation of JAK2 and STAT3, as well as high mobility group box-1 protein, MPO, alanine aminotransferase levels (p< 0.05 or p< 0.01). In addition, treatment with AG490 or rapamycin significantly improved the 48-hour survival rate from 37.5%(15 of 40) to 66.7%(16 of 24) and 70.8%(17 of 24), respectively (both p< 0.05).

Conclusion:

JAK2/STAT3 pathway might play a role in the development of multiple organ damage in septic rats, which suggested a potential strategy to control sepsis.