X. Cheng1, Z. Liu1, B. Liu1, Y. Li1, H. B. Alam1 1University Of Michigan,General Surgery,Ann Arbor, MI, USA
Introduction: Hemmorrhagic shock (HS) followed by a subsequent infection (“second hit”) is highly lethal. We have previously demonstrated that treatment with valproic acid, a pan histone deacetylase (HDAC) inhibitor, improves survival in a rodent “two-hit” model. In the present study, our aim was to determine whether selective inhibition of histone deacetylase 6 with Tubstatin A (Tub A) could prolong survival in a 2-hit model.
Methods: C57Bl/6J mice were subjected to HS (40% blood loss) and then randomly divided into 2 groups (n=13/group): The treatment group was injected (intraperitoneal) with Tub A (70 mg/kg) dissolved in 1 µl/g of dimethyl sulfoxide (DMSO), whereas the vehicle (Veh) group was given 1 µl/g of DMSO. After 24 h, all mice were subjected to cecal ligation and puncture (CLP) followed by a second dose of Tub A or DMSO. Survival was monitored for 10 days. In a parallel study, peritoneal irrigation fluid and liver tissues were collected at 3h after CLP. Enzyme-linked immunosorbent assay was performed to determine the myeloperoxidase (MPO) activity (marker of neutrophil activation) and TNF-α and IL-6 concentrations in the peritoneal irrigation fluid, whereas real-time PCR was performed to measure the relative mRNA levels of TNF-α and IL-6 in the liver tissue.
Results: Tub A administration significantly improved survival compared to the control (69.2% vs 15.4%, p<0.0074) (Figure). In addition, Tub A significantly suppressed MPO activity (169.9±8.4 ng/ml vs 70.4±17.4ng/ml; p=0.0001), and inhibited levels of cytokine TNF-α and IL-6 in the peritoneal fluid (TNF-α: 105.7± 4.7 pg/ml vs 7.4±2.4 pg/ml; IL-6: 907.4±2.3 pg/ml vs 483.6 ±1.6 pg/ml; p=0.0001) compared to the vehicle control. Meanwhile, the hepatic gene expression of these cytokines was significantly lower (TNF-α: 18.9±7.8 vs 0.92±0.25; IL-6: 43.3±5.8 vs 8.3±3.4; p=0.0001) in the Tub A treated animals.
Conclusion: Tub A treatment significantly improves survival, attenuates inflammation and down regulates the gene expression and protein levels of TNF-α and IL-6 in a rodent two-hit model.
