Background Vascular hyporeactivity, which occurs in the terminal stage of hemorrhagic shock, is believed to be critical for treating hemorrhagic shock. The present study was designed to examine whether the CB1 cannabinoid receptor （CB1 R） was involved in the development of vascular hyporeactivity in rats suffering from hemorrhagic shock. Methods Sixteen animals were randomly divided into two groups （n=8 in each group）： sham-operated （Sham） and hemorrhagic shock （HS） groups. Hemorrhagic shock was induced by bleeding. The mean arterial pressure （MAP） was reduced to and stabilized at （25±5） mmHg for 2 hours. The vascular reactivity was determined by the response of MAP to norepinephrine （NE）. In later experiments another twelve animals were used in which the changes of CB1R mRNA and protein in aorta and superior mesenteric artery （SMA） were analyzed by RT-PCR and Western blotting. In addition, we investigated the effects of a CB1R antagonist on the vascular hyporeactivity and survival rates in rats with hemorrhagic shock. Survival rates were analyzed by the Fisher＇s exact probability test. The MAP response was analyzed by one-way analysis of variance （ANOVA）. Results Vascular hyporeactivity developed in all animals suffering from hemorrhagic shock. The expression of CBIR mRNA and protein in aorta and 2-3 branches of the SMA were significantly increased in the HS group after the development of vascular hyporeactivity when compared to those in Sham group. When SR141716A or AM251 was administered, the MAP response to NE was （41.75±4.08） mmHg or （44.78±1.80） mmHg respectively, which was higher than that in saline groups with （4.31±0.36） mmHg （P 〈0.01）. We also showed an increased 4-hour survival rate in the SR141716A or AM251-treated group with 20% or 30%, but with a statistically significant difference present between the AM251-treated and saline groups （P 〈0.05）. Conclusions CBIR is involved in vascular hyporeactivity resulting from hemorrhagic shock
Background Sepsis is a leading cause of death in the intensive care units. The late inflammatory cytokine, high-mobility group box 1 （HMGB1）, plays a critical role in sepsis. In the present study, we investigated the association between the serum HMGB1 levels and the severity of organ injury in the lipopolysaccharide-induced sepsis in rats. Methods To produce an animal model of sepsis with different degree of organ injury, animals were treated with three different doses of lipopolysaccharide （4, 8 and 16 mg/kg）, and the animals in control group were treated with the same volume of the vehicle （saline）. The levels of serum HMGB1 were measured at 0, 2, 4, 8, 16, 24, 32 and 48 hours after lipopolysaccharide （LPS） or vehicle injection, meanwhile the biochemical and histopathological indicators for the severity of organ injury were assessed. Results The level of HMGB1 had a positive, high correlation with the abnormal changes of serum cardiac troponin I, alanine aminotransferase, aspartate aminotransferase, creatinine and blood urea nitrogen, as well as the pathologic scores of heart, lung, liver and kidney. Conclusions The level of serum HMGB1 is highly correlated with the severity of sepsis in rats, suggesting that HMGB1 could serve as a valuable adjunct in the diagnosis and management of sepsis.
