Anti-inflammative effect of glycyrrhizin on rat thermal injury via inhibition of high-mobility group box 1 protein.
AIM
Glycyrrhizin (Gly) has been reported as an inhibitor of extracellular HMGB1 (high-mobility group box 1 protein) cytokine's activity, and protects spinal cord, liver, heart and brain against ischemia-reperfusion-induced injury in rats. The purpose of this study was to investigate the protective effect of Gly in rat skin thermal injury model and to elucidate the underlying mechanisms.


METHODS
Twenty-four male Sprague-Dawley rats (200-250g) were randomly divided into control group, vehicle-treated and Gly-treated burn groups, each group contained eight animals. In the latter two groups, rats were subjected to 30% TBSA (Total Body Surface Area) full-thickness scald injury. In Gly-treated burn group, glycyrrhizin (60mg/kg) was administered intraperitoneally immediately after and at 24th hour burn; in vehicle-treated burn group, Ringer's solution (4ml/kg, as a vehicle) was administered intraperitoneally immediately after and at 24th hour burn. The animals were sacrificed at 48h after injury. Aortic blood samples were obtained to detect tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) with ELISA (Enzyme-Linked Immuno Sorbent Assay) kits. Lung, liver and kidney tissue samples were collected to determine the expression of HMGB1 mRNA and protein. HMGB1 mRNA level was semiquantitatively measured by Real-Time PCR using β-actin as an internal standard, and protein expression of HMGBI was determined by Western blot.


RESULTS
Severe skin scald injury caused a significant increase in plasma TNF-α and IL-1β versus the control group (P<0.001) in 48h after burns. Intraperitoneal administration of Gly (60mg/kg) significantly reduced the levels of serum TNF-α and IL-1β (P<0.01). Gly treatment reduced these biochemical indices accompanied by lower level of HMGB1 protein (P<0.05) and mRNA expression (P<0.01).


CONCLUSION
These results demonstrate that Gly possesses an anti-inflammation effect to protect the remote organs from burn-induced injury.
['Shen|Liangyun|L|', 'Cui|Ziwei|Z|', 'Lin|Yue|Y|', 'Wang|Shuqin|S|', 'Zheng|Dongfeng|D|', 'Tan|Qian|Q|']
D000199:Actins D000818:Animals D000893:Anti-Inflammatory Agents D015153:Blotting, Western D002056:Burns D004195:Disease Models, Animal D019695:Glycyrrhizic Acid D024243:HMGB1 Protein D007249:Inflammation D007274:Injections, Intraperitoneal D053583:Interleukin-1beta D007668:Kidney D008099:Liver D008168:Lung D008297:Male D012333:RNA, Messenger D051381:Rats D017207:Rats, Sprague-Dawley D060888:Real-Time Polymerase Chain Reaction D014409:Tumor Necrosis Factor-alpha
Glycyrrhizin HMGB1 Burn Inflammation