Effect of glycyrrhizin on traumatic brain injury in rats and its mechanism

• Published in: Chinese journal of traumatology Vol. 17; no. 1; pp. 1 - 7
• Main Authors: Xiangjin, Gu, Jin, Xu, Banyou, Ma, Gong, Chen, Peiyuan, Gu, Dong, Wei, Weixing, Hu
• Format: Journal Article
• Language: English
• Published: China Elsevier B.V 01.02.2014; Department of Neurosurgery, Jiangning Hospital Affiliated to Nanjing Medical University, Nanjing 211100, China%Department of Neurosurgery, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China; Elsevier
• Subjects: Animals; Brain injuries; Brain Injuries - drug therapy; DNA结合活性; Glycyrrhizic acid; Glycyrrhizic Acid - pharmacology; Glycyrrhizic Acid - therapeutic use; HMGB1 protein; HMGB1 Protein - metabolism; Male; Neuroprotective agents; Neuroprotective Agents - therapeutic use; RAGE; Rats; Rats, Sprague-Dawley; SD大鼠; Toll样受体4; 创伤性脑损伤; 甘草甜素; 神经保护作用; 脑组织含水量; Glycyrrhizic acid; Neuroprotective agents; HMGB1 protein; Brain injuries
• DOI: 10.3760/cma.j.issn.1008-1275.2014.01.001
• ISSN: 1008-1275

Objective： To investigate the neuropro- tective effects of glycyrrhizin （Gly） as well as its effect on expression of high-mobility group box 1 （HMGB1） in rats after traumatic brain injury （TBI）. Methods： Male Sprague-Dawley rats were randomly divided into three groups： sham group, TBI group, and TBI＋Gly group （n=36 per group）. Rat TBI model was made by using the modified Feeney＇s method. In TBI＋Gly group, Gly was administered intravenously at a dosage of l0 mg/kg 30 min after TBI. At 24 h after TBI, motor function and brain water content were evaluated. Meanwhile, HMGB 1/HMGB 1 receptors including toll-like receptor 4 （TLR4） and receptor for advanced glycation end products （RAGE）/nuclear fac- tor-κ B（NF- κ B） signaling pathway and inflammatory cytokines in the injured brain tissues were detected using quantitative real-time polymerase chain reaction, western blot, electrophoretic mobility shift assay and enzyme-linked immunosorbent assay. Furthermore, HMGB l, RAGE and TLR4 immunohistochemistry and apoptosis were analyzed. Results： Beam walking performance impairment and brain edema were significantly reduced in TBI＋Gly group compared with TBI group; meanwhile, the over-expressions of HMGB 1PHMGB 1 receptors （TLR4 and RAGE）/NF- κB DNA-binding activity and inflammatory cytokines were inhibited. The percentages of HMGB 1, RAGE and TLR4- positive cells and apoptotic cells were respectively 58.37%±5.06%, 54.15%±4.65%, 65.50%± 4.83%, 52.02%±4.63% in TBI group and 39.99%±4.99%, 34.87%±5.02%, 43.33%±4.54%, 37.84%±5.16% in TBI＋Gly group （all P〈0.01 compared with TBI group）. Conclusion： Gly can reduce secondary brain injury and improve outcomes in rat following TBI by down-regula- tion of HMGB 1/HMGB 1 receptors （TLR4 and RAGE）/NF- κB - mediated inflammatory responses in the injured rat brain.