Journal of Jilin University(Medicine Edition) ›› 2021, Vol. 47 ›› Issue (1): 158-167.doi: 10.13481/j.1671-587x.20210122

• Research in basic medicine • Previous Articles     Next Articles

Inhibitory effect of baicalin on inflammation in rats with spinal cord injury by regulating macrophage M2 polarization

Dayong XU(),Yunpeng LI,Jingmei WEI,Ruyin LIU   

  1. Department of Spine Surgery,Henan Provincial Hospital of Traditional Chinese Medicine,Zhengzhou 450002,China
  • Received:2020-07-17 Online:2021-01-28 Published:2021-01-27
  • Contact: Dayong XU E-mail:albertgates@sina.com

Abstract: Objective

To explore the protective effect of baicalin on the spinal cord injury (SCI) in the rats, and to clarify its mechanism.

Methods

The SCI models of rats were established by modified Allen’s method in vivo. Fifty healthy SD rats were randomly divided into sham operation group (given normal saline), model group (modeling, given normal saline), baicalin group (modeling, given 200 mg·kg-1 baicalin), baicalin+ DMSO group (modeling, given 200 mg·kg-1 baicalin and 0.2% DMSO) and baicalin +AS1517499 (STAT6 pathway inhibitor) group (modeling, given 200 mg·kg-1 baicalin and 10 mg·kg-1 AS1517499)(n=10). After the models were successfully established, the spinal cord motor function of rats was evaluated by using the Basso-Beattie-Bresnahan (BBB) method. In vitro, 2.5 μg·L-1 lipopolysaccharide (LPS) and 0.125 μg·L-1 interferon-γ (IFN-γ) were used to induce M1 polarization of macrophages (RAW264.7), and 10 μg·L-1 interleukin-4 (IL-4) was used to induce M2 polarization of macrophages. The RAW264.7 cells were divided into control group, M1 type polarization group, M2 type polarization group,M1 type polarization+ baicalin group, M2 type polarization+ baicalin group, M1 type polarization+baicalin+AS1517499 group,and M1 type polarization+baicalin+DMSO group. ELISA assay was used to detect the levels of inflammatory factors interleukin-12(IL-12),tumor necrosis factor-α(TNF-α),interleukin-4( IL-4) and interleukin-10(IL-10) in the spinal cord tissue and RAW264.7 cells of the rats; Western blotting method was used to detect the expression levels of M1 type macrophage marker proteins inducible nitric oxide synthase(iNOS)and chemokine-5( CCL-5), M2 type macrophage marker proteins arginase 1(Arg1)and mannose receptor C1(MRC1) and Janus kinase 1/signal transducer and activator of transcription 6(JAK1/STAT6) pathway related proteins in spinal cord tissue and RAW264.7 cells of the rats.

Results

In vivo experiments, compared with model group, the BBB score of the rats in baicalin group was significantly increased (P<0.05), the levels of IL-12 and TNF-α and the expression levels of iNOS,CCL-5,and p-STAT1 proteins in spinal cord tissue were significantly reduced (P<0.05), and the levels of IL-4 and IL-10 and the expression levels of Arg1, MRC1, p-JAK1 and p-STAT6 proteins were significantly increased (P<0.05). Compared with baicalin+DMSO group, the levels of IL-12 and TNF-α and the expression levels of iNOS, CCL-5 and p-STAT1 proteins in the spinal cord tissue of the rats in baicalin+AS1517499 group were significantly increased (P<0.01), and the levels of IL-4 and IL-10 and the expression levels of Arg1, MRC1,and p-STAT6 proteins were significantly reduced (P<0.01). In vitro experiments, compared with M1 type polarization group, the expression levels of iNOS, CCL-5 and p-STAT1 proteins in the RAW264.7 cells in M1 type polarization + baicalin group were significantly reduced (P<0.05),and the expression levels of p-JAK1 and p-STAT6 proeins were significantly increased(P<0.05). Compared with M2 type polarization group, the expression levels of Arg1 and MRC1 in M2 type polarization+baicalin group were significantly increased (P<0.05). Compared with M1 type polarization+baicalin+DMSO group, the levels of IL-12 and TNF-α in the RAW264.7 cells in M1 type polarization+baicalin+AS1517499 group were significantly increased (P<0.05), and the levels of IL-12 and TNF-α were significantly decreased (P<0.05), the expression levels of p-STAT6, Arg1 and MRC1 proteins were significantly reduced (P<0.05), and the expression levels of iNOS and CCL-5 proteins were significantly increased(P<0.05).

Conclusion

Baicalin could activate the JAK1/STAT6 pathway and inhibit the inflammatory process of SCI rats by promoting M2 polarization of macrophages.

Key words: spinal cord injury, baicalin, inflammatory response, Janus kinase 1, signal transducer and activator of transcription 6, signal pathway

CLC Number: 

  • R285.5