Background: IL-12 inhibition of the endothelial cell functions and angiogenesis is mediated by the cross-talk between the lymphocyte and the endothelial cells, which plays a key role in inhibiting the process of angiogenesis in the eyeballs and in malignant tumors.
Methods: We established the intracerebral hemorrhage (ICH) rat model, and IL-12 receptor beta monoclonal antibody was injected into the ICH rats. Western blot, immunofluorescence and RT-qPCR were used to detect the gene expression. Brain water content, EB staining, Garcia test, Beam walking test and wire hanging test were used to assess the injury of brain in ICH rats.
Results: IL-12 gene was significantly increase in hematoma border tissue of ICH rats, and IL-12 protein mainly localized in monocytes. Anti-IL-12 treatment with IL-12 monoclonal antibodies could not only significantly decrease the brain water content and EB content in brain tissues of ICH rats, but also significantly increase the score of the Garcia, Beam balance and the Wire hanging test in ICH rats. Moreover, anti-IL-12 treatment significantly decrease the expression of pro-inflammatory gene, inflammatory gene, p-JAK2/JAK2 and p-STAT4/STAT4 protein, but significantly increase the expression anti-inflammatory gene and CD31 protein, and M2 macrophage ratio in hematoma border tissues of ICH rats. In vitro, rmIL-12 inhibited the tube formation of brain microvascular endothelial cells (BMVES) in BMVES and bone marrow-derived monocytes (BMDM) co-culture systems, but not work in a separately cultured BMVES system. In addition, Fedratinib not only reduced p-JAK2/JAK2 and p-STAT4/STAT4 protein expression in BMDM after treating with b-FGF and rmIL-12, but also significantly increased the tube formation of BMVES in BMVES and BMDM co-culture systems after treating with b-FGF and rmIL-12.
Conclusion: Blockade of IL-12 receptor attenuated brain injury after ICH in rat by promoting angiogenesis, and the mechanism might be related to blocking IL-12 could inhibit M2 cell activation via the JAK2/STAT4 pathway.
Keywords: interleukin-12, intracerebral hemorrhage, vascular regeneration, macrophages