Immunoproteasome inhibitors regulate the balance of T helper cells 17/regulatory T cells on hypoxic-ischemic brain injury of neonatal rats / 中华实用儿科临床杂志

ABSTRACT

Objective:To explore the effects and mechanism of PR-957 on hypoxic-ischemic brain damage(HIBD) of newborn rats.Methods:A total of 54 rats aged seven days were recruited and randomly divided into sham operation group, HIBD group and PR-957 intraperitoneal group.HIBD model was established according to modified Rice method.PR-957 group was given intraperitoneal injection PR-957(20 mg/kg) after hypoxic-ischemic.Model group was intraperitoneally injected with equal volume of DMSO.Ligation or hypoxic treatment were not given in sham operation group.HE staining was applied to observe inflammation in cortex.Immunohistochemical analysis was adopted to observe the expression of interleukin(IL)-17 and IL-10 in brain tissue.Western blot was carried out to test the protein level of low molecular poly peptide 7 (LMP7), forkhead box P3(FOXP3), and retinoic acid-recepter-related orphan receptor gamma t(RORγt). The proportion of T helper cells 17(Th17)/Treg was detected by flow cytometry.Results:HE staining displayed that sham operation group brain structure was basically normal, HIBD group revealed significant inflammation in the left cerebral cortex, while some pathological improvement was observed in PR-957 group.Immunohistochemistry IL-10 positive cells in left cortex of HIBD group [(12.11±3.73)%] were lower than sham operation group[(29.12±3.95)%] and PR-957 group[(22.61±6.59)%], and the differences were statistically significant (all P<0.05). IL-17 positive cells in the left cortex of HIBD group [(35.55±4.85)%] were higher than sham operation group [(8.48±2.58)%] and PR-957 group [(19.16±4.31)%], and the differences were statistically significant (all P<0.05). Western blot the expression of LMP7 and RORγt in HIBD group (1.01±0.12, 0.71±0.10) were higher than those in sham operation group (0.50±0.10, 0.34±0.07) and PR-957 group (0.65±0.13, 0.54±0.07), and the differences were statistically significant ( P<0.05). The expression of FOXP3 in HIBD group (0.44±0.10) was lower than sham operation group (0.93±0.07) and PR-957 group (0.68±0.09), and the differences were statistically significant (all P<0.05). The flow cytometry of peripheral blood the Th17/Treg ratio of HIBD group (0.66±0.24) was higher than sham operation group (0.20±0.09) and PR-957 group (0.45±0.18), and the differences were statistically significant (all P<0.05). Conclusion:PR-957 can regulate the immune balance of Th17/Treg cells and reduce the inflammatory in the brain tissues of HIBD newborn rats.