Granulocyte-colony stimulating factor exerts its neuroprotective effects by regulating inflammatory cascades via mTOR/p70SK6 signaling pathway when hypoxia-ischemia occurs in neonatal rats
10.3760/cma.j.issn.2095-428X.2018.14.015
- VernacularTitle: 粒细胞集落刺激因子通过mTOR/p70S6K途径调节新生大鼠缺氧缺血性脑损伤后炎症反应
- Author:
John Sieh DUMBUYA
1
;
Siyun SHU
1
;
Zhengyan WU
2
;
Lin MA
3
;
Jiang DU
1
;
Lu CHEN
1
;
Wei LUO
1
;
Fei LI
1
;
Bin WANG
1
Author Information
1. Department of Pediatrics, Zhujiang Hospital, Southern Medical University, Guangzhou Key Laboratory of Inflammation and Immune Diseases, Guangzhou 510282, China
2. Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton 33431, Florida, USA
3. Department of Radiotherapy, Chinese People′s Liberation Army General Hospital, Beijing 100853, China
- Publication Type:Journal Article
- Keywords:
Hypoxic-ischemic brain damage;
Granulocyte-colony stimulating factor;
Mammalian target of Rapamycin/p70 ribosomal S6 protein kinase;
Inflammatory cytokine;
Rat, newborn
- From:
Chinese Journal of Applied Clinical Pediatrics
2018;33(14):1107-1111
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the role of granulocyte-colony stimulating factor (G-CSF) on the regulation of inflammatory cytokines in neonatal hypoxic-ischemic brain damage(HIBD) rat model, and to explore the possible mechanism involved in G-CSF neuroprotective effect via the mammalian target of Rapamycin/p70 ribosomal S6 protein kinase (mTOR/p70S6K) signaling pathway.
Methods:A group of postnatal day 7 (P7) Sprague-Dawley rat pups (90 cases) were randomly divided into sham-operated group, hypoxia-ischemia(HI) group, G-CSF group, Rapamycin (RAP) group and control group, and the improved Rice method was used to establish a neonatal rat model of HIBD.One hour before HI induction, Rapamycin was administered intraperitoneally with a dose of 250 μg/kg, and the control group was given equal volume of ethanol injected intraperitoneally.One hour after HI, a dose of 50 μg/kg of G-CSF was injected intraperitoneally into the G-CSF group, Rapamycin group and control group.The same volume of normal saline was injected intraperitoneally into HI group and sham-operated group.Forty-eight hours after HI, Western blot was used to detect the protein levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-10, and the mTOR/p70S6K signaling pathway in brain tissue.Neuron injury of the hippocampal CA1 region and the cortex was assessed by Nissl staining, and infarct volume detected by 2, 3, 5-triphenyltetrazolium chloride staining.
Results:The G-CSF group and control group were associated with significantly reduced infarction volume compared to the HI group [(12.87±1.54)%, (11.90±1.31)% vs.(24.21±3.28)%], and the differences were statistically significant(P<0.05). There was an increased positive neuron cell number in the ipsilateral hemispheres of the hippocampal CA1 region in the G-CSF group and the control group [(61.00±4.90) cell/field and (61.67±6.40) cell/field] and cortex [(92.67±6.68) cell/field and (90.17±4.45) cell/field] compared with those in HI group [(42.62±4.46) cell/field and (70.83±6.97) cell/field], and the differences were all statistically significant (all P<0.05). The expression levels of TNF-α and IL-1β were significantly decreased in the G-CSF group and the control group, compared with those in HI group(TNF-α: 0.67±0.07, 0.55±0.05 vs.0.86±0.05; IL-1β: 0.65±0.06, 0.52±0.10 vs.0.86±0.06), and the differences were all statistically significant (all P<0.05). There was increased expression levels of IL-10, p-mTOR/mTOR and p-p70S6K/p70S6K in the G-CSF group and the control group, compared with those in HI group (IL-10: 0.68±0.04, 0.62±0.05 vs.0.34±0.02; p-mTOR/mTOR: 0.53±0.02, 0.51±0.01 vs.0.26±0.01; p-p70S6K/p70S6K: 0.89±0.03, 0.90±0.03 vs.0.55±0.02), and the differences were all statistically significant(all P<0.05). There was an increased infarct volume in Rapamycin group [(25.70±1.50)%], compared with the G-CSF group and the control group, and there were decreased number of positive neuron cell count in the hippocampal CA1 region [(40.67±3.50) cell/field] and cortex [(68.33±8.17) cell/field], increased expression levels of TNF-α and IL-1β (0.97±0.06 and 0.98±0.10, respectively), decreased expression levels of IL-10, p-mTOR/mTOR and p-p70S6K/p70S6K (0.21±0.02, 0.30±0.01 and 0.55±0.01, respectively) in the Rapamycin group, and the differences were all statistically significant (all P<0.05).
Conclusions:G-CSF may inhibit inflammatory responses after HIBD by up-regulating the mTOR/p70S6K signaling pathway in neonatal HI encephalopathy.
