ABSTRACT
Objective To explore the dynamic changes and mechanisms of neurological and cognitive functions in mice with traumatic brain injury (TBI). Methods Totally 60 12⁃month⁃old Balb/ c mice were divided into control group (10 in group) and TBI group (50 in group). TBT model mice were divided into 5 subgroups according to the time of model construction, including model 1 day, model 1 day, model 3 day, model 7 day, model 14 days and model 28 days group with 10 in each group. At the 29th day of the experiment, neurological scores and step down tests were carried out. After the test, the mice were sacrificed for brains which were detected by immunohistochemistry staining, inflammatory cytokine tests and Western blotting. Results Compared with the control group, the neurological scores of mice in TBI group increased, and then decreased after the 7th day when the scores reached the peak. However, the latency of step down errors was lower than control group, and the number of step down errors was higher than control group which had no changes. Compared with the control group, the expression of lonized calcium⁃binding adapter molecule 1(IBA1), chemokine C⁃X3⁃C⁃motif ligand1 (CX3CL1), C⁃X3⁃C chemokine receptor 1(CX3CR1), NOD⁃like receptor thermal protein domain associated protein 3 (NLRP3), and phosphorylation nuclear factor(p⁃NF)⁃κB in TBI group increased and reached to the peak at the 7th day, and then started to decrease. At the same time, the levels of inflammatory cytokines interleukin⁃6(IL⁃6) and tumor necrosis factor⁃α(TNF⁃α) first increased to the peak, and then began to decrease. However, compared with the control group, the expression of amyloid β(Aβ) protein and p⁃Tau protein in the model group continued to increase at all time. Conclusion The TBI model caused continuous activation of microglia along with inflammatory response, which first increased and then decreased, resultsing in neurological scores changes. In addition, the inflammatory response may act as a promoter of Aβ protein deposition and Tau protein phosphorylation, leading to cognitive impairment in mice.
ABSTRACT
Dual-specificity phosphatase 8 (DUSP8) is a member of the dual-specificity phosphatase family, which has been reported to participate in the development of many diseases.However, it is unclear whether DUSP8 plays an important role in the inflammatory response of macrophages and related immune cells.This study aims to detect the expression of DUSP8 in lipopolysaccharide (LPS)-induced macrophage inflammatory responses and to observe the effect of DUSP8 overexpression on macrophage inflammatory responses.100 ng/ml LPS was used to treat bone marrow-derived macrophages (BMDMs) from wild-type C57BL/6 mice at different time points.Real-time PCR and Western blotting results showed that the expression of DUSP8 was significantly reduced in BMDMs (P<0.05) and reached the peak at 12 hours.Next, DUSP8 overexpression vectors (DUSP-EGFP) and control vectors (EGFP) were transfected into BMDM.Data showed that DUSP-EGFP transfection could significantly enhance the expression of DUSP8 in BMDMs (P<0.05).Moreover, FCM data showed that the expressions of CD80 and CD86 markedly decreased in BMDMs with DUSP8 overexpression (P< 0.05).Meanwhile, the neutral red uptake assay data showed that the uptake in DUSP8 overexpression group was lower than that in the control group.Furthermore, ELISA results showed DUSP8 overexpression could significantly reduce the production of IL-1(3 and IL-6 (P < 0.05).Besides, Western blotting results showed that the phosphorylation levels of p38 MAPK and JNK decreased in BMDMs after DUSP8 overexpression (P< 0.05).All together, DUSP8 overexpression could significantly ameliorate LPS-induced macrophage inflammation, which was mainly related to the reduced expression of phosphorylated p38 MAPK and JNK.