Effect of p38 mitogen-activated protein kinase pathway on hydrocephalus and aquaporin 4 expression in rats
10.3760/cma.j.cn115354-20211114-00738
- VernacularTitle:p38 MAPK通路对大鼠脑积水及水通道蛋白4表达的影响
- Author:
Zhangyu LI
1
;
Xin GAO
;
Jianyao MAO
;
Sifang CHEN
;
Guowei TAN
;
Zhanxiang WANG
Author Information
1. 厦门大学附属第一医院神经外科，厦门 361003
- Keywords:
Hydrocephalus;
p38 mitogen-activated protein kinase;
Aquaporin 4
- From:
Chinese Journal of Neuromedicine
2022;21(4):333-340
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To observe the regulatory effect of p38 mitogen-activated protein kinase (p38 MAPK) on aquaporin 4 (AQP4) in rats after hydrocephalus, and to explore its significance in hydrocephalus prevention.Methods:Fifty SD rats were randomly divided into sham-operated group ( n=10), hydrocephalus group ( n=20), and hydrocephalus+inhibitor (SB203580) group (SB group, n=20). The rat models of hydrocephalus in the latter two groups were prepared by intracerebroventricular injection of kaolin suspension; rats in the sham-operated group were injected with same amount of normal saline into the lateral ventricle. The p38 MAPK specific inhibitor SB203580 (10 mg/kg) was intraperitoneally injected into the rats of SB group on the 8 th d of modeling for 7 consecutive d; same volume of dimethylsulfoxide was given to the rats of hydrocephalus group on the 8 th d of modeling for 7 consecutive d; rats in the sham-operated group did not give any treatment. The severity of hydrocephalus in these rats was observed by MRI. The inflammatory factor tumor necrosis factor (TNF)-α level in the cerebrospinal fluid was detected by enzyme-linked immunosorbent assay (ELISA). The AQP4 and TNF-α mRNA expressions were detected by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). The phosphorylated p38 MAPK and AQP4 expressions in the periventricular brain tissues were detected by Western blotting and immunohistochemistry. Results:No hydrocephalus developed in sham-operated group and hydrocephalus developed in the latter two groups. As compared with sham-operated group, hydrocephalus group and SB group had significantly increased lateral ventricle volume, significantly aggravated periventricular edema, significantly higher EVAN's index, and statistically increased brain water content ( P<0.05). Two weeks after modeling, the TNF-α expression levels in cerebrospinal fluid of sham-operated group, hydrocephalus group and SB group were (20.49±0.96), (42.04±3.17), and (28.00±3.71) pg/mL, respectively, with significant differences ( F=186.000, P<0.001); the TNF-α expression level in SB group was significantly higher than that in sham-operated group and significantly lower than that in hydrocephalus group ( P<0.05). Two weeks after modeling, the TNF-α and AQP4 mRNA expression levels in brain tissues of the three groups were significantly different ( P<0.05); the TNF-α and AQP4 mRNA expression levels in hydrocephalus group were significantly higher than those in sham-operated group and SB group ( P<0.05). Correlation analysis showed that there was a positive linear correlation between AQP4 mRNA expression and TNF-α mRNA expression in hydrocephalus group ( r=0.511, P=0.026), and there was a positive linear correlation between AQP4 protein expression and phosphorylated p38 MAPK protein expression in hydrocephalus group and SB group ( r=0.560, P=0.013; r=0.463, P=0.030). Immunohistochemical staining results showed that AQP4 expression was abundant in glial cells of the three groups; the p38 MAPK distribution was uniform and non-polar; the phosphorylated p38 MAPK protein expression in the hydrocephalus group was significantly higher than that in the sham-operated group, and that in the SB group returned to the level of the sham-operated group. Conclusion:The p38 MAPK pathway is involved in the positive regulation of AQP4 expression, which could be inhibited by SB203580.
