Activation of p38 MAPK hinders the reactivation of visual cortical plasticity in adult amblyopic mice

Guiqu Wang; Peixian Hou; Yanqiong Tu; Jing Zheng; Pinxiong Li; Longqian Liu

doi:10.1016/j.exer.2023.109651

Activation of p38 MAPK hinders the reactivation of visual cortical plasticity in adult amblyopic mice

Exp Eye Res. 2023 Nov:236:109651. doi: 10.1016/j.exer.2023.109651. Epub 2023 Sep 23.

Authors

Guiqu Wang¹, Peixian Hou², Yanqiong Tu², Jing Zheng², Pinxiong Li³, Longqian Liu⁴

Affiliations

¹ Department of Ophthalmology, West China Hospital, Sichuan University, 37 Guoxue Xiang, Chengdu, 610041, China; Department of Ophthalmology, The Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Luzhou, 646000, China.
² Department of Ophthalmology, West China Hospital, Sichuan University, 37 Guoxue Xiang, Chengdu, 610041, China.
³ Department of Radiology, The Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Luzhou, 646000, China.
⁴ Department of Ophthalmology, West China Hospital, Sichuan University, 37 Guoxue Xiang, Chengdu, 610041, China; Department of Optometry and Visual Science, West China Hospital, Sichuan University, Chengdu, 610041, China. Electronic address: b.q15651@hotmail.com.

PMID: 37748716
DOI: 10.1016/j.exer.2023.109651

Abstract

Objective: To investigate the impact of p38 mitogen-activated protein kinase (MAPK) signaling on reactivating visual cortical plasticity in adult amblyopic mice.

Materials and methods: Reverse suture (RS), environment enrichment (EE), and combined with left intracerebroventricular injection of p38 MAPK inhibitor (SB203580, SB) or p38 MAPK agonist (dehydrocorydaline hydrochloride, DHC) were utilized to treat adult amblyopic mice with monocular deprivation (MD). The visual water task, visual cliff test, and Flash visual-evoked potential were used to measure the visual function. Then, Golgi staining and transmission electron microscopy were used to assess the reactivation of structural plasticity in adult amblyopic mice. Western blot and immunohistochemistry detected the expression of ATF2, PSD-95, p38 MAPK, and phospho-p38 MAPK in the left visual cortex.

Results: No statistically significant difference was observed in the visual function in each pre-intervention group. Compared to pre-intervention, the visual acuity of deprived eyes was improved significantly, the impairment of visual depth perception was alleviated, and the P wave amplitude and C/I ratio were increased in the EE + RS, the EE + RS + SB, and the EE + RS + DMSO groups, but no significant difference was detected in the EE + RS + DHC group. Compared to EE + RS + DHC group, the density of dendritic spines was significantly higher, the synaptic density of the left visual cortex increased significantly, the length of the active synaptic zone increased, and the thickness of post-synaptic density (PSD) thickened in the left visual cortex of EE + RS, EE + RS + SB, and EE + RS + DMSO groups. And that, the protein expression of p-p38 MAPK increased while that of PSD-95 and ATF2 decreased significantly in the left visual cortex of the EE + RS + DHC group mice.

Conclusion: RS and EE intervention improved the visual function and synaptic plasticity of the visual cortex in adult amblyopic mice. However, activating p38 MAPK hinders the recovery of visual function by upregulating the phosphorylation of p38 MAPK and decreasing the ATF2 protein expression.

Keywords: Environment enrichment; Monocular deprivation; Reversed suture; Visual cortical plasticity; p38 MAPK signaling.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amblyopia*
Animals
Dimethyl Sulfoxide
Mice
Vision, Ocular
Visual Cortex*
p38 Mitogen-Activated Protein Kinases / metabolism

Substances

p38 Mitogen-Activated Protein Kinases
Dimethyl Sulfoxide