Reactivating effect of myo-inositol on ocular dominance plasticity in the visual cortex of adult mice and its mechanisms

Objective  To investigate the effect of myo-inositol on the reactivation of ocular dominance plasticity in the visual cortex of adult mice and its mechanisms.

Methods  Thirty-two male SPF-grade C57BL/6J mice at postnatal day 60 (P60) were randomly divided into four groups using a random number table: normal control group, monocular form deprivation (MD) group, myo-inositol group (myo-inositol administered to normal mice), and MD+ myo-inositol group (myo-inositol administered to MD mice), with 8 mice in each group.The right eyes of MD group and MD+ myo-inositol group received MD on P60.Mice in each group were housed until P64 when pattern visual evoked potential (P-VEP) recordings were performed in both eyes.The amplitude and peak time of P100 wave were measured, and the contralateral/ipsilateral ratio (C/I) was calculated to evaluate the shift of ocular dominance.Twenty-four mice were randomly divided into MD group and MD+ myo-inositol group using the random number table method, with 12 mice in each group.RNA was extracted from the visual cortex of the two groups of mice, and transcriptomic sequencing and bioinformatics analysis were performed to screen differentially expressed genes.Six mice were randomly divided into MD group and MD+ myo-inositol group using the random number table method, with 3 mice in each group, and the expression changes of differentially expressed genes cell communication network factor 1( CCN1), fatty acid binding protein 7( Fabp7) and galectin-3 binding protein ( Lgals3bp) were verified by real-time fluorescence quantitative PCR.This study adhered to the Regulations on the Administration of Laboratory Animals (2017 Edition), and the research protocol was approved by the Animal Ethics Committee of Tianjin Medical University (No.TMUaMEC2022004).

Results  The P-VEP results showed that the right eye P100 amplitudes in the normal control, MD, myo-inositol and MD+ myo-inositol groups were (89.04±19.87), (83.04±9.42), (88.14±21.75) and (61.75±15.42)μV, and the P100 wave peak time were (102.40±5.64), (101.50±8.26), (101.33±8.66) and (111.30±7.17)ms, and C/I were 2.38±0.17, 2.35±0.22, 2.41±0.31, and 1.65±0.24, respectively, with statistically significant overall differences ( F=5.844, 2.221, 16.634; all P<0.05).Compared with the normal control group, MD group and myo-inositol group, the MD+ myo-inositol group had a significant decrease in the P100 wave amplitude in the right eye, a significant prolongation of the P100 wave peak time, and a significant decrease in the C/I, with statistically significant differences (all P<0.05).There was no significant difference in P100 wave amplitude or peak time in the left eyes among the normal control, MD, myo-inositol and MD+ myo-inositol groups ( F=0.249, 1.356; both P>0.05).The transcriptome sequencing results showed that there were significant differences in the expression of 93 genes between the MD+ myo-inositol group and the MD group, among which the differential expression of CCN1, Fabp7 and Lgals3bp genes related to visual plasticity was particularly significant.The real-time fluorescence quantitative PCR results verified that the expression of CCN1 in the MD+ myo-inositol group was significantly decreased, and the expression of Fabp7 and Lgals3bp was significantly increased, with statistically significant differences ( t=17.561, 9.237, 12.710; all P<0.001).

Conclusions  Myo-inositol can effectively reactivate ocular dominance plasticity in the visual cortex in adult mice, and may mediate this process by regulating the expression of specific genes CCN1, Fabp7, and Lgals3bp.

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