Effect of visual stimulation on epilepsy susceptibility in neonatal hypoglycemic brain injury rats during development

TL;DR

This study shows that visual stimulation can reduce epilepsy risk in rats with neonatal brain injury caused by low blood sugar, possibly by boosting brain growth factors.

Contribution

The study introduces visual stimulation as a novel intervention to reduce epilepsy susceptibility in neonatal hypoglycemic brain injury.

Findings

Visual stimulation reduced seizure scores in hypoglycemic brain injury rats compared to non-stimulated rats.

MRI showed occipital lobe abnormalities in 50% of hypoglycemic rats but not in controls.

BDNF and SYN expression increased in the visual stimulation group compared to the non-stimulated hypoglycemic group.

Abstract

To investigate the effect of visual stimulation on epilepsy susceptibility in neonatal hypoglycemic brain injury (HBIN) rats and its underlying mechanisms.

Seventy-five 2-day-old Sprague–Dawley rats were divided into three groups: control (N, N = 25), model (NH, N = 25), and visual stimulation (NH-V, N = 25). The NH and NH-V groups were injected with insulin (40 U/kg) on postnatal days 2, 4, and 6, and blood glucose was monitored. The NH-V group received daily 2-h visual stimulation from P14 to P28. At P21, brain Magnetic Resonance Imaging (MRI) was performed. Pentylenetetrazol (PTZ) was injected to induce seizures and recorded at P28. Brain tissue was analyzed for Brain-Derived Neurotrophic Factor (BDNF) and Synaptophysin (SYN) expression.

(i) In the NH and NH-V groups, blood glucose decreased after insulin injection, with behavioral changes observed at 1–4 h. One rat in the NH group had spontaneous seizures. (ii) MRI at 15 days showed occipital lobe abnormalities in 50% of NH rats, with no changes in controls. (iii) In PTZ-induced seizures, the N group had significantly lower seizure scores than the NH group, with the NH-V group showing further reduction. (iv) BDNF and SYN expression were higher in the NH-V group compared to the NH group.

Visual stimulation reduces epilepsy susceptibility in neonatal HBIN rats, likely through upregulation of BDNF and SYN expression in the occipital cortex.

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