Traumatic injury induced homer-1a gene expression in cultured cortical neurons of rat
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Updated: Aug 15, 2026
Controlled Cortical Impact Model for Traumatic Brain Injury
Published on: August 5, 2014
Wei-Dong Huang1, Zhou Fei, Xiang Zhang
1Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shannxi 710032, PR China.
Insights
Traumatic brain injury upregulates homer-1a gene expression in cultured rat neurons. Constitutively expressed homer-1b/c shows no change, suggesting homer-1a
Area of Science:
- Neuroscience
- Molecular Biology
- Cellular Biology
Background:
- Homer proteins are key postsynaptic density components.
- Homer-1a is an immediate early gene, dynamically expressed with neuronal activity.
- Homer-1b/c is constitutively expressed, unaffected by neuronal activity.
Purpose of the Study:
- To investigate the effect of traumatic brain injury on Homer-1a expression in cultured rat cortical neurons.
- To determine if Homer-1b/c expression is altered by traumatic injury.
Main Methods:
- Primary cortical neuron cultures from rat fetuses were established.
- Traumatic injury was induced using a standardized multi-blade punch device.
- Lactate dehydrogenase levels were measured to assess cell viability.
- Homer-1a and Homer-1b/c expression was analyzed via RT-PCR and Western blot at multiple time points post-injury.
Main Results:
- Homer-1a was not detected in control cultures but was significantly upregulated from 10 minutes to 72 hours after traumatic injury.
- Homer-1b/c was consistently detected in control cultures and showed no significant change in expression following traumatic stimulation.
- Cell viability was assessed via lactate dehydrogenase levels, indicating the impact of the injury model.
Conclusions:
- Traumatic stimulation induces homer-1a gene expression in cortical neurons.
- Dynamically expressed Homer-1a and constitutively expressed Homer-1b/c may modulate group I metabotropic glutamate receptor function after injury.
Abstract:
The Homer proteins belong to one of the newly found postsynaptic density protein families. As an immediately early gene, the homer-1a is dynamically expressed and is upregulated by synaptic activity. The homer-1b/c is constitutively expressed and there is no change of gene expression with neuronal activity. In this study, we investigated whether a traumatic injury might regulate the homer-1a expression in cultured cortical neurons of rat. After 7 days in vitro cultivation, the rat fetus cortical neurons were divided into control and injured groups. Then, a traumatic injury was performed on a cortical neuronal culture using a punch device that consisted of 28 stainless steel blades joined together, these produced parallel cuts of 1.2 mm that were uniformly distributed through the cell layer. The lactate dehydrogenase level of the neuronal cultures medium was evaluated and the expression patterns of homer-1a, homer-1b/c were analyzed with the method of RT-PCR and Western blot at different times after the injury (10, 30 min, 1, 3, 6, 12, 24, 72 h). It was shown that there was no expression of homer-1a in the control group, but homer-1a was upregulated in the period of 10 min to 72 h after the traumatic injury. The homer-1b/c was clearly observed in the control group, but there was no change in its expression after traumatic stimulation. It was concluded that traumatic stimulation could induce the homer-1a gene expression, dynamically expressed homer-1a and constitutively expressed homer-1b/c might modulate the distribution and function of group I metabotropic glutamate receptors.
