This study investigates the effects of focal ischemia and subsequent reperfusion on neuronal injury in a mouse model. It highlights the role of acidosis postconditioning in mitigating oxidative stress and promoting neuroprotection.
Take an anesthetized mouse with a monofilament inserted into its middle cerebral artery to induce occlusion.
This blocks blood flow to the brain, triggering focal ischemia.
The occlusion restricts oxygen and glucose supply, causing ATP depletion and neuronal depolarization.
Depolarized neurons release excess glutamate, which binds to postsynaptic receptors, causing a massive calcium influx.
Elevated intracellular calcium disrupts mitochondrial function and promotes ROS production, initiating neuronal damage.
Re-anesthetize the mouse.
Reopen the incision and remove the monofilament to achieve reperfusion.
Sudden oxygen reintroduction generates excess ROS from dysfunctional mitochondria, worsening neuronal injury.
To mitigate this, expose the mouse to a high-carbon dioxide gas mixture for acidic postconditioning or APC after reperfusion begins.
This increases proton concentration in the brain, inhibiting receptors, reducing calcium influx and preventing calcium-mediated excitotoxicity.
Additionally, APC stabilizes mitochondria and inhibits ROS production, thereby providing neuroprotection.
55 minutes after the start of occlusion, re-anesthetize the animal with isoflurane and position the animal as before. Then open the neck incision and re-expose the common carotid artery. After the occlusion period, use ophthalmic forceps to gently pull out the filament to achieve reperfusion. Then turn the temporary suture into a permanent one by tightening the knot. For acidosis treatment, change the gas inhaled by the nose cone to 20% carbon dioxide, 20% oxygen, and 60% nitrogen for five minutes. After closing the incision with an interrupted surgical suture, place the mouse in a 30 degree Celsius heated cage until the mouse regains consciousness.
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