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Published on: January 3, 2025
Therapeutic targets and limits of minocycline neuroprotection in experimental ischemic stroke
Noriyuki Matsukawa1, Takao Yasuhara, Koichi Hara
1Department of Neurology, Medical College of Georgia, Augusta, GA 30912, USA. norim@med.nagoya-cu.ac.jp
Background:
Minocycline, a second-generation tetracycline with anti-inflammatory and anti-apoptotic properties, has been shown to promote therapeutic benefits in experimental stroke. However, equally compelling evidence demonstrates that the drug exerts variable and even detrimental effects in many neurological disease models. Assessment of the mechanism underlying minocycline neuroprotection should clarify the drug's clinical value in acute stroke setting.
Results:
Here, we demonstrate that minocycline attenuates both in vitro (oxygen glucose deprivation) and in vivo (middle cerebral artery occlusion) experimentally induced ischemic deficits by direct inhibition of apoptotic-like neuronal cell death involving the anti-apoptotic Bcl-2/cytochrome c pathway. Such anti-apoptotic effect of minocycline is seen in neurons, but not apparent in astrocytes. Our data further indicate that the neuroprotection is dose-dependent, in that only low dose minocycline inhibits neuronal cell death cascades at the acute stroke phase, whereas the high dose exacerbates the ischemic injury.
Conclusion:
The present study advises our community to proceed with caution to use the minimally invasive intravenous delivery of low dose minocycline in order to afford neuroprotection that is safe for stroke.
Insights
Low-dose minocycline protects neurons from stroke-induced cell death by inhibiting apoptosis. High doses may worsen injury, so cautious, low-dose intravenous use is recommended for stroke neuroprotection.
Area of Science:
- Neuroscience
- Pharmacology
- Cell Biology
Background:
- Minocycline, a tetracycline antibiotic, exhibits anti-inflammatory and anti-apoptotic properties.
- Previous studies show mixed results regarding minocycline's efficacy in neurological disease models.
- Understanding minocycline's neuroprotective mechanisms is crucial for its clinical application in stroke.
Purpose of the Study:
- To investigate the mechanism of minocycline-induced neuroprotection in experimental stroke.
- To determine the dose-dependent effects of minocycline on neuronal survival after ischemic injury.
Main Methods:
- In vitro studies using oxygen-glucose deprivation (OGD) to mimic ischemic conditions.
- In vivo studies utilizing middle cerebral artery occlusion (MCAO) models in rodents.
- Analysis of the Bcl-2/cytochrome c apoptotic pathway in neurons and astrocytes.
Main Results:
- Minocycline attenuated ischemic deficits in both in vitro and in vivo models.
- Neuroprotection was attributed to direct inhibition of neuronal apoptosis via the Bcl-2/cytochrome c pathway.
- The anti-apoptotic effect was specific to neurons, not astrocytes.
- Low-dose minocycline inhibited cell death, while high-dose minocycline exacerbated ischemic injury.
Conclusions:
- Minocycline demonstrates neuroprotective effects in experimental stroke by inhibiting neuronal apoptosis.
- The neuroprotective mechanism is dose-dependent, with low doses being beneficial and high doses detrimental.
- Cautious use of low-dose, intravenously administered minocycline is advised for safe neuroprotection in stroke patients.
