Improvement in mitochondrial function underlies the effects of ANNAO tablets on attenuating cerebral ischemia-reperfusion injuries

Ethnopharmacological relevance: ANNAO tablets derive from Chinese classical prescriptions of Angong Niuhuang Pills with modified compositions, which have been singly or combined used for stoke associated neurological disorders. However the underlying mechanism is not yet well-defined, the present study investigated its anti-ischemic effects in rat middle cerebral artery occlusion (MCAO) model and focused on mitochondrial quality control. Materials and methods: Rats were subjected to 2 h of brain ischemia followed by 1 day or up to 7 days of reperfusion. Vehicle, ANNAO tablets or Edaravone were given at 1h after the start of reperfusion for 1 day or successive 7 days in MCAO rats. For the behavior assessment, Longa test and modified Neurological Severity Scores (mNSS) test were performed. Following the behavioral assessment, we assessed the protein expressions related to mitochondrial function. Moreover, we also assessed the neuroprotective effects of ANNAO tablets by immunohistochemical analysis. Results: Compared with sham rats, ANNAO tablets improved the behavioral performance and decreased the infarction volume in the MCAO rats. Western blotting results showed that ANNAO tablets altered the expression level of multiple proteins related to mitochondrial function, elevated the ratio of Bcl-2/Bax and inhibited the apoptosis. Additionally, ANNAO tablets increased the number of NeuN positive neurons. Conclusions: The obtained data demonstrated that ANNAO tablets exhibited an obvious anti-cerebral ischemia-reperfusion effect, which could be attributed to the improvement of mitochondrial quality control.