Paeonol alleviates brain glucose hypometabolism in streptozotocin murine model of sporadic Alzheimer’s disease using microPET imaging

Intracerebroventricular (ICV) injection of streptozotocin (STZ) in rodents causes a model of sporadic Alzheimer's disease (sAD) with development of insulin resistance and neuronal dysfunction. Paeonol is a phenolic agent with neuroprotective effect due to its anti-inflammatory and anti-oxidant effects. This study was conducted to assess its beneficial effect in prevention of brain glucose hypometabolism in ICV STZ rat model of sAD.
STZ (3 mg/kg) was bilaterally injected ICV on days 0 and 2 using stereotaxic surgery and paeonol was orally given at two doses of 25 (low) or 100 (high) mg/kg from day 0 (post-surgery) till day 24 post-STZ. At the end of study, positron emission tomography (PET) imaging was employed with a micro-PET scanner through tail vein injection of 18FDG and brain to background ratio (BBR) was calculated.
ICV-STZ group had a significantly low BBR compared to sham group. In contrast, ICV-STZ group treated with paeonol at a dose of 100 mg/kg had a significantly higher BBR as compared to ICV-STZ group, clearly indicating attenuation of brain glucose hypometabolism. In addition, paeonol at a dose of 25 mg/kg did not significantly improve BBR in ICV-STZ group.
In summary, these results revealed the beneficial dose-dependent effect of paeonol in amelioration of brain glucose hypometabolism in STZ-induced model of sAD.