Protective effects of andrographolide against cerebral ischemia-reperfusion injury in mice

Ischemic stroke is one of the most common causes of mortality worldwide and is a primary cause of disability and mortality in adults. There is an unmet need for drugs that can effectively treat ischemic stroke. Hence, the present study explored the neuroprotective effects of andrographolide (Andro) in a mouse model of bilateral common carotid artery occlusion, and systematically evaluated the potential mechanisms underlying its effects. The effects of Andro on mouse brain tissue following cerebral ischemia-reperfusion injury (CIRI) were evaluated by histopathological (H&E and Nissl) and immunofluorescence [glial fibrillary acidic protein (GFAP) and neuronal nuclei (NeuN)] staining. A traditional Chinese medicine-based network pharmacology method was performed to establish and analyze compound-target-disease and function-pathway networks in order to elucidate the possible mechanisms responsible for the protective role of Andrographis paniculata in CIRI. In addition, western blot analysis and RT-qPCR was performed to evaluate the expression and activation of signaling proteins predicted to be involved in this mechanism. The amelioration of histopathological alterations was observed in mice pre-treated with Andro. Immunofluorescence staining revealed that Andro decreased the expression of GFAP and increased the expression of NeuN, and significantly decreased the levels of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α). Network pharmacology analysis revealed that neuroinflammatory response and apoptosis were associated with the effects of Andrographis paniculata on CIRI. Western blot analysis revealed that the mice pre-treated with Andro exhibited an upregulated protein expression of tropomyosin receptor kinase B (TrkB), p-PI3K and p-Akt, as well as a decrease in the expression of GFAP and an increase in the expression of NeuN. In addition, the data of RT-qPCR indicated that the mice pre-treated with Andro exhibited a significantly decreased expression of encoding IL-1β mRNA, IL-6 mRNA and TNF-α mRNA in the brain compared to the untreated mice following CIRI. On the whole, the findings of the present study suggest that pre-treatment with Andro exerts a protective effect against CIRI, which may be partly related to its potential to reduce neuroinflammatory response and apoptosis in patients with stroke.