Carbenoxolone Modulates Dopamine D2 Receptor-Associated Inflammatory Responses After Ischemic Stress

Despite advances in reperfusion therapy, ischemic brain injury remains a major cause of disability. Astrocytes play a central role in postischemic inflammation and tissue remodeling, but the molecular drivers of their reactive state transitions remain unclear. Here, we investigated whether carbenoxolone modulates reactive astrocyte phenotypes through astrocytic Drd2 signaling after cerebral ischemia.

In vivo rat cerebral ischemia-reperfusion model and in vitro oxygen-glucose deprivation/reperfusion paradigms were used. Infarct volume and neurological outcomes were assessed in vivo. Transcriptomic profiling was performed by RNA sequencing, followed by validation of representative genes using quantitative real-time polymerase chain reaction. Functional effects were evaluated in astrocytes and neuron-astrocyte coculture systems, and the involvement of Drd2 was examined using genetic knockdown approaches.

Carbenoxolone reduced infarct volume and improved neurological outcomes both in the acute phase and 14 days after cerebral ischemia-reperfusion in rats. RNA sequencing revealed that carbenoxolone attenuated inflammatory signaling and reduced the expression of reactive astrocyte markers, including interleukin-1 beta and Cd44. RNA sequencing identified Drd2 as a prominently upregulated gene in carbenoxolone-treated rats compared with saline controls. These transcriptional changes were validated at both the mRNA level by quantitative real-time polymerase chain reaction and the protein level by Western blotting. Functionally, under oxygen-glucose deprivation/reperfusion conditions, carbenoxolone enhanced cell survival in astrocytes and neuron-astrocyte cocultures, but not in neurons alone, indicating an astrocyte-mediated protective effect. Genetic silencing of Drd2 increased the reactive astrocyte marker Cd44 (cluster of differentiation 44) under basal conditions and partially attenuated carbenoxolone-induced cytoprotection after oxygen-glucose deprivation/reperfusion.

Carbenoxolone modulates postischemic inflammatory responses and reactive astrocyte-associated programs, with evidence supporting a role for Drd2 signaling in these effects. These findings provide mechanistic insight into carbenoxolone-mediated neuroprotection and suggest Drd2 signaling as a potential therapeutic target in ischemic brain injury.