Preexisting Interleukin-10 In Susceptible Cerebral Arteries May Decrease Subsequent Brain Injury Caused By Ischemic/Reperfusion

Objective: Recurrent stroke is common with no cure. Systemic interleukin-10 (IL-10) has cytoprotective effects for stroke but with significant side effect. Forced transduction of IL-10 gene in susceptible arteries achieved during interventional treatment management of the first stroke may increase local instead of systemic IL-10 in front and decrease brain damage of recurrent stroke. Methods: Recombinant adeno-associated viral vector 1 encoding rat IL-10 (rAAV1-IL-10), rAAV1-YFP, or saline were infused into left cerebral artery, respectively. Three weeks after, all animals were subjected to MCAO for 45min followed by reperfusion for 24h. ELISA and in situ hybridization using three DIG-labeled probes specific for rAAV1 backbone were performed to confirm the expression of IL-10. Neurologic dysfunction and infarct area were evaluated by neurological impaired use scores and TTC staining. Expressions of inflammatory mediators and endoplasmic reticulum stress proteins (ERP), including IL-1β, IL-10, TNF-α, MCP-1, MIP-1α, ICAM-1, TGF-β, VEGF, HO-1, ATF6 and CHOP, infarct boundary zone were measured by reverse transcription real time PCR. Results: Left cerebral artery of animals receiving rAAV1-IL-10 or rAAV1-YFP was stained positive for rAAV1 backbone. No positive staining was observed in animals perfused with PBS. The preexisting local IL-10 but not YFP decreased the neurological impaired use scores, infarct area and the number of injured neuronal cells. AAV1-IL-10 transduction decreased pro-inflammatory mediator TNF-α and increased intracellular protective protein HO-1. The increased expression of HO-1 was confirmed by Western blotting and immunohistochemical analysis. Other cytokines and ERP did not changed significantly. Conclusion: Preexisting IL-10 in susceptible cerebral arteries may decrease subsequent brain injury caused by ischemic/reperfusion through correcting pro-/anti-inflammatory balance and increasing intracellular protective proteins. Selective transduction of therapeutic gene in susceptible arteries during interventional stroke managements, such as thrombolysis and placing cerebrovascular stent, of the initial stroke is beneficial for recurrent stroke.