Propofol Ameliorates Ischemic Brain Injury by Blocking Toll-like Receptor 4-dependent Pathway and Suppressing Consequent Inflammatory Cytokine Production

Abstract

BackgroundIschemic stroke is one of the leading causes of mortality and morbidity worldwide. Accumulated evidence suggests that the consequent excessive inflammation plays detrimental roles in the pathogenesis of secondary injury after cerebral infarction and exacerbates the brain tissue damage. Although regulation of the inflammation would be the potential strategy for the novel treatment option, effective methods that control the cerebral inflammation have not yet been established. Recent studies have suggested that propofol, a sedative agent widely used for management of patients with acute stroke, suppresses excessive inflammation and may have neuroprotective effects against ischemic brain injury. However, the available evidence is still limited and controversial, and the underlying mechanism remains unclear. This study aimed to investigate the neuroprotective effects of propofol against ischemic brain injury, with a specific focus on Toll-like receptor 4 (TLR4), the critical mediator of inflammation in the ischemic brain.ResultsTreatment with propofol significantly reduced infarct volume in wild-type mice (7.9 ± 1.4 vs. 12.6 ± 1.1 mm3, n = 10 each, p < 0.05). The propofol-treated mice exhibited lower levels of pro-inflammatory cytokine expressions compared with the control mice (IL-6: 0.57 ± 0.23 vs. 1.00 ± 0.39, p < 0.05, IL-1β: 0.53 ± 0.24 vs. 1.00 ± 0.36, p = 0.087, n = 15 each). The neuroprotective effect of propofol was abrogated by TLR4 gene knockout. Propofol treatment had no significant effects on hemodynamic parameters.ConclusionsPropofol attenuates brain injury by blocking the TLR4-dependent pathway and suppressing pro-inflammatory cytokine production. This insight into the mechanism underlying the neuroprotective effect of propofol against ischemic brain injury may lead to a new strategy for preventing exacerbation of cerebral infarction.

Toll-Like Receptor Signaling Pathways: Novel Therapeutic Targets for Cerebrovascular Disorders

“…In one study, Propofol, a sedative drug, could exert anti-inflammatory properties via the downregulation of TLRs and reduction of pro-inflammatory cytokines [ 178 , 179 ]. The application of propofol significantly reduced infarct volume and pro-inflammatory cytokines in a mouse model of AIS [ 180 ]. As a result, the prophylactic application of TLR4 modulators has been suggested as a novel approach for the prevention of neuroinflammation and AIS tissue injury [ 131 , 181 ].…”