Dual antiplatelet therapy improves functional recovery and inhibits inflammation after cerebral ischemia/reperfusion injury

Abstract

Background: Dual antiplatelet therapy with aspirin and clopidogrel (ASA + CPG) during the first 21 days has been shown to reduce the risk of major ischemic events in patients with transient ischemic attack (TIA) or minor stroke. However, the mechanisms underlying combination treatment with ASA + CPG in experimental ischemic stroke has not been fully elucidated. Methods: Minor cerebral ischemia was induced in mice by transient distal middle cerebral artery occlusion (tdMCAO). Two doses of ASA + CPG (12 and 24 mg/kg/day) or vehicle were administered by gavage daily. Neurological behaviors were assessed using the modified Garcia scores, Rotarod test, Y maze, and open field test. Platelet function was assessed in vitro by flow cytometry and in vivo by bleeding and clotting time. The neutrophil ratio and the levels of inflammatory cytokines were measured by flow cytometry and the Meso Scale Discovery (MSD) electrochemilunimescence, respectively.Results: Sensorimotor function was partially recovered with ASA + CPG treatment after ischemia. Anxiety levels and cognitive functions showed improvement in the ASA + CPG group at 12 mg/kg/day after 21 days.Both tail bleeding time and flow cytometry showed significantly decreased platelet function after ASA + CPG treatment. Notably, ASA + CPG at 12 mg/kg/day prolonged clotting time at 28 days after injury. Furthermore, the ratio of neutrophils, an indicator of inflammation, was reduced with 12 mg/kg/day ASA + CPG treatment in the bone marrow (BM) at 21 days and in the peripheral blood (PB) at 21 and 28 days after tdMCAO. Both doses of ASA + CPG decreased pro-inflammatory cytokine interleukin (IL)-6 expression 21 days after stroke.Taken together, these results demonstrated that combination treatment with ASA + CPG improved longterm neurological function after stroke and may inhibit platelet-neutrophil interaction by decreasing the concentration of pro-inflammatory cytokine, IL-6.Conclusions: These findings indicate a neuroprotective effect of combination treatment with ASA + CPG for a duration of 21 days in an experimental acute minor stroke model. These findings provide further evidence that dual antiplatelet therapy may be a viable neuroprotective treatment to decrease the recurrence of stroke.

Neutrophil modulation of behavior and cognition in health and disease: The unexplored role of an innate immune cell

“…Inhibition of platelet activation led to a decrease in interleukin‐6 levels, which are normally elevated in this model. Furthermore, these decreases correlated to better motor and Y‐maze performance and a decreased risk of further stroke in mice 41 . This correlation would suggest that neutrophil activation after this mild injury can lead to changes in brain function.…”

“…Furthermore, these decreases correlated to better motor and Y‐maze performance and a decreased risk of further stroke in mice. 41 This correlation would suggest that neutrophil activation after this mild injury can lead to changes in brain function. Unfortunately, the authors did not characterize the damage to the brain following this injury.…”

Clopidogrel Administration Impairs Post-Stroke Learning and Memory Recovery in Mice

“…It would be interesting to see whether these studies would report similar results if the duration of their experiments was longer. More recently, Dong et al [53] assessed the effect of dual antiplatelet therapy with aspirin and clopidogrel on cognition in mice with transient distal middle cerebral artery occlusion. They used the Y-maze and novel object recognition tests for the assessment of cognitive function [53].…”

“…More recently, Dong et al [53] assessed the effect of dual antiplatelet therapy with aspirin and clopidogrel on cognition in mice with transient distal middle cerebral artery occlusion. They used the Y-maze and novel object recognition tests for the assessment of cognitive function [53]. The results of the Y-maze test showed that short-term memory was restored only in the 12 mg/kg aspirin + clopidogrel group on day 21, but not on days 14 or 28 after ischemia [53].…”

“…They used the Y-maze and novel object recognition tests for the assessment of cognitive function [53]. The results of the Y-maze test showed that short-term memory was restored only in the 12 mg/kg aspirin + clopidogrel group on day 21, but not on days 14 or 28 after ischemia [53]. The results of the novel object recognition test showed no significant difference in recognition memory at any of the time points for both doses of the aspirin + clopidogrel groups when compared with the control group [53].…”