Related Experiment Video
Updated: May 2, 2026
Isolation and Flow Cytometric Assessment of Neuroimmune Interactions in a Mini-Stroke Murine Model
Published on: June 20, 2025
Microglia is a key player in the reduction of stroke damage promoted by the new antithrombotic agent ticagrelor
Paolo Gelosa1, Davide Lecca1, Marta Fumagalli1
1Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy.
Abstract:
The ADP-responsive P2Y12 receptor is expressed on both platelets and microglia. Clinical data show that ticagrelor, a direct-acting, reversibly binding P2Y12-receptor antagonist, reduces total cardiovascular events, including stroke. In our present study, we investigated the expression of P2Y12 receptors and the effects of ticagrelor on brain injury in Sprague-Dawley rats subjected to a permanent middle cerebral artery occlusion (MCAo). Rats were treated per os with ticagrelor 3 mg/kg or vehicle at 10 minutes, 22, and 36 hours after MCAo and killed after 48 hours. Immunofluorescence analysis showed an ischemia-related modulation of the P2Y12 receptor, which is constitutively expressed in Iba1(+) resting microglia. After MCAo, activated microglia was mainly concentrated around the lesion, with fewer cells present inside the ischemic core. Ticagrelor significantly attenuated the evolution of ischemic damage-evaluated by magnetic resonance imaging (MRI) at 2, 24, and 48 hours after MCAo-, the number of infiltrating cells expressing the microglia/monocyte marker ED-1, the cerebral expression of proinflammatory mediators (interleukin 1 (IL-1), monocyte chemoattractant protein 1 (MCP-1), nitric oxide synthase (iNOS)) and the associated neurologic impairment. In transgenic fluorescent reporter CX3CR1-green fluorescent protein (GFP) mice, 72 hours after MCAo, ticagrelor markedly reduced GFP(+) microglia and both early and late infiltrating blood-borne cells. Finally, in primary cultured microglia, ticagrelor fully inhibited ADP-induced chemotaxis (P<0.01). Our results show that ticagrelor is protective against ischemia-induced cerebral injury and this effect is mediated, at least partly, by inhibition of P2Y12-mediated microglia activation and chemotaxis.
Insights
Ticagrelor, a P2Y12 receptor antagonist, protects against stroke-induced brain injury by reducing microglia activation and inflammation. This study shows ticagrelor
Area of Science:
- Neuroscience
- Pharmacology
- Cardiovascular Research
Background:
- The P2Y12 receptor is present on platelets and microglia, and its antagonist ticagrelor reduces cardiovascular events.
- Microglia play a role in brain injury following ischemic stroke.
Purpose of the Study:
- To investigate P2Y12 receptor expression and the effects of ticagrelor on cerebral injury in a rat stroke model.
- To determine if ticagrelor's neuroprotective effects are mediated by inhibiting microglia activation.
Main Methods:
- Permanent middle cerebral artery occlusion (MCAo) model in Sprague-Dawley rats and CX3CR1-GFP mice.
- Treatment with ticagrelor or vehicle, followed by MRI, immunofluorescence, and assessment of inflammatory mediators.
- In vitro studies on primary cultured microglia to assess ADP-induced chemotaxis.
Main Results:
- Ticagrelor significantly attenuated ischemic brain damage, reduced inflammatory cell infiltration, and decreased pro-inflammatory mediators.
- Ticagrelor reduced microglia activation and infiltration of blood-borne cells in the brain post-MCAo.
- Ticagrelor inhibited ADP-induced microglia chemotaxis in vitro.
Conclusions:
- Ticagrelor demonstrates neuroprotective effects against ischemia-induced cerebral injury.
- These protective effects are, at least partly, mediated by the inhibition of P2Y12-dependent microglia activation and chemotaxis.
