Post-Stroke Recovery in Relation to Parvalbumin-Positive Interneurons and Perineuronal Nets.

Area of Science:

• Neuroscience
• Neuroplasticity
• Stroke Recovery Research

Background:

• Spontaneous behavioral recovery after stroke occurs during a critical neuroplasticity window.
• This heightened plasticity may be influenced by reduced inhibitory signaling from parvalbumin-positive (PV+) interneurons and the loss of perineuronal nets (PNNs), which stabilize synapses.

Purpose of the Study:

• To investigate the association between behavioral recovery following stroke and changes in the densities of PV+ interneurons and PNNs.
• To elucidate the spatial-temporal profiles of PV+ interneurons and PNNs in the cortex after stroke.

Main Methods:

• Male Sprague-Dawley rats received forelimb motor cortex stroke or vehicle injections.
• Motor function was assessed using behavioral tests.
• Immunofluorescent labeling was used to quantify PNNs (WFA+ cells), PV+ interneurons, and co-labeled cells in ipsilesional and contralesional cortices at various time points post-stroke (days 1, and 1, 2, 4, 6 weeks).

Main Results:

• A significant decrease in PV+ interneuron density was observed at 1-day post-stroke in the lateral ipsilesional cortex.
• PNN density was significantly reduced up to 4 weeks post-stroke in the lateral ipsilesional cortex and at 1-2 weeks in the medial ipsilesional cortex.
• The reduction in combined PV+/PNN signaling correlated with spontaneous behavioral recovery.

Conclusions:

• Post-stroke behavioral recovery is associated with an early reduction in PV+/PNN co-labeled cells.
• This recovery also involves a temporally dependent decrease in PV+ interneuron signaling and a chronic loss of PNNs.
• Targeting PNNs or PV+ interneuron signaling presents potential therapeutic strategies for extending the stroke recovery window.