Substance P-induced changes in cell genesis following diffuse traumatic brain injury

Area of Science:

• Neuroscience
• Pharmacology

Background:

• Substance P (SP) activity via NK1 receptor antagonists shows neuroprotective potential after traumatic brain injury (TBI).
• Conversely, SP may stimulate neurogenesis, aiding TBI recovery.
• This study investigates SP and NK1 antagonist n-acetyl tryptophan (NAT) effects on cell proliferation post-TBI.

Purpose of the Study:

• To characterize the effects of SP and NAT on cell proliferation following diffuse TBI.
• To determine if SP or NAT influence neurogenesis or microglial activity.

Main Methods:

• Adult male Sprague-Dawley rats underwent TBI using the impact acceleration model.
• Rats were assigned to sham, vehicle control, NAT alone, SP alone, or SP with NAT groups.
• Cellular proliferation was assessed using bromodeoxyuridine (BrdU) immunostaining and cell-specific markers.

Main Results:

• SP infusion (with or without NAT) increased cellular proliferation in the subventricular zone and dentate gyrus post-TBI.
• This proliferation increase was primarily associated with microglial cells.
• No corresponding functional improvements were observed with SP infusion.

Conclusions:

• NAT treatment may offer neuroprotection following TBI.
• This neuroprotection appears partly mediated by the inhibition of microglial proliferation.
• SP's role in TBI recovery may be complex, potentially involving microglial activation.