Prior cigarette smoke exposure does not affect acute post-stroke outcomes in mice

Area of Science:

• Pulmonary Medicine
• Neurology
• Toxicology

Background:

• Chronic obstructive pulmonary disease (COPD) is a leading global cause of death, strongly linked to cigarette smoking.
• COPD is a recognized risk factor for cardiovascular events and stroke.
• The impact of COPD on stroke severity remains unexplored.

Purpose of the Study:

• To investigate if cigarette smoke (CS) exposure exacerbates stroke outcomes in a mouse model.
• To assess functional and histological stroke endpoints in mice exposed to CS before transient middle cerebral artery occlusion (tMCAO).

Main Methods:

• Mice were exposed to room air or CS for 2, 8, or 12 weeks.
• Following exposure, mice underwent tMCAO or sham surgery.
• Bronchoalveolar lavage fluid (BALF), lungs, and brains were collected 24 hours post-surgery for analysis.

Main Results:

• CS exposure led to increased inflammatory cells (total cells, neutrophils, lymphocytes, macrophages) in BALF, particularly after 8 and 12 weeks.
• Stroke induction did not further increase CS-induced BALF inflammation.
• No significant differences were observed in neurological deficit scores, foregrip strength, infarct, or edema volumes between CS-exposed and air-exposed stroke groups.

Conclusions:

• Cigarette smoke exposure induces significant pulmonary inflammation in mice.
• Despite pulmonary inflammation, CS exposure did not worsen acute stroke outcomes in this mouse model.
• This suggests that the increased stroke risk in COPD patients may not correlate with increased stroke severity.