Authors and affiliations:

Huishu Hou,1 Nicole J. Sylvain,1 M. Jake Pushie,1 Julia Newton,2 and Michael E. Kelly1.

1Department of Surgery, College of Medicine, University of Saskatchewan.

2 Department of Anatomy and Cell Biology, University of Saskatchewan


Stroke is associated with age and occurs more frequently in men. Studies show both estrogen and progesterone have neuroprotective effects after a brain injury in females. Other studies using rodents as stroke models reported no significant difference between males and females in stroke recovery.

Using synchrotron-based X-ray fluorescence imaging (XFI) and Fourier transform infrared (FTIR) spectroscopic imaging combined with immunohistochemistry, we identify previously unobserved changes in both the biochemical and elemental distribution in the female brain at different points of the estrus cycle, post-stroke. Vaginal secretions were collected twice daily to track female mouse estrus stages. Photothrombotic stroke surgeries were conducted either at the oestrus (high estrogen and progesterone levels) or diestrus (low hormone levels) estrus stage. Age-matched male mice also underwent stroke surgery for comparison. 24h post-stroke brain were collected and cryo-sectioned for all experiments.

Our results reveal that females have larger infarct size compared to age-matched males. Both XFI and FTIR results show minor differences in biochemical and elemental distribution between females and males, but trends are matched. Studies of sex differences in animal models is vital to understanding the underlying mechanisms of clinically-associated physiological changes in stroke.

Sex differences in a mouse model of focal ischemia: Biochemical and elemental imaging using synchrotron-based techniques