Migraine-like phenotypes are influenced by age and sex in a mouse model of chronic migraine

Editor’s note: The research described below comes from a recipient of a 2026 MSC Travel Grant supporting travel to the 68th Annual Scientific Meeting of the American Headache Society. These grants reimburse travel expenses for those who have had their abstract for a presentation or poster accepted at a meeting. 

By Kofi Frimpong-Manson, PhD student, Rutgers – The State University of New Jersey.

What is the research gap that your study addresses?

Chronic migraine affects women more than men and its prevalence increase with age, peaking around middle age. But we do not understand why migraine is more common in women or why its prevalence increases with age. Chronic migraine is said to be associated with increased inflammatory cytokine signaling in plasma and the brain. But preclinical studies often do not report sex differences because they use only young adult mice, just one sex (usually female mice), focus on a limited set of cytokines, and analyze samples at the end of the experimental timeline.

What is your research hypothesis?

We hypothesized that using a middle-aged rodent model of chronic migraine of both sexes would improve translational relevance and reveal sex and age differences in cytokine production. We also hypothesized that these differences may be time dependent and more detectable earlier during the chronification of migraine.

What methodology did you use to address your research hypothesis?

We used the nitroglycerin model of chronic migraine. Young adult and middle-aged male and female mice received repeated nitroglycerin or saline injections on alternating days over nine days. We assessed hind paw mechanical allodynia using von Frey filaments at baseline and two hours after each injection, allowing us to measure both persistent and acute sensitivity.

In a separate cohort of mice, we repeated the experiment but conducted locomotion tests, and euthanized the animals on day five, the midpoint of the study. We collected plasma and cortex and used the Luminex multiplex assay to capture a panel of cytokines associated with the innate and adaptive immune system.

What are the main results of your study?

We observed persistent and acute allodynia in young male and female mice. In contrast, in middle-aged mice, there was a sex difference in which females developed allodynia.

Nitroglycerin did not negatively affect the movement of the mice. We observed sex differences in cytokine production. Significant changes were observed only in females in both the young and middle-aged groups. We observed a mixed pattern of site-specific cytokine regulation, with decreases in both pro-inflammatory (IL-17A, IFN-gamma, IL-15) and anti-inflammatory (IL-2) cytokines in the plasma and brain. Pro-inflammatory IL-1 beta was also increased in the plasma of females.

What conclusions did you reach based on your results?

Females may be more susceptible to immune-driven mechanisms that lead to chronic migraine than males. Our findings also suggest chronic migraine may involve dysregulated immune signaling rather than just inflammation. The nitroglycerin middle-aged mouse model of chronic migraine is a promising model that can reveal sex differences in migraine phenotypes.

What are the limitations of your study?

In our work, we applied von Frey filaments to the hind paw, not around the periorbital region of the rodents. We also did not measure cytokines at multiple time points to determine whether sex differences vary across all experimental periods. Lastly, we did not monitor the estrous cycle of the mice because we were interested in cytokine effects, not hormonal effects, in our model.

What is the relevance of your study to migraine?

In my work, I have demonstrated that sex differences in cytokine signaling may explain why migraine affects women more than men. However, further studies are needed to determine whether these cytokine changes are a cause or an effect associated with chronic migraine, while accounting for sampling time. This study encourages the basic science research community to study the effect of aging on migraine pathophysiology.