The Effect of Peripheral Nerve-injury on Depression and Anxiety-like Behaviours in Mice

Past animal studies examining the relationship between depression and chronic pain have used only male rodents and often only assessed behaviours 7 to 14 days after an injury. To determine whether chronic pain results in a sexually dimorphic presentation of depression-like behaviours, I conducted a series of experiments assessing male and female mice at 14, 28, and 42 days after a peripheral nerve injury. I found that mice did not show any changes in behaviours 14 or 28 days. At 42 days post-surgery male mice with a nerve injury showed significantly more depressive-like behaviours than the sham group, however females did not. This suggest that results from male rodents may not be generalizable to females and that studies assessing mental health and chronic pain in rodents should assess behaviour over longer periods of time as to be more representative of long-term pain experiences.M.A