Respiratory responses following blast-induced traumatic brain injury in rats

• Blast overpressure (OB) injury in rodents has been employed for modeling the traumatic brain injury (TBI).
• This study investigated the effect of OB pressure and repeat injury on breathing pattern before, during and after OB injury.
• Diaphragm electromyographic recordings in chronically instrumented animals revealed OB induced apnea.
• Respiratory apnea and phase timing increased with increasing OB pressure and second exposure to OB.
• Dorsal directed, closed-head OB injury results in a neurally mediated apnea followed by respiratory timing changes.

Blast overpressure (OB) injury in rodents has been employed for modeling the traumatic brain injury (TBI) induced by an improvised explosive device (IED) in military service personnel. IED's can cause respiratory arrest if directed at the thorax due to the fluid–tissue interface of the lungs but it is unclear what respiratory changes occur in a head-directed OB injury. The diaphragm is the primary muscle of inspiration and electromyographic (EMG) recordings from this muscle are used for recording breathing in anesthetized and conscious rats. The breathing pattern of the rodents will be recorded during the OB injury. Our results indicate that a dorsal directed closed-head OB injury results in a neurally mediated apnea followed by respiratory timing changes.