Isolated closed minor-muscle injury of the lower leg did not cause an obvious systemic immune response

A common consequence in patients with blunt trauma is a deterioration of the immune system. The specific impacts of a frequently occurring isolated soft tissue trauma on the immune response are described. However, the dimension of trauma needed to cause systemic effects has not been definitely elucidated.

Mice were traumatized on the lower leg. The extent of soft tissue trauma was quantified by determination of the wet/dry ratio, magnetic resonance imaging (MRI), and serum content of muscle proteins. Five minutes, 3, 24, 36, 48, and 72 h after trauma (a.t.) the ex vivo cytokine-expression of immune-competent cells were measured.

Trauma resulted in an early edema that could be quantified by MRI and wet/dry ration. Release of muscle-specific proteins was detected 5 min a.t. The trauma did not cause significant changes of TNF-alpha response of isolated cells to endotoxin. IL6-response of splenocytes to endotoxin was slightly increased 72 h a.t., while IL6-response of peritoneal macrophages to endotoxin was decreased 36 h a.t.

We describe a standardized trauma model for minor soft tissue injury in mice. Systemic effects on the immune system by traumatized lower leg were not found on the level of circulating cytokines or cellular responses to endotoxin.