EFFECTS OF UNLOADING CONDITION ON WOUND HEALING PROCESS: EXPERIMENTS WITH HIRUDO MEDICINALIS.

Wound healing is a fundamental process for survival. It makes an organism able to repair a damage and restore physiological condition. The whole process involves the coordinated interaction of many different cell populations and biochemical molecules, such as proteins, proteases, growth factors, and extracellular matrix (ECM) components. the possibility to carry out research in unloading conditions represents an unique tool to increase our knowledge on wound healing biomechanics and the role of gravity in the process. Moreover, in the perspective of longer-term space missions, with a growing number of astronauts involved, wound healing must be regarded as a serious problem, because the risk of injury due to traumatic events or unexpected emergency surgery will increase while medical evacuation times to Earth will become incompatible with the urgency of implementing assistance procedures. Therefore, it is crucial to understand the impact of microgravity (μg) on the mechanisms underlying wound healing. In the frame of these studies, we developed an in vivo model of wound healing based on leeches [Hirudo Medicinalis]. This invertebrate represents an interesting model, since the sequence of events occurring during the healing is similar as in vertebrates. Moreover, the leech is very resistant and, once nourished, can survive for some months without eating. For this reasons, it can be considered one the most suitable living beings to be used for experiments both in modeled and real μg, even during long-term space missions. The results of preliminary experiments about healing process are iullustrated and discussed