The saline effect: minimizing the severity of brain damage by reduction of secondary degeneration

Rats with bilateral lesions in the caudate nucleus received intracerebral injections of isotonic saline directly into remaining caudate tissue. Compared with noninjected controls, saline-treated animals performed a spatial footshock task better when tested after a 9-day recovery period but not if tested shortly after surgery. Histological evaluation revealed that the saline treatment significantly reduced anterograde degeneration in substantia nigra pars reticulata. In addition, behavioral measures correlated with lesion size and degree of anterograde degeneration in saline-treated animals but not in operated controls. It seems that saline injections can prevent neuronal death in tissue surrounding the zone of trauma, possibly through an alteration of ionic properties in the extracellular space.