A fluid percussion model of experimental brain injury in the rat

Abstract

Fluid percussion models produce brain injury by rapidly injecting fluid volumes into the cranial cavity. The authors have systematically examined the effects of varying magnitudes of fluid percussion injury in the rat on neurological, systemic physiological, and histopathological changes. Acute neurological experiments showed that fluid percussion injury in 53 rats produced either irreversible apnea and death or transient apnea (lasting 54 seconds or less) and reversible suppression of postural and nonpostural function (lasting 60 minutes or less). As the magnitude if injury increased, the mortality rate and the duration of suppression of somatomotor reflexes increased. Unlike other rat models in which concussive brain injury is produced by impact, convulsions were observed in only 13% of survivors. Transient apnea was probably not associated with a significant hypoxic insult to animals that survived. Ten rats that sustained a moderate magnitude of injury (2.9 atm) exhibited chronic locomotor deficits that persisted for 4 to 8 days. Systemic physiological experiments in 20 rats demonstrated that all levels of injury studied produced acute systemic hypertension, bradycardia, and increased plasma glucose levels. Hypertension with subsequent hypotension resulted from higher magnitudes of injury. The durations of hypertension and suppression of amplitude on electroencephalography were related to the magnitudes of injury. While low levels of injury produced no significant histopathological alterations, higher magnitudes produced subarachnoid and intraparenchymal hemorrhage and, with increasing survival, necrotic change and cavitation. These data demonstrate that fluid percussion injury in the rat reproduces many of the features of head injury observed in other models and species. Thus, this animal model could represent a useful experimental approach to studies of pathological changes similar to those seen in human head injury.

Modelos experimentales de traumatismo craneoencefálico

“…El impacto del fluido sobre la corteza produce un desplazamiento del cerebro que determina fuerzas de tensión en el tejido cerebral, tratán-dose de un modelo de mecánica compleja. Los primeros modelos de percusión por fluido, desarrollados en gatos y conejos 49,103 y posteriormente en ratas 30,78 , consistían en la aplicación de un impacto sobre la línea media del cerebro. Posteriormente la localización del impacto fue modificada, para producir un daño focal en un solo hemisferio, denominándose modelo de LFP 79 .…”

“…El principal hallazgo neuropatológico observado consiste en una contusión cortical a nivel del sitio del impacto en la interfase entre sustancia gris y blanca, que llegará a convertirse en una cavidad necrótica pasadas unas semanas del traumatismo 28, 44 . Además se observan hemorragias petequiales en el parénquima cerebral (que pueden variar desde pequeños focos hemorrágicos dispersos a áreas hemorrágicas confluentes), lesión axonal difusa bilateral 17,18 , hemorragia subaracnoidea y muerte celular a nivel de la corteza, hipocampo y tálamo ipsilateral 17,18,27,28,50,99. Las principales ventajas de este modelo son su alta reproducibilidad y la capacidad de producir un daño cerebral de diferente grado de severidad según la intensidad del trauma 30,31 . Además puede emplearse con ratones, permitiendo la investigación en animales knockouts o con hiper-expresión de un gen particular 17 .…”

Acute vitreoretinal trauma and inflammation after traumatic brain injury in mice

“…A pendulum was released, hitting a saline‐filled reservoir, which produced a fluid pressure wave that impacted the dural tissue and brain parenchyma through a craniectomy (Fig. 1C) 16, 25, 26. As a result of impact by the fluid wave, there was significant destruction of cortical tissue and disruption of the blood–brain barrier (BBB) at the injury site as detected by immunohistochemistry staining for mouse IgG 24 h post LFPI (arrows in Fig.…”

“…The lateral fluid percussion injury (LFPI) model was modified from a previously described model 25, 26. Four‐month‐old wild‐type C57BL/6 mice were assigned to either the LFPI ( n = 4) or the sham ( n = 3) group.…”

Electrical stimulation improved cognitive deficits associated with traumatic brain injury in rats

“…The fluid percussion injury (FPI) model is a broadly used animal model of closed brain injury (Dixon et al., 1987). Briefly, the rats were anesthetized with 10% chloride hydrate (3.0 ml/kg, intraperitoneal injection) and placed in a stereotaxic frame.…”