Development of a Rat Model for Studying Blast-induced Traumatic Brain Injury and the Neuroprotective Effect of Emodin on It
|School||Third Military Medical University|
|Keywords||Emodin Craniocerebral explosive blast injury Neuron-specific enolase Traumatic brain edema|
Since the background and purpose of the Second World War, especially in the outbreak of the Gulf War as a symbol of high-tech local wars, explosive weapons gradually become the main weapon in modern warfare [1-4]. The explosive weapons lethality caused by craniocerebral explosive impact injuries accounted for 70 to 90% of all brain injury, limbs injury incidence after war, the mortality rate of approximately 30 to 40% [5-7]. Explosive weapons hurt injury factor is many with multiple injuries, multi-site injury, combined injury, re-injury and other characteristics. Therefore, the strengthening of explosive weapons injury characteristics and treatment research, especially craniocerebral explosive blast injury treatment has important practical significance [8-9]. But how to build a stable brain explosion blast injury animal models but also to enable the survival time is long enough so that it can continue to observe after injury, pathological, physiological changes, as well as to explore the treatment method is a thorny issue, scholars at home and abroad, such as Nakagawa [10 The explosion blast injury early visible brain tissue was swollen and bulging bone window, from the light microscope observation that brain tissue injury early pathological changes in cerebral vasodilation, 12 hours later in the extracellular space and vascular damage around the center to see widening of the extracellular space, cell volume increases, the the stain fades brain edema [12,13]. Evans blue extravasation injury early injury center scholars Evans blue blood - brain barrier permeability determination, but its scope is far smaller than the light and electron microscope examination revealed cerebral edema scope is limited to damage the central area. The explosion blast injury to prove that early trauma-induced damage is more limited, late seen damage from secondary brain injury [14-16]. More complex mechanisms of secondary brain injury [17-19]. Currently considered brain damage late expand the scope and severity of ischemia and hypoxia may be associated with neurons and glial cells the secondary cytotoxic cerebral edema caused by the release of inflammatory mediators [20-21]. The conventional wisdom is that calcium overload is the final common pathway of death of neurons. Excitatory amino acids (EAA) and the presynaptic membrane membrane potential is regarded as the main reason. For reducing the EAA, and membrane potential of the presynaptic membrane, reducing neuronal excitability is correct Ca2 overload, to prevent secondary brain injury research focus [23,25-27]. Emodin rhubarb important component of the anti-inflammatory, hemostatic, swelling, widely used in the treatment of traumatic brain injury, constipation, jaundice, gastrointestinal bleeding. Previous study found the rhubarb mixture of clinical treatment of brain injury have a significant effect, found significant effect reduce intracranial pressure; recent study found that emodin isolated hippocampal neurons with a wide range of inhibition, can reduce the excitability  Some scholars have used the method to study intracellular recording emodin in rat pyramidal neurons of the hippocampus in the brain slices yuan excitatory postsynaptic potential (EPSP) significantly suppressed for a long period of time in vitro culture; prove to extracellular recording method of emodin on mouse brain slices in vitro culture the population spikes hippocampus significantly inhibited hippocampus optical membrane potential conduction significantly inhibited [22,30]. Experiments found that to emodin point of action is located in the presynaptic membrane and the presynaptic inhibition to reduce the release of neurotransmitters, effectively blocking excitability conduction, thereby reducing the amplitude of the EPSP reaches inhibition. Optional emodin as a tool for drug intervention studies. The purpose of this experiment is to explosion blast injury through the establishment of a stable small animal model to observe changes in vital signs in rats, histopathological examination of brain tissue to detect signs of brain edema cerebral water content, as well as signs of the extent of brain tissue damage neuron-specific sexual enolase (NSE) [17-18]; emodin as a tool for drug body brain cerebral protective effects of blast injury and to explore its possible mechanism of action, provides a theoretical basis for clinical application. Method 1. Establishment of rat brain explosion blast injury animal model; rats were anesthetized by intraperitoneal injection with 1.5% sodium pentobarbital 1ml fixed, the limbs and head in aluminum box animal protection cabin was orthostatic backed by protection cabin sidewalls, regulation of rat location and on the side wall round explosion window, make the the rat frontoparietal occipital All in explosion window, trunk and eyes below the foramen magnum the canthus the connection above orofacial fully protection, 400mg equivalent paper electric detonator placed explosion window of the center distance of 10cm at the level of the side to detonate injury. Observed emodin explosion blast injury intervention role of head: 78 adult SD rats were randomly divided into the of emodin treatment group (n = 36), model control group (n = 36) and normal control group (n = 6). Model control group and emodin treatment group rat brain explosion blast injury model, intraperitoneal injection of emodin treatment group emodin 10 mg (/ kg · d), model control group injected with saline, after injury, 6 h, 12 h, 1 d, 3 d, 5 d, 7 d each phase point at random from each of six rats observed respiratory, physical activity and other physiological and behavioral changes in the light microscope to detect pathological changes measured serum neuron-specific enolase and enzyme concentration and cortical NSE (NSE) immunohistochemical reaction the number of positive cells in cerebral water content in the damage zone, to emodin treatment group compared with the model group. Results established stable rat brain explosion impact injury animal models: each group after the explosion blast injury immediately respiratory rhythm changes, manifested as transient apnea, breathing deep and slow, gradually speed up after a short period of time, are associated with the extremities convulsions 3-5 seconds, 4 to 6h anesthesia sober listlessness, slow, poor appetite. Injured brain cortex diffuse hyperemia, the frontoparietal cerebral contusion, serious brain hemorrhage, cerebral edema. The light microscope cortex broken capillaries, cells and blood vessels around the gap increases, the nerve fibers the loose discrete, cortical continuity disappear. 2. Emodin on brain explosion blast injury with a clear brain protective effect: the model group and emodin treatment group serum NSE concentration and brain water content after injury compared with blank control group was significantly higher cortical NSE immunohistochemical reaction the number of positive cells than the control group significantly decreased (p lt; 0.01); of emodin treatment group in 1d serum NSE concentration and brain water content compared with the model group at all time points significantly reduce (P lt; 0.05), cortical neurons yuan NSE immunohistochemistry The number of positive cells was significantly increased (p lt; 0.05). Conclusion 1.400mg equivalent the electric detonator paper placed rat head horizontal distance of 10cm detonated injury, the establishment of a stable, reliable, repeatable rat brain explosion impact injury animal models. 2. Emodin can reduce the concentration of serum NSE after injury. 3. Emodin the cortical neurons NSE can increased expression. 4. Emodin reduce cerebral edema. 5. Emodin pathological damage can be reduced, confirmed the explosion in rat brain blast injury has a protective effect.