Brain injury can be caused by external trauma or internal damage. Animal testing is used to better our understand how to prevent damage to the brain and to repair it after injury.
Brain trauma is typically caused by an impact to the head, for example in a car crash or fall. In these events, the brain can collide with the skull and damage blood vessels. Internal haemorrhaging can lead to parts of the brain being starved of oxygen and a build-up of pressure can cause serious damage. A number of treatments (stem cells, calcium channel blockers, anti-inflammatory drugs, oestrogens, and iron chelators) have shown potential in animal models of intra-cerebral haemorrhage
Animal experiments are also used to determine which techniques are best following traumatic brain injury. Acute therapies such as hypothermia treatment or the use of hypertensives have been shown to reduce brain damage in animal models, and rehabilitation therapies such as a ketogenic diet, exercise and sensory stimulation have also been confirmed through controlled trials with animals .
Research published in 2011 revealed how woodpeckers avoid brain damage when pecking at trees a hundred times per minute. The birds feel forces of up to 1000 g (compared to the 3 g felt by astronauts during a space shuttle launch) yet suffer no damage. CT scans revealed various sections of spongy bone in the skull and altered sizes of bones in the beak that help to prevent injury from impact. This design, refined by nature, could be used to develop more efficient protective headgear for those at risk of head trauma .
Strokes are caused by blood clots that prevent oxygen from reaching parts of the brain. These can be fatal and happen without warning. Please visit our stroke page for more details on how animal research is helping to treat and understand the effects of strokes.
Brain cancer is particularly damaging as it cannot be seen externally and the compact nature of the skull means that tumour growth can put the brain under significant pressure. The most common and deadly form of brain cancer is glioblastoma, with a median survival time of 14 months even with treatment
The brain is protected by a barrier that wraps around the blood vessels which prevents it from being infected by bacteria or viruses in the blood. However, this also makes it difficult for drugs designed to target brain tumours to reach their target. To get around this, researchers have developed a technique using ultrasound to temporarily disrupt the barrier in rats. When this is combined with magnetic nanoparticles containing medicine, a magnetic field can be used to target the drug to the brain tumour . Now Michael Canney and his colleagues have managed to open the blood barrier in humans using an ultrasound brain implant and an injection of microbubbles. When ultrasound waves meet the microbubbles in the blood, they make the bubbles vibrate which pushes the blood-brain barrier's cells apart.
Scientists have also used cancer-killing viruses to target brain cancer in mice . Animal experiments showed that to prevent the viruses from being attacked by the immune system, they were hidden within infected neural stem cells. These cells automatically migrate towards tumours, where the viruses are released and kill the cancer cells.
- Wang L, Cheung JT-M, Pu F, Li D, Zhang M, et al. (2011) Why Do Woodpeckers Resist Head Impact Injury: A Biomechanical Investigation. PLoS ONE 6(10): e26490. doi: 10.1371/journal.pone.0026490
- Johnson DR, O'Neill BP. (2011) Glioblastoma survival in the United States before and during the temozolomide era. J Neurooncol. 107(2):359-64. doi: 10.1007/s11060-011-0749-4
- Marumoto T et al. (2009) Development of a novel mouse glioma model using lentiviral vectors. Nature Medicine 15:110-6. doi: 10.1038/nm.1863
- Liu HL et al. (2010) Magnetic resonance monitoring of focused ultrasound/magnetic nanoparticle targeting delivery of therapeutic agents to the brain. Proc Natl Acad Sci USA 107:15205–15210. doi: 10.1073/pnas.1003388107
- Ahmed AU et al. (2011) Neural Stem Cell-based Cell Carriers Enhance Therapeutic Efficacy of an Oncolytic Adenovirus in an Orthotopic Mouse Model of Human Glioblastoma. Molecular Therapy 19(9):1714–26. doi:10.1038/mt.2011.100