Animal models are useful for research in many diseases, including cerebral palsy. Conditions can be controlled with precision, but you can never be certain whether the results of an animal experiment apply to people. Regardless of the uncertainty, the results can be interesting.
Perhaps the most common animal model of cerebral palsy is the so-called hypoxic-ischemic encephalopathy (“HIE”) model in rats. This model has been around about 30 years and is relatively inexpensive to set up. Essentially, the scientist ties off one of the carotids of a week-old rat, then exposes it to low levels of oxygen. The specific protocol may vary a bit in different laboratories, but the model produces a fairly consistent brain injury and most of the young rats survive. Researchers have employed the HIE model to test many different treatment options for cerebral palsy, from stem cells to hyperbaric oxygen.
Dr. John H. Zhang, of Loma Linda University Medical Center, has published a lot of work in the area of hyperbaric oxygen therapy in the HIE model. Much of this work centers around the protective effects of oxygen treatment. For example, a single hyperbaric oxygen treatment following the exposure to low levels of oxygen in the HIE model resulted in a substantial reduction in brain cell death and brain atrophy and even improved motor and sensory function some 6 weeks later.
It is just about impossible to argue with these results. You can criticize the human trials of hyperbaric oxygen in cerebral palsy by saying that the benefits are due to “group participation effect” or some other fancy term for selection bias. But, you cannot dismiss an animal study with standard clichés. Plainly, hyperbaric oxygen can reduce brain injury in the HIE model. Obviously, this model has limitations, but it’s what we have.