An in Vitro Model of Oligodendrocyte Destruction by Nitric Oxide and Its Relevance to Multiple Sclerosis

There is mounting evidence that nitric oxide (NO) is produced in the brains of patients with multiple sclerosis (MS) and in the experimental model of MS, experimental autoimmune encephalomyelitis, after the induction of Type II nitric oxide synthase (iNOS). Because NO can cause a variety of biological insults that compromise or even kill normal cells, we studied the effects of NO on oligodendrocytes since they are a target in MS tissue. In an in vitro model, we have been able to demonstrate that NO causes damage to oligodendrocytes preferentially, sparing microglia almost completely and affecting some but not all astrocytic functions. This article describes the types of assays used to measure morphological changes, mitochondrial dysfunction, DNA strand breaks, and cell death brought on by NO or peroxynitrite (ONOO-) as well as a comprehensive review of the various techniques and sensitivities of NO and iNOS assays that would be applicable to similar in vitro models.