A new model for studying the effects of Mycobacterium leprae on Schwann cell and neuron interactions

Millions of patients with leprosy suffer from nerve damage resulting in disabilities as a consequence of Mycobacterium leprae infection. However, mechanisms of nerve damage have not been elucidated because of the lack of a model that maintains M. leprae viability and mimics disease conditions. A model was developed using viable M. leprae, rat Schwann cells, and Schwann cell-neuron cocultures incubated at 33degreesC. M. leprae retained 56% viability in Schwann cells for 3 weeks after infection at 33degreesC, compared with 3.6% viability at 37degreesC. Infected Schwann cells had altered morphology and expression of genes encoding cellular adhesion molecules at 33degreesC but were capable of interacting with and myelinating neurons. Cocultures, infected after myelination occurred, showed no morphological changes in myelin architecture after 1 month of incubation at 33degreesC, and M. leprae retained 53% viability. This article describes a new model for studying the effects of M. leprae on Schwann cells.