Light deprivation slows but does not prevent the loss of photoreceptors in taurine transporter knockout mice

Taurine transporter knockout mice show severe retinal degeneration at an early age. The study was designed to determine whether degeneration also takes place in the absence of light. Mice were maintained up to 6 weeks of age in cyclic lighting or in total darkness. Degeneration took place in both groups, but was more rapid in animals exposed to standard cyclic illumination. At the ultrastructural level the retinas showed features characteristic of apoptosis but not of necrosis. Conclusions: Cell differentiation is not seriously affected by the lack of a functional taurine transporter but mature photoreceptor cells do not survive without an intact transporter, even in the dark. (C) 2004 Elsevier Ltd. All rights reserved.