DELAYED NEURITE REGENERATION AAD ITS IMPROVEMENT BY NERVE GROWTH-FACTOR (NGF) IN DORSAL-ROOT GANGLIA FROM MRL-LPR LPR MICE IN-VITRO/

We studied neurite regeneration in MRL-lpr/lpr mice, a murine model of systemic lupus erythematosus, using a culture system to investigate t he influences of immunological abnormalities on neurons. The regenerat ion of cultured dorsal root ganglion (DRG) neurons from MRL-lpr/lpr mi ce was delayed compared with control MRL-+/+ mice. This modification o f regeneration was age-dependent. MRL-lpr/lpr mice older than 16 weeks of age exhibited less neurite regeneration than controls but those yo unger than 6 weeks of age showed equal regeneration. Regeneration was improved by adding nerve growth factor (NGF) to culture medium. Follow ing immunocytochemical staining, we counted the low affinity NGF recep tor p75-positive DRG neurons in MRL mice. The percentage of p75-positi ve neurons in MRL-lpr/lpr mice older than 16 weeks of age was higher t han that in MRL-+/+ mice. These neuronal abnormalities were thought no t to be directly dependent on the genetic defect of Fas antigen, which is related to apoptosis in MRL-lpr/lpr mice, but to be the result of immunological abnormalities. The present study is the first to demonst rate a modification of neurite regeneration by immunological dysfuncti on in autoimmune mice. (C) 1997 Elsevier Science B.V.