Changes in cell migration and survival in the olfactory bulb of the pcd/pcd mouse

Abstract

[EN]Postnatally, the Purkinje cell degen-eration mutant mice lose the main projecting neurons ofthe main olfactory bulb (OB): mitral cells (MC). Inadult animals, progenitor cells from the rostral migra-tory stream (RMS) differentiate into bulbar interneur-ons that modulate MC activity. In the present work, westudied changes in proliferation, tangential migration,radial migration patterns, and the survival of thesenewly generated neurons in this neurodegeneration ani-mal model. The animals were injected with bromodeoxy-uridine 2 weeks or 2 months before killing in order tolabel neuroblast incorporation into the OB and to ana-lyze the survival of these cells after differentiation,respectively. Both the organization and cellular compo-sition of the RMS and the differentiation of the newly generated neurons in the OB were studied using specificmarkers of glial cells, neuroblasts, and mature neurons.No changes were observed in the cell proliferation ratenor in their tangential migration through the RMS, indi-cating that migrating neuroblasts are only weakly re-sponsive to the alteration in their target region, the OB.However, the absence of MC does elicit differences inthe final destination of the newly generated interneur-ons. Moreover, the loss of MC also produces changes inthe survival of the newly generated interneurons, in ac-cordance with the dramatic decrease in the number ofsynaptic targets available