OBJECTIVETo investigate the specific T cell subpopulation and the relationship with facial motoneuron in immune deficiency mouse model with facial nerve paralysis, so as to find information for new strategy of facial palsy treatment.

METHODSFirstly, purifying the CD4+ T cell from wild type mouse and reestablishing the immune function of nude mouse by infusing the CD4+ T cell through the tail vein a week before the surgery. Then the all nude mouse (BALB/c background) and wild type mouse (BALB/c background) were subjected to a right facial nerve axotomy. Then the mouse was studied by application and assessment with fluorogold retro tracer at specific time. After collecting the slices of brain stem three days post the operation, the facial motoneurons was observed under fluorescence microscope, then analyzed and counted with the software Image Pro Plus5. 1.

RESULTSThe number of survival facial motoneuron in the group with CD4+ T cell transplantation and control group was (3444.5 +/- 84.2, x +/- s) and (3013.2 +/- 65.3) respectively. There was significant difference of the number of survival facial motoneurons between nude mouse transplanted with CD4+ T cell and PBS at three days post the operation (t = 5.52, P = 0.0003). But there was no significant difference of survival facial motoneurons between nude mouse transplanted with CD4+ T cell and wild type mouse three days post the operation (t = 0.49, P = 0.6347). It was the transplantation of CD4+ T cell that rescued the survival facial motoneuron to the level of wild type.

CONCLUSIONSCD4+ T cell have the ability to rescue the injuring facial motoneuron from death. It may suggest that there is a critical role of the specific T cell subpopulation in facial nerve repair and regeneration.