Age-related Changes Of Auditory Function And Expression Of P75 In Cochlea Of The Senescence Accelerated Mouse, Experiment Study On NGF Transfected Into BMSC

Objectiv: To probe age-related changes of auditory function and expression of p75 in cochlea of the senescence accelerated mouse, and to provide support for the experimental research of bone marrow stromalstem cell transduced with NGF cochlea transplantation for treatment of presbycusis.Methods: We choose SAMP8 for the study,each six of 3, 5, 7th month. We detect the auditory brainstem respons(ABR); the p75 immunohistochemical in the coclear, then measuring the optical density value. The transfected cells were divided into four groups: A is recombinant plasmid group, B is the liposome group, C is the empty plasmid group, D is negative control group. NGF-containing plasmid was transfected into BMSC by liposome. after 48 hours, The BMSCs were fixed in 4% paraformaldehyde, then we use the immunohistochemical to analyze the expression of NGF、p75 in cells.Results: 1. ABR thresholds of mice was increased with the increase of age, there were significant differences between the groups(P<0.05). 2. There were p75 increased expressed in the cochlea of each mouse with the increase of age, there were significant differences between the groups(P<0.05). 3. There were NGF/p75 expressed in the cytoplasm of BMSC of each group, the expression of NGF of recombinant plasmid group is the most obvious, while the expression of p75 is contrary, which showed significant differences between other three groups(P<0.05).Conclusions: The expression of p75 increases with the age-related hearing loss of the mouse. This indicates that p75 may be involved in mediating the process of cochlear dysfunction. The transfected p75 can low expression in BMSCs, probably because after transfection, NGF may have obvious inhibitory on the expression of p75, so the expression of p75 decreased obviously. Maybe Provides new possibilities for gene therapy of presbycusis...