Primary Study To The Expressions Of Nogo Gene And The Key Proteins Of Its Signaling Pathways In The Mouse Cochlea

Objective:To investigate the main transcripts of Nogo gene and its possible signaling pathways by observing the expressions of the three transcripts Nogo-A, Nogo-B, Nogo-C and its three receptorsNgR,PirB, GPR50and the amino-Nogo integrina a4,av and a5in the mouse cochlea.Methods:Mice were divided into the following5groups according to their ages:3days,7days,2weeks,4weeks and8weeks. mRNA were extracted from the mouse cochlea by using Trizol, then reverse-transcribed into double-stranded cDNA.Following, Nogo-A, Nogo-B, Nogo-C, NgR, PirB, GPR50and the amino-Nogo integrina a4,av and a5in the cochlea were analyzed by fluorogenic quantitative reverse-transcriptase-polymerase chain reaction (RT-PCR).Results:1. Nogo-A, Nogo-B and Nogo-C were all positive expressed in the mouse cochlea. Analyzing their expressions in3-day-old cochlea, Nogo-A (0.185±0.0070) and Nogo-B (0.175±0.0060) were significantly higher than Nogo-C (0.011±0.0001)(P<0.05). Analyzing the expressions in every group, Nogo-A in3-day-old mouse cochlea (0.185±0.0070) was significantly higher than that of7-day-old group (0.046±0.0025)(P<0.05), no significant difference among the groups of2-week (0.011±0.001)4-week (0.010±0.0009) and8-week (0.009±0.0008)(P>0.05). Also, the expression of Nogo-B in3-day-old mouse cochlea (0.175±0.0060) was significantly higher than that of7-day-old group(0.040±0.0018)(P<0.05), and there were also no significant difference among the groups of2weeks (0.010±0.0010),4weeks (0.009±0.0008) and8weeks (0.009±0.0009)(P>0.05). The expressions of Nogo-A and Nogo-B in3-day groups cochlea were at the highest, and then gradually decreased to an about horizon after2-week-old.However, there were no significant difference of the expressions of Nogo-C in the cochleas among the groups of3days (0.011±0.0001),7days (0.010±0.0008),2weeks(0.009±0.0007),4weeks(0.010±0.0007),8weeks (0.010±0.0008)(P>0.05)2. The three receptors (NgR, PirB, GPR50) of Nogo and the amino-Nogo integrina (a4,av and a5) were all positive expressed in the mouse cochlea. But,in the3-day-old mouse cochleas, there were no significant difference among the expression of NgR (0.011±0.0010),PirB (0.010±0.0008),GPR50(0.009±0.0008),a4(0.011±0.0009),av (0.009±0.0007),a5(0.008±0.0006)(P>0.05).Conclusions:1. Nogo-A and Nogo-B are the mainly expressed transcripts of Nogo gene in the mouse cochlea. Their expressions might be in the highest level in the newborn mouse cochlea, and then decrease to a stable level after2-week-old.2. The signaling pathway Nogo-NgR, Nogo-PirB, Nogo-GPR50and Nogo-amino-integrina might all exist in the mouse cochlea. But which is the priority signaling pathway of Nogo in the mouse cochlea need to be further studied.