The Effect On The Activity Of The Transcription Factors In Spinal Adorsal Root Ganglion Cells Of Rats After Recurrent Respiratory Syncytial Virus Infection

Objective: On the basis of studying on airway hyperreactivity induced by airway neurogenic inflammation and airway neural plasticity, This project aims to investigate the expression of intracellular transcription factor in the C7-T5 spinal adorsal root Ganglion cells of SD rats after recurrent respiratory syncytial virus (RSV) infection and to identify the key intracellular transcription factors of involving in airway neural plasticity. Thus, to elucidate the mechanism of airway neural plasticity leading to the airway hyperreactivity and bronchial asthma after recurrent respiratory syncytial virus infection.Methods: RSV is inoculated on the Hela cell bespreaded on the culture flask,and harvested when all of cells were infected undermicro-scope.The suspension was kept in reserve at -70℃.The virus-free medium was obtained as a negative control. The virus stock was titrated and diluted as final titer of 5×10⁴ 50% tissue culture infective dose (TCID50)in 0.1ml (virulence determination). Sixty 2-week-old SD rats(Hu Nan Agriculture University ,china) were randomly assigned into two groups (n=30 in each group). A volume of 0.4ml/kg body wt of RSV suspension was inoculated in the nostril of RSV-infected group while the rat was under pentobarbital sodium anesthesia(40mg/kg),control group were administered the same volume of virus-free medium.The treatment . above is repeated once a week.The rats were tested airway responsiveness before sarcrificed at 8th week and the left lung was removed for hema-toxylin and eosin, immunohistochemistry staining. C7-T5 dorsal root ganglion are dissected on the ice surface and put into the cryovial and stored in liquid nitrogen. RSV protein was assayed by hybridization in situ. The expression of SYN and NF in the airway and dorsal root ganglion were assayed by immunohistochemistry and transcription factors in C7-T5 dorsal root ganglion are preliminarily screened by the TranSignal^TM Protein/DNA Combo Arrays.The expression of EGR-1 in lung tissue and C7-T5 dorsal root ganglion were detected by western blot.Results: (1)RSV infected rats gradually showed these syndromes such as catarrhalic rhinitis, gasping, mussy hair and activity decreasing.There was no significant difference between the two groups in the average body weigh. The temperature between the two groups has significant difference (P<0.05). (2)Airway resistance were significantly increased in the model groups than in the normal control group (P<0.05) after inhaled escalating histamine, indicating the airway hyperreactivity existed in RSV infected group. (3) The RSV infected group showed typical interstitial pneumonia under light microscope. (4) Comparing with the rats of control group, the expression of SYN and NF increased significantly (P<0.05) in RSV infected rats. (5) Protein/DNA array analysis showed that the expression of 55 transcription factors increased at least 2 fold in the C7-T5 spinal ganglion cells of RSV infected group, and the expression of 43 transcription factors decreased at least 2 fold in the C7-T5 spinal ganglion cells of the RSV-inoculated group. (6)The expression of EGR-1 was decreased both in the lung and in the C7-T5 spinal ganglion cells after RSV infection.Conclusion: (1)The airway hyperreactivity in rats can be established successfully by RSV nostril inoculation. (2)The airway showed neural plasticity by SYN and NF staining after recurreent RSV infection. (3) TranSignal? Protein/DNA Combo Arrays analysis show that RSV infection result in the expression alteration of 98 transcription factors and build a foundation for futher study. EGR-1 may not be the key intracellular transcription factors of regulating airway neural plasticity.