The role of hexon in egg drop syndrome virus (EDSV) inducing apoptosis in duck embryo fibroblast cells.

Although extensive efforts have been made to understand adenovirus infection in human cells, little is known for egg drop syndrome virus (EDSV) infection in the avian-derived cells. In this study, the effects of EDSV infection as well as the possible role hexon protein, the main building block of the EDSV capsid, on apoptosis induction in duck embryo fibroblast (DEF) cells was examined. Flow cytometry analysis and TUNEL assay revealed that EDSV infection induced significant apoptosis in DEF cells compared with mock infected cells. Interestingly, the increase of the apoptosis rate detected in EDSV infected DEF cells were accompanied by an increased virus load in cells in a time-dependent manner. Furthermore, a time-dependent decrease in hexon protein expression levels in hexon transfected DEF cells in parallel with a gradual decrease in TUNEL-labeling cells was also observed in the current study. In addition, caspase activity detection and western blot analysis indicates that either EDSV infection or EDSV hexon transfection both induced apoptosis of DEF cells via activating both the exogenous and the mitochondrial pathway.

[Effect of adenovirus expressing NGF on sciatic nerve injury in rats].

OBJECTIVE: To construct adenovirus expressing NGF (Ad-NGF) and to investigate its promotive effect on the reparation and regeneration of sciatic nerve injury in rats. METHODS: NGF gene sequence was cloned into shuttle plasmid pCA13 of adenovirus type 5. After packed in HEK-293 cells, the recombinant adenoviruses-Ad-NGF underwent sequence identification. Thirty-two male SD rats weighing 180-200 g were randomly divided into 4 groups (n = 8 rats per group). Sciatic nerve injury model was established by disconnecting and direct suturing the right sciatic nerve in the rat. The right gastrocnemius muscle of group A and C received Ad-NGF injection and adenovirus vector without NGF gene sequence injection, respectively, and 1 x 10(8) PFU/per time was given every other day for three times. Group B and D received NGF injection (200 U/d) and normal saline (100 microL/d), respectively, for 3 weeks. The effect of various treatments on injured sciatic nerve was evaluated by performing sciatic nerve function index and nerve electrophysiology detections 31 days after operation. Meanwhile, the sciatic nerve in the anastomosis and at the site 1 cm distal to the anastomosis were obtained, and underwent RT-PCR and Western blot analysis for detecting NGF mRNA and protein expression level in the injured sciatic nerve in the rats. Histology, immunohistochemistry, and transmission electron microscope observations were conducted. RESULTS: Ad-NGF carrying NGF gene sequence was constructed successfully and confirmed by sequence analysis. The sciatic nerve function index, nerve conduction velocity, evoked potential amplitude, and latent period of group A was better than those of other groups (P < 0.05), and there were no significant differences among group B, C, and D (P > 0.05). RT-PCR and Western blot detection: the expression levels of NGF mRNA and protein in group A were greater than those of group B, C, and D (P < 0.05), and no significant differences were noted among group B, C, and D (P > 0.05). Histology and immunohistochemistry observation showed that the regeneration of the sciatic nerve in group A was obvious superior to that of other groups. Transmission electron microscopy observation suggested there was significant difference between group A and groups B, C, and D in terms of axonal diameter of sciatic nerve cross-section, myelin sheath thickness and nerve fiber number (P < 0.05), and there were no significant differences among group B, C, and D (P > 0.05). CONCLUSION: Ad-NGF can effectively promote the repair of sciatic nerve injury in rats, and is a new method for obtaining large amounts of NGF in the area of injured peripheral nerve.