Gene transfection mediated by polyethyleneimine-polyethylene glycol nanocarrier prevents cisplatin-induced spiral ganglion cell damage.

Polyethyleneimine-polyethylene glycol (PEI-PEG), a novel nanocarrier, has been used for transfection and gene therapy in a variety of cells. In our previous study, we successfully carried out PEI-PEG-mediated gene transfer in spiral ganglion cells. It remains unclear whether PEI-PEG could be used for gene therapy with X-linked inhibitor of apoptosis protein (XIAP) in the inner ear. In the present study, we performed PEI-PEG-mediated XIAP gene transfection in the cochlea of Sprague-Dawley rats, via scala tympani fenestration, before daily cisplatin injections. Auditory brainstem reflex tests demonstrated the protective effects of XIAP gene therapy on auditory function. Immunohistochemical staining revealed XIAP protein expression in the cytoplasm of cells in the spiral ganglion, the organ of Corti and the stria vascularis. Reverse transcription-PCR detected high levels of XIAP mRNA expression in the cochlea. The present findings suggest that PEI-PEG nanocarrier-mediated XIAP gene transfection results in XIAP expression in the cochlea, prevents damage to cochlear spiral ganglion cells, and protects hearing.

[Application of ultracision-harmonic scalpel for tonsillectomy].

OBJECTIVE: To investigate the advantages and disadvantages of ultracision-harmonic scalpel assisted tonsillectomy by compared with conventional tonsillectomy. METHODS: Eighty-eight patients were randomly divided into ultrasonic scalpel group (group A, 42 cases) and control group (group B, 46 cases). The tonsillectomy in group A was performed with ultracision-harmonic scalpel, and in group B, the tonsillectomy was performed by routine method. The surgical time (complete removal of tonsils), blood loss, and postoperative sore throat situation were recorded. RESULTS: Surgical time in group A [(14.7 ± 4.0) min] was shorter than that in group B [(28.9 ± 7.6) min], t = -10.691, P < 0.05. Blood loss in group A [(3.1 ± 1.1) ml] was less than that in group B [(19.0 ± 5.2) ml], t = -19.544, P < 0.05. Postoperative sore throat was less painful in group A than that in group B in 10 hours after surgery, but much painful than group B 3 days after surgery and most patients lasted longer. There were statistical differences (P < 0.05). The average peel off time for the tunica albuginea was 8 days after the operation by using traditional method, by compared with the ultrasonic scalpel method, average time was 11 days, the difference showed statistical significance (t = 5.115, P < 0.05). CONCLUSIONS: Compared with traditional tonsillectomy, ultracision-harmonic scalpel tonsillectomy had shorter operative time, less blood loss and so on, but the sore throat symptoms persisted longer. In addition, the tunica albuginea peeled off later, so avoidance of secondary bleeding caused by improper diet was mandatory.

[Effect of brain-derived neurotrophic factor gene transfected bone-marrow mesenchymal stem cells on damaged cochlear spiral ganglion cells of guinea pigs].

OBJECTIVE: To investigate the protective role of brain-derived neurotrophic factor (BDNF) gene transfected bone-marrow mesenchymal stem cells (BMSC) on cochlear spiral ganglion cells (SGC) impaired by aminoglycoside antibiotics (AmAn). METHODS: The differentiation of BMSC transfected by BDNF gene (BDNF-BMSC) were detected with immunohistochemical examination of Nestin, neuron-specific enolase (NSE), and glial fibrillary acid protein (GFAP) antibody in vitro. BDNF gene transfected BMSC were transplanted into the cochleae of guinea pigs deafened by amikacin, while the control groups were designed in which artificial perilymphatic fluid (APF), BMSC or BDNF gene was injected into cochleae alone. The cochleae were obtained on the week 1, 2 and 4 after injection, respectively, paraffin-embedded, and cut in a paramodiolar plane subsequently. The histopathological changes of cochleae were observed, the density of SGC was calculated by staining with HE, and the corresponding optical density (COD) was calculated with immunohistochemical staining using NSE antibody. And the protective role of various groups on the cochlear SGC were compared. RESULTS: The positive staining rate of BDNF gene transfected BMSC with Nestin, NSE and GFAP antibody were all higher than that of BMSC in vitro (P < 0.01). After transplantation into cochleae, the differences of SGC density and COD among various groups were all significant on the same time points (P < 0.05). The SGC density and COD of the BDNF gene transfected BMSC group were the highest. The SGC density and COD of various groups on week 4 were all obviously decreased than those on week 1 and 2 (P < 0.05). CONCLUSION: AmAn-induced SGC damage could be depressed by BMSC, BDNF gene or BDNF gene transfected BMSC transplantation into cochleae, while BDNF gene transfected BMSC showed the best protective role.

[Expression of brain-derived neurotrophic factor modified bone marrow mesenchymal stem cells in the cochlea of drug deafened guinea pigs and its protection role].

OBJECTIVE: To study the expression of brain-derived neurotrophic factor (BDNF) gene modified bone marrow mesenchymal stem cells (MSC) in the cochlea of drug-deafened guinea pigs and its protection to spiral ganglion cells (SGC). METHODS: Guinea pigs deafened by subcutaneous injection of amikacin were randomly divided into two groups, BDNF gene modified bone marrow MSC were injected into the cochlea through fenestration of scala tympani in the experimental group, while artificial perilymphatic fluid were injected in the control group. Experimental animals were executed at 7 and 28 days post-operation. Expression of BDNF mRNA was examined by quantitate real time RT-PCR, histological images of cochlear sections were analyzed to calculate the cellular density of the SGC, and terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) was used to identify the apoptotic neurons. RESULTS: The BDNF expressive level in experimental group was higher than in the control group at 7 d and 28 d post-operation, whose differences were both statistically significant (P < 0.01). And, It showed a higher abundance of ganglion cell numbers, as well as a decreased apoptotic index in experimental group compared with the control group at 7 d and 28 d post-operation, whose differences were all statistically significant (P < 0.01). CONCLUSION: BDNF gene modified MSC could maintain expression for at least 28 days after transplantation into cochlea of drug deafened guinea pigs, and protect SGC.