碱性成纤维细胞生长因子/绿色荧光蛋白基因对药物性耳蜗损害的防治作用

目的　探讨阳离子脂质体 (天然碱性脂SA)携带碱性成纤维细胞生长因子 /绿色荧光蛋白 (bFGF/GFP)基因在豚鼠耳蜗中的表达 ,以及对庆大霉素所致耳蜗损害的防治作用。方法　将 36只豚鼠分为 3组 ,预防组右耳圆窗注入SA bFGF/GFP复合物后次日肌肉注射庆大霉素 15 0mg·kg-1·d-18天 ,治疗组先用庆大霉素 8d后次日右耳给药 ,对照组单用庆大霉素 8d。分别于实验前后及处死前行听觉脑干诱发电位 (ABR)测试。荧光显微镜下观察耳蜗GFP的表达 ;用耳蜗琥珀酸脱氢酶染色铺片 ,扫描电镜观察毛细胞的缺失情况。结果　荧光显微镜下见双侧耳蜗均有GFP表达。预防和治疗组处死前的双耳ABR阈值与对照组比较差异有显著意义 (P <0 0 1,P <0 0 5 ) ,耳蜗内外毛细胞缺失数与对照组比较差异有显著意义 (P <0 0 1,P <0 0 5 )。结论　SA脂质体介导的bFGF/GFP基因单耳给药双侧耳蜗均有高效表达 ,并对庆大霉素所致的耳蜗损害有防治作用。

Protective and rescue effects of transgenic bFGF/GFP expression mediated by cationic liposome on gentamicin-induced guinea pig cochlear toxicity

OBJECTIVE: To observe the expression of cationic stearylamine (SA) liposome mediated basic fibroblast growth factor/green fluorescence protein (bFGF/GFP) gene in the cochlea of guinea pig, and evaluate the protection and rescue action of bFGF against the damage caused by gentamicin. METHODS: Thirty-six guinea pigs were divided into 3 experimental groups. Prevention group with inoculation of SA-bFGF/GFP complexes through the round window of right ear and injection of gentamicin 150 mg.kg(-1).d(-1) one day after for 8 days and rescue group with injection of gentamicin for 8 days and infusion of SA-bFGF/GFP complexes in the same way on the ninth day, and control group with only injection of gentamicin for 8 days. Auditory brainstem responses (ABR) was measured prior to and after the administration and before the animals were killed respectively. The animals were killed after the experiment and ABR test, and specimens and slices of chochleae were made to examine the absence of outer and inner hair cells. The expression of GFP in cochlea shown by green fluorescence was observed with fluorescent microscopy. RESULTS: Fluorescent microscopy showed green fluorescence in the cochleae of guinea pigs in prevention and rescue groups. There was no significant difference in ABR threshold between the left and right ears of animals in each group before and after experiment, among both ears of animals in the 3 groups before experiment, and between prevention and rescue group groups before killing (all P > 0.05). However, the ABR thresholds in prevention group and rescue group were significantly lower than that in control group before the animals were killed (P < 0.01 and P < 0.05). The average number of lost outer hair cells was 5 106 +/- 299 cells and 5 605 +/- 109 cells in prevention group and rescue group respectively, without a significant difference between them (P > 0.05). The average amount of missing inner hair cells was 301 +/- 64 cells and 487 +/- 92 cells in prevention group and rescue group respectively, without a significant difference between them (P > 0.05), and significantly lower than that in control group (1 062 +/- 67, P < 0.01 and P < 0.05). The average amount of missing outer hair cells in control group was 6 248 +/- 119 cells, significantly higher than that in prevention group (5 106 +/- 299, P < 0.01) and that in rescue group (5 605 +/- 109, P < 0.05). CONCLUSION: SA-liposome mediated bFGF/GFP gene, which was perfused in one ear, can be expressed highly in both cochleae of the guinea pig, and may protect and rescue cochlea against gentamicin ototoxicity.