碱性成纤维细胞生长因子对耳蜗螺旋神经节细胞谷氨酸钠毒性作用的影响

Effect of basic fibroblast growth factor on cultured spiral ganglion cells following glutamate treatment

目的了解谷氨酸钠致单离培养的小鼠耳蜗螺旋神经节细胞损伤后，碱性成纤维细胞生长因子（ｂＦＧＦ）对其生存及生长的影响，以及二者对细胞内游离钙离子浓度的影响。方法在培养液中加入２×１０２ｍｏｌ／Ｌ的谷氨酸钠２小时后，实验组分别换成含ｂＦＧＦ２５、５０、１００μｇ／Ｌ的培养液，对照组加空白培养液。结果２４小时后可见部分细胞裂解、死亡，对照组明显多于实验组。培养１４天后甲苯胺蓝染色证实，实验组的细胞生存数及细胞突起长度明显高于对照组，差异有显著性（Ｆ检验，Ｐ＜０．０１），且随着ｂＦＧＦ浓度增加，细胞生存数及细胞突起长度均增加，不同浓度实验组间差异有显著性（Ｐ＜０．０１）。用Ｆｌｕｏ３染色，激光扫描共聚焦显微镜观察１０个螺旋神经节细胞，培养液中加入谷氨酸钠后细胞内钙离子浓度迅速上升，在１０～１５秒内达峰值，１００秒左右恢复到正常水平；加入ｂＦＧＦ后细胞内钙离子浓度无明显变化（ｔ检验，Ｐ＝０．２０４）。结论谷氨酸钠可致螺旋神经节细胞内钙离子浓度升高，ｂＦＧＦ可以降低谷氨酸钠对螺旋神经节细胞的细胞毒性。

Objective To understand the effects of basic fibroblast growth factor (bFGF) on survival and neurogenesis of the cultured spiral ganglion cell (SGC) of mouse after exposed to glutamate, and the effects of bFGF and glutamate on free intracellular calcium ion concentration. Methods After exposed to 2×10 -2 mol/L glutamate for 2 hours , the medium of SGC was replaced with the media containing 25,50, 100 μg/L bFGF. Medium without bFGF was used as control. Results Twenty four hours later, more cells in the control group showed signs of cell death than in bFGF groups. After 14 days, specimens were fixed in 4% paraformaldehyde and stained with toluidine blue. It was shown that the SGC in medium with bFGF exhibited more survival and longer neurites, and the effect was dose dependent ( P <0.01). Application of glutamate to the medium induced an increase to the the free intracellular calcium ion concentration in SGC, but bFGF had no such effect. Conclusion Glutamate excitotoxicity was associated with free intracellular calcium ion concentration elevation in SGC, and bFGF could protect SGC against glutamate neurotoxicity.