藁本内酯通过抑制铁自噬延缓小鼠听皮层组织衰老

Ligustilide delays senescence of auditory cortex in mice by inhibiting ferritinophagy

目的探究藁本内酯(ligustilide,LIG)延缓听皮层组织衰老,治疗中枢性老年性聋的机制。方法将40只13月龄C57BL/6J小鼠随机分为LIG低剂量组(L-LIG)、LIG中剂量组(M-LIG)、LIG高剂量组(H-LIG)和衰老组(Age),同品系2月龄小鼠10只作为对照组(Ctrl)。听性脑干反应测试检测给药前后小鼠听阈值;检测血清SOD活力和MOD含量了解氧化应激水平;HE染色观察听皮层病理变化;透射电子显微镜观察铁死亡情况;Western blot法检测听皮层组织NCOA4、GPX4和ACSL4蛋白的表达水平;免疫荧光法观察铁自噬情况;普鲁士蓝染色观察听皮层铁蓄积水平。结果衰老组小鼠听阈值明显升高,并表现出明显的衰老与铁死亡特征。中、高剂量LIG干预降低小鼠听阈值,改善听皮层组织病理损伤,保护神经元线粒体形态结构,减少铁聚集颗粒细胞数量,抑制铁自噬,降低NCOA4、ACSL4蛋白表达,升高GPX4的蛋白表达。结论LIG可以通过抑制铁自噬,减少衰老小鼠听皮层神经元铁死亡,延缓听皮层衰老,提示LIG具有治疗中枢性老年性聋的作用。

Aim To investigate the mechanism of ligustilide(LIG)in delaying the senescence of auditory cortex and treating central presbycusis.Methods Forty C57BL/6J mice aged 13 months were randomly divided into ligustilide low-dose(L-LIG)group,ligustilide medium-dose(M-LIG)group,ligustilide high-dose(H-LIG)group and aging(Age)group,and 10 mice aged 2 months of the same strain were used as the control(Ctrl)group.Auditory brainstem response test was used to detect the auditory threshold of mice before and after treatment.Levels of serum MDA and activity of serum SOD were detected to display the level of oxidativestress.The pathological changes of auditory cortex were observed by HE staining.Ferroptosis was observed by transmission electron microscope.The expression levels of NCOA4,GPX4 and ACSL4 in auditory cortex were detected by Western blot.Ferritinophagy was observed by immunofluorescence.The level of iron accumulation in auditory cortex was observed by Prussian blue staining.Results The auditory threshold of mice in Age group increased significantly,and showed obvious characteristics of senescence and ferroptosis.Medium and high doses of LIG treatment decreased the auditory threshold of mice,improved the pathological injury of auditory cortex,protected the ultrastructure of neuronal mitochondria,reduced the number of iron aggregation granular cells,inhibited ferritinophagy,reduced the expression of NCOA4 and ACSL4,and increased the expression of GPX4.Conclusions By inhibiting ferritinophagy,LIG can reduce the ferroptosis of auditory cortex neurons in aging mice,thus delaying the senescence of auditory cortex.It is suggested that LIG has the effect of treating central presbycusis.