Mechanism of the mitochondria damage of the nerve cells in mouse after chronic exposure to nano-alumina / 中国药理学与毒理学杂志

ABSTRACT

OBJECTIVE To explore the potential neurotoxicity of nano-alu mina (<50 n m)in vivo, we treated the ICR mouse with the nano-alu mina to investigate the mitochondrial da mage of nerve cells on morphology and function.METHODS Adult male mice were exposed to nano-alu mina (<50 n m)of 0,25,50 and 75 mg·kg -1 by nasal instillation for 1 month.Then we observed the mitochondrial ultra-structure of the nerve cells in CA3 region of hippoca mpus,and measured the mean dia meter in every group.The activities of Na +-K +-ATPase and Ca2 +-Mg2 +-ATPase were tested by the determination of the inorganic phosphorus,which was the deco mposition product of ATPase.Western blot analysis was used to detect the expression of COX-Ⅳ,Beclin1 ,LC3Ιand LC3Ⅱ.RESULTS Co mpared with 0 and 25 mg·kg -1 groups exposed to Al2 O3 nanopartilces (Al2 O3 NPs),the mitochondria of CA3 region in hip-poca mpus in 50 mg·kg -1 group beca me ede matous and swollen with sparse and broken cristae sur-rounding the nuclear,and the mean dia meter was higher(0.49 ±0.02 μm,P <0.05).But co mpared with 50 mg·kg -1 group,the mitochondria in 75 mg·kg -1 group beca me s maller with inner cristae of high density,and the mean dia meter was lower(0.36 ±0.02 μm,P<0.05).The enzy me activity of the mito-chondria in cerebral cortex decreased dose-dependently with exposure,the activities of Na +-K +-ATPase in 50 and 75 mg·kg -1 groups(6.37 ±0.22 kU·g -1 protein,5.48 ±1 .53 kU·g -1 protein)and Ca2 +-Mg2 +-ATPase in 50 and 75 mg·kg -1 groups (3.21 ±0.99 kU·g -1 protein,3.28 ±0.15 kU·g -1 protein)were lower than the 0 mg·kg -1 group(P<0.05).Meanwhile,the Ca2 +-Mg2 +-ATPase in 50 and 75 mg·kg -1 groups showed lower activities in co mparison with the 25 mg·kg -1 group.The 75 mg·kg -1 group expressed higher level of the COX-Ⅳ protein 1 .35 ±0.66(P<0.05)than other groups.Both expression of Beclin1 protein and rate of LC3Ⅱ/LC3Ⅰin 75 mg·kg -1 group were more than the 0 mg·kg -1 group. CONCLUSION The mitochondrial dysfunction may be the potential neurotoxicity of nano-alu mina,and the da maged mitochondria were cleared by autophagy.