自噬及凋亡因子在慢性氟中毒大鼠肝脏中表达

目的 探讨自噬相关因子LC3A、Beclin-1及凋亡因子Bcl-2、Bax在慢性氟中毒大鼠肝脏中的表达意义。方法 将36只健康SD大鼠按体重随机分为对照组、低氟组、高氟组，分别用含氟量<1 mg/L的自来水和含氟5、50 mg/L的含氟水饲养6个月，观察氟斑牙形成情况；测定尿氟、骨氟含量以及大鼠肝功能；苏木素-伊红染色观察肝脏病理形态学改变；免疫组织化学法检测大鼠肝组织中微管相关蛋白轻链3A （LC3A）、哺乳动物ATG6同源蛋白（Beclin-1）及B细胞淋巴瘤/白血病-2蛋白（Bcl-2）、B细胞淋巴瘤/白细胞基因伴随蛋白x （Bax）的蛋白表达水平。结果 与对照组比较，低、高氟组大鼠尿氟含量分别为[（2.18±0.14）、（2.40±0.19） mg/L]、骨氟含量分别为[（237.42±18.48）、（248.00±14.72） mg/kg]均明显升高（P<0.05）；染氟组大鼠肝脏肝细胞索排列紊乱，肝细胞肿大，部分肝细胞胞质透亮，呈空泡样改变；与对照组比较，染氟组大鼠血清中谷丙转氨酶活性及谷草转氨酶活性明显升高（P<0.05）；低、高氟组大鼠肝脏LC3A[（35.35±2.71）、（44.10±6.72）]、Beclin-1[（57.56±12.1）、（74.76±18.67）]及Bax[（51.1±9.23）、（62.32±10.3）]蛋白表达明显高于对照组，Bcl-2蛋白表达分别为[（55.18±8.36）、（39.05±6.91）]明显低于对照组（P<0.05）。结论 过量氟可激活大鼠肝组织中自噬和凋亡因子，自噬和凋亡可能共同参与慢性氟中毒所致肝脏损伤的发病过程。

Expressions of LC3A,Beclin-1,Bcl-2 and Bax in liver of fluorosis rat

Objective To explore expressions of microtubule associated protein light chain 3A (LC3A),a mammalian homolog of yeast Atg6/vps30 (Beclin-1),B-cell leukemia/lymphoma 2 (Bcl-2),and Bcl-2 assaciated X protein (Bax) in livers of rats with fluorosis.Methods Thirty-six healthy Sprague-Dawley (SD) rats were randomly divided into three groups:a control group (supplied with drinking water containing sodium fluoride[NaF] of <1 mg/L),low fluorine group (5 mg/L NaF in drinking water),and high fluorine group (50 mg/L NaF in drinking water).The incidence of detal fluorosis in all the groups was determined after the 6-month treatment.The fluorine content in the urine and bone of the rats was measured with fluorine-ion method.The rats' liver function was tested with automatic blood chemical analyzer.The pathomorphologic changes in the livers of the rats were observed with light microscope.The protein expressions of LC3A,Beclin-1,Bcl-2,and Bax were detected with immunohistochemistry (IHC) method.Results Significantly increased urinary and bone fluoride contents were observed in the rats of low fluorine group (2.18±0.14 mg/L,237.42±18.48 mg/kg) and high fluorine group (2.40±0.19 mg/L,248.00±14.72 mg/kg) compared to those in the rats of control group (1.92±0.12 mg/L,185.57±13.27 mg/kg) (P<0.05 for all).In the rats of low and high fluorine groups,the hepatocytes were disorganized and swollen with cytoplasmic clearing.The activity of serum alanine transaminase (ALT) and aspartate aminotransferase (AST) significantly increased in the rats of low fluorine group (52.84±2.24 U/L,74.67±6.27U/L) and high fluorine group (135.52±13.52 U/L,154.46±12.66 U/L),both higher than those of the control rats (38.75±4.15 U/L,121.74±10.43 U/L)(P<0.05 for all).Significantly high expressed LC3A (35.35±2.71,44.10±6.72),Beclin-1 (57.56±12.1,74.76±18.67),and Bax (51.1±9.23,62.32±10.3),but low expressed Bcl-2 (55.18±8.36,39.05±6.91) were observed in the rats of low and high fluorine groups compared to those of the control rats (27.55±2.32,40.23±6.96,40.00±8.02,79.21±11.00) (P<0.05 for all).Conclusion Excessive fluorine can promote expressions of proteins related to autophagy and apoptosis of hepatocytes,which may play important roles in the pathogenesis of liver damage induced by chronic fluorosis.