背景 亚硒酸钠诱导的白内障与年龄相关性白内障的形成机制具有一定的相似性,即氧化损伤,N-乙酰半胱氨酸(NAC)是一种有效的抗氧化剂,但其对白内障的预防和治疗作用研究尚少. 目的 观察NAC对亚硒酸钠诱导大鼠白内障的预防和治疗作用,为白内障的药物防治提供实验依据.方法 实验分为预防部分和治疗部分.选取SD大鼠60只,随机数字表法分为正常对照组1、正常对照组2、硒性白内障组、NAC白内障预防组、硒性白内障生理盐水组及NAC白内障治疗组,每组10只大鼠.采用3.46 mg/kg亚硒酸钠颈部皮下注射法制作硒性白内障模型,隔日1次,共3次.预防实验时在首次注射亚硒酸钠前30 min大鼠腹腔内注射2 mmol/L NAC,每日1次,共6次；治疗实验时,硒性白内障大鼠造模后1d腹腔内注射2 mmol/LNAC,每日1次,共1个月；硒性白内障生理盐水组以同样方法注射生理盐水.每周各组大鼠在裂隙灯下观察晶状体混浊程度并参考LOCSⅢ标准进行分级.各实验组大鼠最后一次注药后制备晶状体组织切片,光学显微镜下观察晶状体上皮细胞( LECs)的组织病理学改变,扫描电子显微镜下观察晶状体上皮超微结构的改变.采用免疫组织化学法观察亚硒酸钠对晶状体中caspase-3的影响；对各组大鼠晶状体组织中超氧化物歧化酶(SOD)、丙二醛(MDA)含量的变化进行生化测定.结果 实验后7d正常大鼠晶状体透明.硒性白内障组Ⅴ级晶状体混浊者有11只眼,NAC白内障预防组仅有Ⅱ级混浊8只眼和Ⅰ级混浊2只眼,差异有统计学意义(x2=40.000,P＜0.05).实验后30d,硒性白内障生理盐水组和NAC白内障治疗组Ⅳ～Ⅴ级晶状体混浊均为20只眼,差异无统计学意义(x2=0.153,P＞0.05).常规组织病理学检查表明,正常对照组LECs及晶状体纤维结构正常,硒性白内障组、硒性白内障生理盐水组和NAC白内障治疗组LECs与前囊部分分离,排列疏松紊乱,细胞膜破裂,细胞核呈椭圆形或长条形,晶状体纤维断裂,NAC白内障预防组晶状体结构破坏程度较轻.扫描电子显微镜下可见硒性白内障组、硒性白内障生理盐水组和NAC白内障治疗组晶状体前囊分层,外膜脱离,深层可见“变性球样小体”,纤维紊乱破碎,形成无结构的“水泥样”外观.硒性白内障组caspase-3和SOD的表达明显低于正常对照组,MDA的表达高于正常对照组,差异均有统计学意义(P＜0.05),而NAC白内障预防组caspase-3和SOD的表达明显高于硒性白内障组,差异均有统计学意义(P＜0.05).硒性白内障生理盐水组与NAC白内障治疗组caspase-3、SOD和MDA表达均明显低于正常对照组2,差异均有统计学意义(P＜0.05),而硒性白内障生理盐水组与NAC白内障治疗组比较,caspase-3、SOD和MDA表达的差异均无统计学意义(P＞0.05).结论 NAC可以提高晶状体组织中SOD的活性,减少MDA生成,降低caspase-3的活性,从而减轻晶状体的氧化损伤,对早期白内障的发生、发展有一定的延缓和预防作用,但对于已经形成的白内障无明显治疗作用.
揹景 亞硒痠鈉誘導的白內障與年齡相關性白內障的形成機製具有一定的相似性,即氧化損傷,N-乙酰半胱氨痠(NAC)是一種有效的抗氧化劑,但其對白內障的預防和治療作用研究尚少. 目的 觀察NAC對亞硒痠鈉誘導大鼠白內障的預防和治療作用,為白內障的藥物防治提供實驗依據.方法 實驗分為預防部分和治療部分.選取SD大鼠60隻,隨機數字錶法分為正常對照組1、正常對照組2、硒性白內障組、NAC白內障預防組、硒性白內障生理鹽水組及NAC白內障治療組,每組10隻大鼠.採用3.46 mg/kg亞硒痠鈉頸部皮下註射法製作硒性白內障模型,隔日1次,共3次.預防實驗時在首次註射亞硒痠鈉前30 min大鼠腹腔內註射2 mmol/L NAC,每日1次,共6次；治療實驗時,硒性白內障大鼠造模後1d腹腔內註射2 mmol/LNAC,每日1次,共1箇月；硒性白內障生理鹽水組以同樣方法註射生理鹽水.每週各組大鼠在裂隙燈下觀察晶狀體混濁程度併參攷LOCSⅢ標準進行分級.各實驗組大鼠最後一次註藥後製備晶狀體組織切片,光學顯微鏡下觀察晶狀體上皮細胞( LECs)的組織病理學改變,掃描電子顯微鏡下觀察晶狀體上皮超微結構的改變.採用免疫組織化學法觀察亞硒痠鈉對晶狀體中caspase-3的影響；對各組大鼠晶狀體組織中超氧化物歧化酶(SOD)、丙二醛(MDA)含量的變化進行生化測定.結果 實驗後7d正常大鼠晶狀體透明.硒性白內障組Ⅴ級晶狀體混濁者有11隻眼,NAC白內障預防組僅有Ⅱ級混濁8隻眼和Ⅰ級混濁2隻眼,差異有統計學意義(x2=40.000,P＜0.05).實驗後30d,硒性白內障生理鹽水組和NAC白內障治療組Ⅳ～Ⅴ級晶狀體混濁均為20隻眼,差異無統計學意義(x2=0.153,P＞0.05).常規組織病理學檢查錶明,正常對照組LECs及晶狀體纖維結構正常,硒性白內障組、硒性白內障生理鹽水組和NAC白內障治療組LECs與前囊部分分離,排列疏鬆紊亂,細胞膜破裂,細胞覈呈橢圓形或長條形,晶狀體纖維斷裂,NAC白內障預防組晶狀體結構破壞程度較輕.掃描電子顯微鏡下可見硒性白內障組、硒性白內障生理鹽水組和NAC白內障治療組晶狀體前囊分層,外膜脫離,深層可見“變性毬樣小體”,纖維紊亂破碎,形成無結構的“水泥樣”外觀.硒性白內障組caspase-3和SOD的錶達明顯低于正常對照組,MDA的錶達高于正常對照組,差異均有統計學意義(P＜0.05),而NAC白內障預防組caspase-3和SOD的錶達明顯高于硒性白內障組,差異均有統計學意義(P＜0.05).硒性白內障生理鹽水組與NAC白內障治療組caspase-3、SOD和MDA錶達均明顯低于正常對照組2,差異均有統計學意義(P＜0.05),而硒性白內障生理鹽水組與NAC白內障治療組比較,caspase-3、SOD和MDA錶達的差異均無統計學意義(P＞0.05).結論 NAC可以提高晶狀體組織中SOD的活性,減少MDA生成,降低caspase-3的活性,從而減輕晶狀體的氧化損傷,對早期白內障的髮生、髮展有一定的延緩和預防作用,但對于已經形成的白內障無明顯治療作用.
배경 아서산납유도적백내장여년령상관성백내장적형성궤제구유일정적상사성,즉양화손상,N-을선반광안산(NAC)시일충유효적항양화제,단기대백내장적예방화치료작용연구상소. 목적 관찰NAC대아서산납유도대서백내장적예방화치료작용,위백내장적약물방치제공실험의거.방법 실험분위예방부분화치료부분.선취SD대서60지,수궤수자표법분위정상대조조1、정상대조조2、서성백내장조、NAC백내장예방조、서성백내장생리염수조급NAC백내장치료조,매조10지대서.채용3.46 mg/kg아서산납경부피하주사법제작서성백내장모형,격일1차,공3차.예방실험시재수차주사아서산납전30 min대서복강내주사2 mmol/L NAC,매일1차,공6차；치료실험시,서성백내장대서조모후1d복강내주사2 mmol/LNAC,매일1차,공1개월；서성백내장생리염수조이동양방법주사생리염수.매주각조대서재렬극등하관찰정상체혼탁정도병삼고LOCSⅢ표준진행분급.각실험조대서최후일차주약후제비정상체조직절편,광학현미경하관찰정상체상피세포( LECs)적조직병이학개변,소묘전자현미경하관찰정상체상피초미결구적개변.채용면역조직화학법관찰아서산납대정상체중caspase-3적영향；대각조대서정상체조직중초양화물기화매(SOD)、병이철(MDA)함량적변화진행생화측정.결과 실험후7d정상대서정상체투명.서성백내장조Ⅴ급정상체혼탁자유11지안,NAC백내장예방조부유Ⅱ급혼탁8지안화Ⅰ급혼탁2지안,차이유통계학의의(x2=40.000,P＜0.05).실험후30d,서성백내장생리염수조화NAC백내장치료조Ⅳ～Ⅴ급정상체혼탁균위20지안,차이무통계학의의(x2=0.153,P＞0.05).상규조직병이학검사표명,정상대조조LECs급정상체섬유결구정상,서성백내장조、서성백내장생리염수조화NAC백내장치료조LECs여전낭부분분리,배렬소송문란,세포막파렬,세포핵정타원형혹장조형,정상체섬유단렬,NAC백내장예방조정상체결구파배정도교경.소묘전자현미경하가견서성백내장조、서성백내장생리염수조화NAC백내장치료조정상체전낭분층,외막탈리,심층가견“변성구양소체”,섬유문란파쇄,형성무결구적“수니양”외관.서성백내장조caspase-3화SOD적표체명현저우정상대조조,MDA적표체고우정상대조조,차이균유통계학의의(P＜0.05),이NAC백내장예방조caspase-3화SOD적표체명현고우서성백내장조,차이균유통계학의의(P＜0.05).서성백내장생리염수조여NAC백내장치료조caspase-3、SOD화MDA표체균명현저우정상대조조2,차이균유통계학의의(P＜0.05),이서성백내장생리염수조여NAC백내장치료조비교,caspase-3、SOD화MDA표체적차이균무통계학의의(P＞0.05).결론 NAC가이제고정상체조직중SOD적활성,감소MDA생성,강저caspase-3적활성,종이감경정상체적양화손상,대조기백내장적발생、발전유일정적연완화예방작용,단대우이경형성적백내장무명현치료작용.
Background The mechanism of both selenite-induced cataract and age-related cataract is oxidative damage.N-acetylcysteine (NAC) is one of the effective antioxidants,but the literature is little about the preventive and treating effects of NAC on cataract. Objective This study attempted to investigate the preventive and therapeutical effects of NAC on the selenite-induced cataract,and to discuss the possible mechanism. Methods Sixty 10-day-old clean SD rats were randomly divided into normal control group-1,normal control group-2,selenite-induced cataract group,NAC preventive group,NAC+normal saline group and NAC treatment group.Selenite cataract models were induced by subcutaneous injection of 3.46 mg/kg sodium selenite once daily for three days.The rats of NAC preventive group received the intraperitoneal injection of 2 mmol/L NAC 30 minutes before the injection of sodium selenite once daily for 6 days.In NAC treating group,2 mmol/L NAC was intraperitoneally injected 1 day after the injection of sodium selenite for 30 days,and the normal saline solution was injected at the same method in the NAC+normal saline group.Lens opacification was graded according to LOCS Ⅲ criteria.Histopathological change of lens epithelium was examined under a light microscope after hemotoxylin and eosin staining,and the ultrastructure was observed under the scanning electron microscope.The expression of caspase-3 in lens was assayed using immunochemistry.The levels of superoxide dismutase ( SOD ),malonaldehyde ( MDA ) in rat lens were detected respectively in corresponding time points.The use of the experimental animals complied with the Regulation for the Administration of Affairs Concerning Experimental Animals by State Science and Technology Committee. Results In 7 days after experiment,lenses were completely clear in the normal control group.Lens opacification of Ⅴ grade was found in 11 eyes in selenite cataract model group,but no lens opacification of Ⅴ grade was seen in NAC preventive group,showing a significant difference(x2 =40.000,P＜0.05 ).In 30 days after experiment,Ⅳ- Ⅴ grades of cataracts were found in 20 eyes both in NAC + normal saline group and NAC treating group (x2=0.153,P＞ 0.05 ).Histopathological examination showed that lens structure was normal,and the separation between LECs and anterior capsule,the rupture of cellular membrane,deformation of cellular nuclei and the feature of lens fiber were seen in selenite cataract group,but the damage of lens was mild in the NAC preventive group.Ultrastructure of lens was obviously abnormal in selenite cataract group,NAC+normal saline group and NAC treating group.Expressions of caspase-3 and SOD in lens were significantly lower,but that of MDA was significantly higher in the selenite cataract group than the normal control group (P＜0.05) ;while those of the NAC preventive group were significantly different from selenite cataract group(P＜0.05).No significant difference was found in the expressions of caspase-3 and the levels of SOD and MDA between NAC+normal saline group and NAC treating group (P＞0.05 ). Conclusions Selenite can induce the apoptosis of LECs.NAC can evidently postpone formation of selenite cataract by increasing the activity of SOD,decreasing the level of MDA and the expression of caspase-3.However,NAC could not reverse selenite-induced lens damage.
