不同剂量紫外线照射对血液抗氧化作用的影响

EffectofUV-CIrradiationontheAbilityofAntioxidationinBlood

实验用不同剂量短波紫外线（ＵＶ－Ｃ）照射家兔离体血液，采用化学发光法（ＣＬ）和分光光度法分别测定血浆超氧化物歧化酶（ＳＯＤ）活力和丙二醛（ＭＤＡ）含量。未照射血液血浆ＳＤＯ活力、ＭＤＡ含量分别为９４６．６７±５７．６５Ｕ／ｍｌ、１７．７６±３．３９ｎｍｏｌ／ｍｌ。小剂量（１５秒）照射后ＳＯＤ活力显著高于未照射血液（Ｐ＜０．０１），剂量增加后（３０秒）ＳＯＤ活力下降并接近未照射水平，照射１分钟后活力明显下降（Ｐ＜０．０５），并随短波ＵＶ－Ｃ剂量（３、６分钟）增大下降增多（Ｐ＜０．００１）。较小剂量ＵＶ－Ｃ（１５秒、３０秒、１分钟）照射后ＭＤＡ含量无明显变化，ＵＶ－Ｃ照射３分钟时ＭＤＡ含量开始出现明显升高（Ｐ＜０．０５），并随剂量加大（６分钟）进一步增高（Ｐ＜０．００１）。结果提示小剂量ＵＶ－Ｃ照射能够增强机体抗氧化能力，大剂量照射则使机体抗氧化能力下降，氧化损伤作用增强；并且说明ＵＶ－Ｃ照射所致机体脂质过氧化损伤与抗氧化能力下降，自由基生成增多。

TheisolatedbloodofrabbitswereirradiatedbydiferentdosesofUV-C.Superoxidedismu-tase(SOD)activityandmalondialdehyde(MDA)contentofbloodweredetermined.Incontrolgroup,SODactivityandMDAcontentwere946.67±57.65U/mland17.76±3.39nmol/ml.AftersmalerdoseofUV-Cirradiation(15秒),SODactivitywasremarkablyhigherthancontrol(P<0.01),IncreasingUV-Cdose(30秒),SODactivitywasdecreasedapproachingthelevelofcontrolgroup,After1minUV-Cirradi-ation,SODactivitywaslowerthancontroc(P<0.05),SODactivitywerefurtherdecreased(P<0.001)af-terlargerdosesofUV-Cirradiation(3and6min).MDAcontentshadnochangeaftersmalerdosesofUV-Cirradiation(15、30、1min);MDAcontentswereremarkablyhigherthatcontrolgroup(P<0.05、P<0.001),afterlargerdosesofUV-Cirradiation(3、6min).Theresultsshowedthattheabilityofagainstox-idativeinjuryinorganismwasenhancedbyUV-Cirradiationofsmalerdose,butlargerdoseofUV-Ccouldweakentheabilityandincreasetheoxidativeinjury.Italsoshowedthantheoxidativeinjutyhadrela-tiontothedecreaseofantioxidativeability,theincreaseoffreeradicalsformationandthescavengingoffreeradicalsinsufciently.