趙金坤,梁宏偉,鄒桂偉,王煥嶺,李 忠
(1 華中農(nóng)業(yè)大學(xué) 水產(chǎn)學(xué)院,湖北 武漢 430070;2 中國水產(chǎn)科學(xué)研究院 長江水產(chǎn)研究所,湖北 武漢 430223)
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低氧脅迫對鰱肝和腦細(xì)胞凋亡的影響
趙金坤1,梁宏偉2,鄒桂偉2,王煥嶺1,李忠2
(1 華中農(nóng)業(yè)大學(xué) 水產(chǎn)學(xué)院,湖北 武漢 430070;2 中國水產(chǎn)科學(xué)研究院 長江水產(chǎn)研究所,湖北 武漢 430223)
[摘要]【目的】 通過磷脂結(jié)合蛋白V/碘化丙啶(Annexin V/PI)流式細(xì)胞分析法和原位末端脫氧核苷酸轉(zhuǎn)移酶標(biāo)記(TUNEL)法檢測低氧脅迫下鰱肝、腦細(xì)胞的凋亡情況?!痉椒ā?將鰱分成對照組和低氧處理組,對照組正常飼養(yǎng),低氧處理組用保鮮膜將水箱上口封住進(jìn)行低氧處理,分別在鰱浮頭期以及死亡期取其肝、腦組織,同時取對照組鰱肝、腦組織,采用Annexin V/PI流式細(xì)胞分析法和TUNEL法檢測其細(xì)胞凋亡情況。【結(jié)果】 Annexin V/PI流式細(xì)胞儀分析結(jié)果表明,在鰱肝臟中細(xì)胞凋亡率依次是對照組8.85%、低氧處理組浮頭期22.06%、低氧處理組死亡期22.91%;腦中細(xì)胞凋亡率依次是對照組8.18%、低氧處理組浮頭期24.80%、低氧處理組死亡期24.86%。TUNEL法檢測結(jié)果顯示,肝臟中細(xì)胞凋亡率是對照組3.80%、低氧處理組浮頭期36.78%、低氧處理組死亡期37.27%;腦中細(xì)胞凋亡率依次是對照組6.74%、低氧處理組浮頭期35.04%、低氧處理組死亡期35.71%。與正常對照組比較,低氧脅迫后鰱肝、腦細(xì)胞凋亡率極顯著增大,但隨著低氧脅迫時間延長細(xì)胞凋亡率無明顯差異?!窘Y(jié)論】 低氧脅迫會極顯著促進(jìn)鰱肝和腦細(xì)胞發(fā)生凋亡,但鰱肝、腦組織中細(xì)胞凋亡率不會隨著低氧脅迫時間延長而產(chǎn)生顯著差異。
[關(guān)鍵詞]鰱;細(xì)胞凋亡;低氧脅迫;Annexin V/PI;TUNEL
細(xì)胞凋亡又稱細(xì)胞程序性死亡,是指細(xì)胞在一定的生理或病理條件下,遵循自身程序,自己結(jié)束生命的過程。細(xì)胞凋亡是一個主動、高度有序、由基因控制以及一系列酶參與的過程,在保證多細(xì)胞生物健康生存過程中扮演著關(guān)鍵的角色[1-3]。細(xì)胞凋亡概念的提出引起廣大研究者的濃厚興趣,隨著細(xì)胞凋亡研究的不斷深入,各種各樣檢測細(xì)胞凋亡的新技術(shù)和新方法相繼建立。流式細(xì)胞術(shù)(Flow cytometry,F(xiàn)CM)是近年來廣泛使用的一種先進(jìn)的細(xì)胞多參數(shù)分析儀器,具有靈敏、快速、準(zhǔn)確、并且能同時進(jìn)行多種因素分析等特點。原位末端脫氧核苷酸轉(zhuǎn)移酶標(biāo)記(TUNEL)是分子生物學(xué)與形態(tài)學(xué)相結(jié)合的細(xì)胞凋亡檢測方法,可對完整的單個凋亡細(xì)胞核或凋亡小體進(jìn)行原位染色,能準(zhǔn)確地反映細(xì)胞凋亡最典型的生物化學(xué)和形態(tài)特征[4]。
鰱(Hypophthalmichthysmolitrix)屬鯉科鰱亞科,是我國淡水養(yǎng)殖的主要魚類之一。鰱對外界刺激應(yīng)激強烈,耐低氧能力差,易泛塘,低氧脅迫會對其造成嚴(yán)重的影響。因此,研究鰱在低氧條件下的反應(yīng)機制,對其生理特性及新品種的選育具有重要的指導(dǎo)價值。本研究采用磷脂結(jié)合蛋白V/碘化丙啶(Annexin V/PI)流式細(xì)胞分析法和TUNEL法對低氧脅迫下鰱肝、腦細(xì)胞的凋亡情況進(jìn)行了檢測,現(xiàn)將結(jié)果報道如下。
1材料與方法
1.1材料
1.1.1供試動物供試鰱來自中國水產(chǎn)科學(xué)研究院長江水產(chǎn)研究所窯灣試驗場,體質(zhì)量(63±2) g/尾。
1.1.2試劑及儀器AnnexinV-FITC細(xì)胞凋亡檢測試劑盒,購自南京碧波生物科技有限公司;TUNEL細(xì)胞凋亡檢測試劑盒,購自Roche Applied Science公司;流式細(xì)胞儀,購自美國BD公司。
1.2方法
1.2.1低氧處理將鰱在循環(huán)水養(yǎng)殖系統(tǒng)中馴養(yǎng),每個水箱(38 cm×26 cm×23 cm)投放5尾健康鰱,共6箱30尾魚。1周后分為對照組和低氧處理組,每組3箱。試驗期間用溶氧儀測定各處理水中溶氧量。對照組鰱正常飼養(yǎng)(溶氧量6.85 mg/L);低氧處理組用保鮮膜將水箱上口封住,分別于鰱浮頭期(低氧處理6 h,此時溶氧量0.72 mg/L)、死亡期(低氧處理8 h,此時溶氧量0.26 mg/L)時,迅速將試驗魚取出,同時取對照魚,在超凈工作臺中解剖取組織,用于流式細(xì)胞儀檢測的樣品,每個處理采集3尾鰱的肝臟、腦組織,用含有雙抗的PBS緩沖液暫時保存;用于TUNEL法檢測的樣品,每個處理采集3尾鰱的肝臟、腦組織,用40 g/L多聚甲醛固定保存。
1.2.2單細(xì)胞懸液的制備將用PBS保存的肝臟、腦組織分別用手術(shù)剪剪成1 mm3的小組織塊,用含有雙抗的PBS緩沖液浸洗5次。將上述處理的組織用胰酶(2.5 g/L)消化30 min。然后將消化好的組織過孔徑74 μm細(xì)胞篩,收集流穿液,加入含體積分?jǐn)?shù)10%胎牛血清的1640培養(yǎng)基,200g離心3 min,棄上清液,收集底部細(xì)胞,重復(fù)3次。最后用含體積分?jǐn)?shù)10%胎牛血清的1640培養(yǎng)基懸浮細(xì)胞,即得單細(xì)胞懸液。
1.2.3細(xì)胞凋亡的Annexin V/PI流式細(xì)胞儀檢測取 1.2.2 節(jié)制備好的單細(xì)胞懸液用PBS潤洗2次,1 000 r/min離心10 min,去上清,加入體積分?jǐn)?shù)70%冷乙醇4 ℃固定30 min,離心去固定液,細(xì)胞用PBS重懸5 min,離心去上清。向細(xì)胞沉淀樣品中分別加入500 μL Binding Buffer、5 μL AnnexinV-FTIC和5 μL PI,混勻,室溫避光反應(yīng)15 min,用流式細(xì)胞儀檢測細(xì)胞凋亡率。
1.2.4細(xì)胞凋亡的TUNEL法檢測用常規(guī)方法制備鰱肝臟和腦組織的石蠟切片,依次將其放入二甲苯Ⅰ、二甲苯Ⅱ、無水乙醇Ⅰ、無水乙醇Ⅱ及體積分?jǐn)?shù)95%、90%、80%、70%的乙醇中脫蠟,然后用蒸餾水浸泡2 min。向脫蠟后的切片加蛋白酶K工作液(10~20 μg/mL),20~37 ℃反應(yīng)15~30 min,用PBS洗滌3次,每次5 min。向上處理所得切片滴加50 μLTUNEL反應(yīng)混合液,37 ℃避光孵育60 min,然后用PBS洗滌3次,每次5 min。用吸水紙擦干玻片后加50 μL converter-POD于標(biāo)本上,37 ℃避光孵育30 min,PBS洗滌4次,每次5 min。滴加50~100 μL DAB顯色液,室溫顯色0.5~5 min或者根據(jù)顯色情況延長顯色時間,最后用自來水沖洗終止顯色。顯色后的切片用Harris蘇木素復(fù)染 0.5~1 min,水洗后用體積分?jǐn)?shù)1%鹽酸酒精分化,再用PBS水洗反藍(lán),用體積分?jǐn)?shù)95%乙醇脫水5 min,再用無水乙醇脫水2次,每次約3 min;二甲苯透明2次,每次2 min,通風(fēng)櫥中風(fēng)干后中性樹膠封片。在顯微鏡下觀察切片,并采集圖像。
1.3統(tǒng)計學(xué)分析
所有數(shù)據(jù)均以“平均值±標(biāo)準(zhǔn)差”表示,采用SPASS 17.0統(tǒng)計軟件進(jìn)行分析,組間比較用t檢驗,以P<0.05為差異有統(tǒng)計學(xué)意義。
2結(jié)果與分析
2.1Annexin V/PI流式細(xì)胞分析法檢測低氧脅迫下鰱肝、腦細(xì)胞凋亡情況
結(jié)果(表1)顯示,對照組和低氧處理組浮頭期、死亡期鰱肝臟細(xì)胞凋亡率依次是8.85%,22.06%和22.91%;腦的細(xì)胞凋亡率依次是8.18%,24.80%和24.86%;與正常對照組相比,低氧處理組鰱浮頭期和死亡期肝、腦細(xì)胞凋亡率均極顯著增大(P<0.01),但低氧處理組鰱浮頭期和死亡期肝、腦細(xì)胞凋亡差異不顯著(P>0.05)。
表 1 Annexin V/PI流式細(xì)胞分析法檢測低氧脅迫下鰱肝、腦細(xì)胞的凋亡結(jié)果Table 1 Apoptosis of Hypophthalmichthys molitrix hepatocyte and brain cells under hypoxic stress detected by Annexin V/PI with flow cytometry %
注:同列數(shù)據(jù)后標(biāo)不同小寫字母表示差異顯著(P<0.05),標(biāo)不同大寫字母表示差異極顯著(P<0.01)。表2同。
Note:Different lowercase letters mean significant difference(P<0.05),different capital letters mean extremely significant difference(P<0.01).The same for Table 2.
2.2TUNEL法檢測低氧脅迫對鰱肝、腦細(xì)胞凋亡的影響
TUNEL法染色后,正常對照組的細(xì)胞經(jīng)蘇木素復(fù)染后細(xì)胞核呈藍(lán)黑色;TUNEL陽性細(xì)胞形態(tài)學(xué)上表現(xiàn)為核固縮,胞體縮小,染色質(zhì)凝聚,呈棕黃色或黃褐色顆粒,表現(xiàn)出凋亡的特征。本試驗顯微鏡觀察結(jié)果如圖1和圖2所示。
TUNEL法檢測低氧脅迫下鰱肝、腦細(xì)胞凋亡率統(tǒng)計結(jié)果如表2所示。由表2可知,對照組、低氧處理浮頭期和死亡期鰱肝臟中細(xì)胞凋亡率依次是3.80%,36.78%和37.27%,腦中細(xì)胞凋亡率依次是6.74%,35.04%和35.71%;與正常對照組相比,低氧處理組浮頭期和死亡期鰱肝、腦細(xì)胞凋亡率均極顯著增大(P<0.01);低氧處理組鰱浮頭期和死亡期肝、腦細(xì)胞凋亡差異不顯著(P>0.05)。這說明低氧脅迫會極顯著促進(jìn)鰱肝和腦細(xì)胞發(fā)生凋亡,但鰱肝、腦組織中細(xì)胞凋亡率不會隨著低氧脅迫時間延長而產(chǎn)生顯著差異。
圖 1低氧脅迫下鰱肝細(xì)胞凋亡的TUNEL法檢測結(jié)果
T.正常對照組;F.浮頭期(低氧處理6 h);D.死亡期(低氧處理8 h)
Fig.1Apoptosis ofHypophthalmichthysmolitrixhepatocyte under hypoxic stress detected with TUNEL
T.Normal control group;F.Floating stage(6 h under hypoxic stress);D.Death stage(8 h under hypoxic stress)
圖 2 低氧脅迫下鰱腦細(xì)胞凋亡的TUNEL法檢測結(jié)果 T.正常對照組;F.浮頭期(低氧處理6 h);D.死亡期(低氧處理8 h)Fig.2 Apoptosis of Hypophthalmichthys molitrix brain cells under hypoxic stress detected with TUNEL T.Normal control group;F.Floating stage(6 h under hypoxic stress);D.Death stage(8 h under hypoxic stress)
表 2 TUNEL法檢測低氧脅迫下鰱肝、腦細(xì)胞的凋亡結(jié)果Table 2 Apoptosis of Hypophthalmichthys molitrix hepatocyte and brain cellsunder hypoxic stress detected with TUNEL %
3討論
水體中溶解氧含量降低對魚類可造成多方面的影響,魚類在行為上會出現(xiàn)臨界游泳速度降低、呼吸攝氧能力下降等[5],從而影響到魚類的洄游、覓食等生理活動[6]。而魚類的生理生化過程更是涉及到血管形成與氧氣運輸、細(xì)胞凋亡、細(xì)胞增殖、基因表達(dá)以及細(xì)胞結(jié)構(gòu)等[7]。大量動物試驗研究發(fā)現(xiàn),低氧可通過誘導(dǎo)Rb的磷酸化和p27的表達(dá)來降低cyclin-CDK復(fù)合物的活性,引起細(xì)胞周期阻滯,促進(jìn)細(xì)胞凋亡,使DNA的合成和細(xì)胞數(shù)目顯著降低[8-10]。缺氧可引起肝細(xì)胞線粒體、生物膜損傷以及肝細(xì)胞氧化磷酸化,導(dǎo)致產(chǎn)能減少;缺氧還可引起鈣超載觸發(fā)細(xì)胞凋亡。線粒體功能受損還會引起肝臟氧自由基增多導(dǎo)致蛋白質(zhì)、脂肪、DNA氧化損傷,從而導(dǎo)致細(xì)胞凋亡[11]。黎一鳴等[12]在肝動脈缺血對肝細(xì)胞凋亡影響的研究中發(fā)現(xiàn),氧自由基在肝動脈缺血誘發(fā)的肝組織細(xì)胞凋亡中發(fā)揮了重要的作用。氧自由基可促進(jìn)組織中活性氧的產(chǎn)生,從而誘發(fā)細(xì)胞凋亡。本試驗對低氧脅迫后鰱肝臟組織的細(xì)胞凋亡情況進(jìn)行了檢測,結(jié)果發(fā)現(xiàn),低氧處理至鰱浮頭再到死亡,肝細(xì)胞凋亡率較正常對照組極顯著升高(P<0.01),但低氧處理組浮頭期和死亡期肝細(xì)胞凋亡率差異不顯著,說明低氧可誘導(dǎo)鰱肝細(xì)胞的凋亡,但隨著低氧處理時間的延長,肝臟組織凋亡細(xì)胞數(shù)目無顯著差異。
中樞神經(jīng)系統(tǒng)(CNS)對缺氧最為敏感,而且對缺氧的耐受性較差,缺氧可誘導(dǎo)中樞神經(jīng)系統(tǒng)慢性或急性損傷。在腦缺氧損傷中,不僅存在細(xì)胞壞死發(fā)生,還存在細(xì)胞凋亡現(xiàn)象,細(xì)胞凋亡是腦缺氧后遲發(fā)性神經(jīng)元死亡的重要表現(xiàn)形式[13]。一些動物試驗表明,腦缺氧缺血損傷后在細(xì)胞死亡過程中存在2個不同的階段,第一階段是在缺氧缺血損傷期間細(xì)胞主要以壞死形式發(fā)生,在這一階段細(xì)胞死亡涉及神經(jīng)膠質(zhì)和神經(jīng)元細(xì)胞;第二階段是延遲發(fā)生,細(xì)胞以凋亡為主,在這一階段細(xì)胞選擇性涉及神經(jīng)元死亡,即遲發(fā)性神經(jīng)元死亡[14-15]。本試驗對低氧脅迫后鰱腦組織的細(xì)胞凋亡情況進(jìn)行了檢測,結(jié)果發(fā)現(xiàn),低氧處理至鰱浮頭再到死亡,腦細(xì)胞凋亡率較正常對照組極顯著升高(P<0.01),但浮頭期和死亡期腦細(xì)胞凋亡率差異不顯著,說明低氧可誘導(dǎo)鰱腦細(xì)胞的凋亡,但隨著低氧處理時間的延長,腦組織凋亡細(xì)胞數(shù)目無顯著差異。
本試驗低氧處理浮頭期和死亡期鰱肝、腦細(xì)胞凋亡率無顯著差異的原因可能是,低氧誘導(dǎo)細(xì)胞凋亡存在一個臨界值,當(dāng)氧濃度下降到這一臨界值時,細(xì)胞凋亡率的增加不明顯[16]。
[參考文獻(xiàn)]
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DOI:網(wǎng)絡(luò)出版時間:2016-06-0816:2110.13207/j.cnki.jnwafu.2016.07.005
[收稿日期]2014-11-30
[基金項目]國家自然科學(xué)基金項目(31101894);“十二五”國家科技支撐計劃項目(2012BAD26B02);現(xiàn)代農(nóng)業(yè)產(chǎn)業(yè)技術(shù)體系建設(shè)專項(nycytx-49-01)
[作者簡介]趙金坤(1989-),男(滿族),遼寧本溪人,在讀碩士,主要從事水產(chǎn)動物遺傳育種研究。E-mail:zjk1989akun@yeah.net [通信作者]李忠(1976-),男,山東濟南人,副研究員,博士,主要從事魚類遺傳育種研究。E-mail:Lizhong@yfi.ac.cn
[中圖分類號]S852
[文獻(xiàn)標(biāo)志碼]A
[文章編號]1671-9387(2016)07-0034-05
Influence of hypoxic stress on apoptosis of hepatocyte and brain cells of silver carp(Hypophthalmichthysmolitrix)
ZHAO Jinkun1,LIANG Hongwei2,ZOU Guiwei2,WANG Huanling1,LI Zhong2
(1CollegeofFisheries,HuazhongAgriculturalUniversity,Wuhan,Hubei430070,China;2YangtzeRiverFisheriesResearchInstitute,ChineseAcademyofFisherySciences,Wuhan,Hubei430223,China)
Abstract:【Objective】 The apoptosis of hepatocyte and brain cells of silver carp(Hypophthalmichthys molitrix) under hypoxic stress was investigated by Annexin V/PI with flow cytometry and TUNEL.【Method】 Silver carp individuals were divided intonormal control group and hypoxic stress treatment group.The normal control group was normally bred while the hypoxic stress treatment group was treated with hypoxia in water tank,which was sealed with plastic wrap.Samples of liver and brain of silver carp were collected from normal and treatment groups at floating and death stages to analyze the apoptosis of hepatocyte and brain cells using Annexin V/PI with flow cytometry and TUNEL.【Result】 Rates of hepatocyte apoptosis of silver carp were 8.85% for control group,22.06% at floating stage and 22.91%at death stage.Rates of brain cells apoptosis were 8.18%,24.80% and 24.86% accordingly.TUNEL measurement showed that rates of hepatocyte apoptosis were 3.80%,36.78% and 37.27% for control,floating state and death stage,while those of brain cells apoptosis were 6.74%,35.04% and 35.71%.Compared with the control group,the apoptosis of hepatocyte and brain cells of silver carp was significantly increased under hypoxic stress.However,with the increase of hypoxia time,the number of apoptosis cells did not change significantly.【Conclusion】 Hypoxia stress significantly promoted the apoptosis of hepatocyte and brain cells of silver carp and the rates were not significantly changed by hypoxia time.
Key words:silver carp;cells apoptosis;hypoxic stress;Annexin V/PI;TUNEL
網(wǎng)絡(luò)出版地址:http://www.cnki.net/kcms/detail/61.1390.S.20160608.1621.010.html