卞林翠,王敏,賀利敏,徐金勇,李光武
(安徽醫(yī)科大學(xué)神經(jīng)生物學(xué)研究所,合肥230032)
玫瑰花蕾萃取物對(duì)嗅球毀損大鼠梨形皮質(zhì)神經(jīng)元損傷修復(fù)的影響及機(jī)制
卞林翠,王敏,賀利敏,徐金勇,李光武
(安徽醫(yī)科大學(xué)神經(jīng)生物學(xué)研究所,合肥230032)
目的 觀察玫瑰花蕾萃取物對(duì)嗅球毀損大鼠梨形皮質(zhì)神經(jīng)元損傷修復(fù)的影響,探討其作用機(jī)制。方法 將60只成年健康雄性SD大鼠隨機(jī)分為對(duì)照組(10只)、模型組(40只)及玫瑰花蕾組(10只)。對(duì)照組不做任何處理。模型組及玫瑰花蕾組采用探針破壞嗅球。嗅球毀損后1天,玫瑰花蕾組行玫瑰花蕾萃取物吸嗅,每次持續(xù)吸嗅1 h、2次/d,連續(xù)14天。分別取對(duì)照組、模型組嗅球毀損后24 h、72 h、7 d、14 d(每個(gè)時(shí)間10只)及玫瑰花蕾組吸嗅14天后腦組織,常規(guī)切片,采用尼氏染色法檢測各組梨形皮質(zhì)神經(jīng)元損傷修復(fù)情況,采用免疫組化法檢測梨形皮質(zhì)谷氨酸(Glu)、γ-氨基丁酸(GABA)表達(dá)。結(jié)果 對(duì)照組梨形皮質(zhì)神經(jīng)元尼式小體灰度值為87.32±3.14,模型組毀損24 h、72 h、7 d、14 d時(shí)灰度值分別為101.76±4.52、110.76±2.78、98.35±2.69、94.26±3.01,玫瑰花蕾組為88.47±4.33;模型組毀損72 h時(shí)尼式小體灰度值大于對(duì)照組和玫瑰花蕾組(P均<0.05)。與對(duì)照組比較,模型組毀損72 h、7 d時(shí)梨形皮質(zhì)Glu表達(dá)減少、GABA表達(dá)增加;與模型組毀損72 h、7 d 比較,玫瑰花蕾組Glu表達(dá)增加、GABA表達(dá)減少;兩組比較P均<0.05。結(jié)論 玫瑰花蕾萃取物吸嗅對(duì)嗅球毀損大鼠梨形皮質(zhì)神經(jīng)元損傷修復(fù)具有促進(jìn)作用,抑制Glu釋放、促進(jìn)GABA釋放可能是其作用機(jī)制。
玫瑰花蕾萃取物;嗅球毀損;梨形皮質(zhì);神經(jīng)遞質(zhì);嗅覺通路;神經(jīng)元再生
梨形皮質(zhì)是哺乳動(dòng)物嗅覺皮質(zhì)中最大的一個(gè)區(qū)域,可以接收來自嗅球和其他二級(jí)嗅覺皮層的傳入纖維[1]。從嗅球發(fā)出的僧帽細(xì)胞和叢毛細(xì)胞通過外側(cè)嗅束投射至梨形皮質(zhì),形成樹狀分支。研究發(fā)現(xiàn),神經(jīng)遞質(zhì)參與嗅覺的形成與傳導(dǎo),其中谷氨酸(Glu)和γ-氨基丁酸(GABA)在嗅覺系統(tǒng)中發(fā)揮重要作用[2,3]。當(dāng)嗅球毀損后嗅覺信息傳導(dǎo)受到阻滯,嗅覺神經(jīng)發(fā)生潰變,神經(jīng)回路發(fā)生改變。玫瑰花蕾萃取物具有提神醒腦、活血化瘀、通經(jīng)活絡(luò)、促進(jìn)血液循環(huán)等功效。2013年10月~2015年11月,本研究觀察了玫瑰花蕾萃取物吸嗅對(duì)嗅球毀損大鼠梨形皮質(zhì)神經(jīng)元損傷修復(fù)的影響,現(xiàn)分析結(jié)果并探討其機(jī)制。
1.1 材料 成年健康雄性SD大鼠60只,體質(zhì)量220~250 g,由安徽醫(yī)科大學(xué)動(dòng)物中心提供,動(dòng)物合格證號(hào):SCXK(皖)2011-002。腦立體定位儀(型號(hào)NARISHIGE,TYPE:SN-2,NO:8208,日本),生物組織石蠟包埋機(jī)(中國湖北),切片機(jī)(Leica石蠟切片機(jī),型號(hào)RM2135,德國),顯微鏡(Nikon80i型,日本)等。玫瑰花蕾萃取物(安徽澳德瑞生物科技有限公司),濃縮型DAB試劑盒(北京中杉金橋生物技術(shù)有限公司),兔抗Glu抗體試劑盒、兔抗GABA抗體試劑盒(北京博奧森生物技術(shù)有限公司)。
1.2 模型制作及處理 將60只SD大鼠隨機(jī)分為三組,分別為對(duì)照組10只、模型組40只及嗅球毀損后玫瑰花蕾萃取物吸嗅組(玫瑰花蕾組)10只。對(duì)照組不做任何處理。模型組及玫瑰花蕾組建立嗅球毀損模型:大鼠經(jīng)10%水合氯醛腹腔注射麻醉(3 mL/kg),將頭部固定于腦立體定位儀,于鼻額縫部位沿頭顱正中切開頭部皮膚、皮下軟組織及骨膜,暴露顱骨、前囟,參考《The Rat Brain》(第三版,George Paxinos, Charles Watson)[4]定位嗅球,用電鉆在對(duì)應(yīng)嗅球的顱骨處鉆一孔(直徑25 mm左右),探針攪動(dòng)破壞嗅球,并將殘余組織吸出,創(chuàng)口用可吸收性明膠海綿填塞止血,縫合創(chuàng)口。嗅球毀損后1天,玫瑰花蕾組行玫瑰花蕾萃取物吸嗅:將玫瑰花蕾萃取物放入吸嗅桶底部,上面放置帶有很多小孔的薄塑料隔板,讓玫瑰花蕾萃取物充分揮發(fā)彌漫在整個(gè)吸嗅桶中,再將大鼠放在隔板上。每次持續(xù)吸嗅1 h,2次/d,連續(xù)14天。
分別取對(duì)照組、玫瑰花蕾組(吸嗅14天)所有大鼠,模型組于模型制作24 h、72 h、7 d、14 d分別取大鼠10只,用10%水合氯醛腹腔注射麻醉(3 mL/kg),打開胸腔暴露心臟,自左心室插管至升主動(dòng)脈,剪開右側(cè)心耳,快速滴注生理鹽水至右心房流出無色液體為止。迅速開顱取出整個(gè)大腦,放入4%多聚甲醛溶液中持續(xù)固定48 h。將固定好的腦組織分別進(jìn)行脫水、透明、浸蠟、包埋。對(duì)照大鼠腦立體定位圖譜[4],用切片機(jī)進(jìn)行連續(xù)冠狀切片,片厚5 μm,每3片取1片,90 ℃烤片15 min,收儲(chǔ)備用。
1.3 相關(guān)指標(biāo)觀察
1.3.1 梨形皮質(zhì)神經(jīng)元損傷修復(fù)情況 采用尼氏染色法。取各組腦組織切片脫蠟至水,將切片置于5 g/L硫瑾水溶液,然后置入37 ℃溫箱20 min,取出切片冷卻,蒸餾水洗滌,乙醇分色,伊紅乙醇溶液染色,脫水,透明,封片,拍片。顯微鏡下觀察各組梨形皮質(zhì)尼式小體的形態(tài)及數(shù)量,采用Image-Pro-Plus6.0彩色圖像分析系統(tǒng)分析各組尼式小體灰度值。
1.3.2 梨形皮質(zhì)Glu、GABA表達(dá) 采用免疫組化法。取各組腦組織切片脫蠟至水,抗原修復(fù),加入一抗(兔抗Glu抗體/兔抗GABA抗體,稀釋濃度均為1∶150)4 ℃過夜,滴加PV-6004于37 ℃孵育30 min,DAB溶液顯色(鏡下控制),蘇木素復(fù)染5 min,梯度乙醇脫水,二甲苯透明,封片,鏡下觀察。Glu、GABA陽性細(xì)胞呈棕色,胞體呈圓形或橢圓形。顯微鏡下定位梨形皮質(zhì),使用Image-Pro-Plus6.0彩色圖像分析系統(tǒng)準(zhǔn)確分割陽性區(qū)域,檢測各組腦組織梨形皮質(zhì)Glu、GABA灰度值。
2.1 各組梨形皮質(zhì)神經(jīng)元損傷修復(fù)情況 尼氏染色結(jié)果顯示,對(duì)照組梨形皮質(zhì)神經(jīng)元形態(tài)正常,核膜、核仁清晰。模型組嗅球毀損24、72 h,梨形皮質(zhì)神經(jīng)元尼氏染色逐漸減弱,提示神經(jīng)元發(fā)生潰變;嗅球毀損7天,梨形皮質(zhì)神經(jīng)元尼氏染色較毀損24、72 h逐漸增強(qiáng),提示神經(jīng)元開始重建;玫瑰花蕾組梨形皮質(zhì)神經(jīng)元尼氏染色程度接近對(duì)照組水平。對(duì)照組梨形皮質(zhì)神經(jīng)元尼式小體灰度值為87.32±3.14,模型組毀損24 h、72 h、7 d、14 d時(shí)灰度值分別為101.76±4.52、110.76±2.78、98.35±2.69、94.26±3.01,玫瑰花蕾組為88.47±4.33;模型組毀損72 h時(shí)尼式小體灰度值大于對(duì)照組和玫瑰花蕾組(P均<0.05)。見插頁Ⅱ圖1。
2.2 各組梨形皮質(zhì)Glu、GABA表達(dá)比較 與對(duì)照組比較,模型組毀損72 h、7 d時(shí)梨形皮質(zhì)Glu表達(dá)減少、GABA表達(dá)增加;與模型組毀損72 h、7 d 比較,玫瑰花蕾組Glu表達(dá)增加、GABA表達(dá)減少;兩組比較P均<0.05。見表1。
表1 各組梨形皮質(zhì)Glu、GABA表達(dá)比較(灰度值,
注:與對(duì)照組比較,#P<0.05;與模型組7 d比較,*P<0.05;與模型組72 h比較,△P<0.05。
嗅球與多個(gè)嗅覺高級(jí)中樞之間存在廣泛的纖維聯(lián)系,從嗅球發(fā)出的僧帽細(xì)胞和叢狀細(xì)胞的軸突以嗅束的方式投射到初級(jí)嗅皮質(zhì)的嗅前核、嗅結(jié)節(jié)、梨形皮質(zhì)、扣帶回前區(qū)、內(nèi)側(cè)嗅皮層[5]。梨形皮質(zhì)是哺乳動(dòng)物嗅覺信息處理過程中到達(dá)的第一層皮質(zhì),是感知?dú)馕吨陵P(guān)重要的舊皮質(zhì)。梨形皮質(zhì)與周圍腦區(qū)的廣泛纖維聯(lián)系是其發(fā)揮正常生理功能和參與各種嗅覺信息處理的結(jié)構(gòu)基礎(chǔ)[6],一旦出現(xiàn)病變,將嚴(yán)重影響嗅覺信息的傳遞和處理[7,8];神經(jīng)退行性疾病如阿爾茨海默病患者對(duì)氣味識(shí)別障礙即源于梨形皮質(zhì)功能紊亂。神經(jīng)元的功能和尼氏小體密切相關(guān)。正常情況下各種神經(jīng)元的尼氏小體均有其特定的數(shù)量和特征性的形態(tài)分布,而在病理狀態(tài)下(如神經(jīng)元發(fā)生潰變時(shí))尼氏小體減少甚至消失[9]。目前達(dá)成共識(shí)的成年哺乳動(dòng)物神經(jīng)系統(tǒng)中神經(jīng)元再生重建的區(qū)域是室管膜下區(qū)和海馬齒狀回。Sahay等[10]認(rèn)為,齒狀回神經(jīng)再生對(duì)一系列依賴海馬的認(rèn)知功能非常重要。Lepousez等[11]研究表明,室管膜下區(qū)神經(jīng)再生可調(diào)節(jié)嗅覺,修復(fù)皮層損傷,防御潰變向更高的嗅覺處理中心擴(kuò)散。梨形皮質(zhì)具有神經(jīng)再生的潛能,嗅球毀損后出現(xiàn)的新生神經(jīng)元可能會(huì)在梨形皮質(zhì)第二層最終分化為錐體神經(jīng)元。與海馬和室管膜下區(qū)相比,嗅覺皮質(zhì)區(qū)域的梨形皮質(zhì)神經(jīng)元再生受到的關(guān)注較少,但其在嗅覺傳導(dǎo)過程中的重要作用無可替代。在癲癇和退行性神經(jīng)病變的病理過程中常伴隨嗅覺的損傷和梨形皮質(zhì)形態(tài)的改變。有研究指出,梨形皮質(zhì)中聯(lián)合突觸的可塑性存在于小鼠的整個(gè)生命歷程中,無論是在早期關(guān)鍵期還是在關(guān)鍵期之外,聯(lián)合突觸的可塑性都未曾改變[12]。本研究采用探針破壞大鼠嗅球,通過尼氏染色發(fā)現(xiàn)損傷后24、72 h梨形皮質(zhì)(尤其是第二層)大量錐體細(xì)胞發(fā)生潰變,尼式染色減弱,尼式小體數(shù)量減少;損傷7 d時(shí)梨形皮質(zhì)錐體細(xì)胞潰變后重建,尼式小體染色逐漸增強(qiáng),尼式小體數(shù)量有所增加;上述結(jié)果提示,損毀嗅球可導(dǎo)致梨形皮層神經(jīng)元發(fā)生損傷,但損傷神經(jīng)元可再生、自行修復(fù),說明梨形皮層神經(jīng)元具有損傷后再生能力。
芳香療法是通過芳香物質(zhì)中的小分子物質(zhì)(芳香小分子)刺激嗅覺來達(dá)到對(duì)嗅覺的調(diào)節(jié)及對(duì)嗅覺信息傳遞的促進(jìn)作用。精油是從芳香植物中蒸餾萃取出來的,是分子量很小的活性混合物,具有高滲透性、高揮發(fā)性、高流動(dòng)性等特點(diǎn),可通過呼吸進(jìn)入動(dòng)物和人體內(nèi)。玫瑰花蕾萃取物為芳香療法常用芳香物質(zhì),是由多種芳香族化合物組成的混合物,其主要成分為芳樟醇、香茅醇甲酸酯、牻牛兒醇、玫瑰醚、乙酸乙酯、苯甲醇、甲基丁香油脂、十五烷、β-苯乙醇、橙花醇、α-白蘇烯、β-突厥酮等[13,14]。芳香小分子可以通過嗅覺通路直接刺激下丘腦垂體,進(jìn)而分泌激素及神經(jīng)調(diào)節(jié)物質(zhì)等,以調(diào)節(jié)機(jī)體功能。Igarashi等[15]研究發(fā)現(xiàn),玫瑰精油(主要成分為玫瑰花蕾萃取物)可使人在生理和心理上感到放松,增加大腦皮質(zhì)活動(dòng)。Kiecolt Glaser等[16]研究發(fā)現(xiàn),芳香小分子可恢復(fù)刺激誘導(dǎo)的免疫抑制,調(diào)節(jié)神經(jīng)內(nèi)分泌。本實(shí)驗(yàn)室前期研究發(fā)現(xiàn),芳香物質(zhì)吸嗅對(duì)改善嗅覺通路有益[17]。本研究中玫瑰花蕾組梨形皮質(zhì)神經(jīng)元尼氏染色程度接近對(duì)照組水平,提示玫瑰花蕾萃取物吸嗅能促進(jìn)嗅球毀損后梨形皮質(zhì)神經(jīng)元再生,對(duì)嗅球損傷后的嗅覺通路修復(fù)具有一定的促進(jìn)作用。
中樞神經(jīng)系統(tǒng)中含有多種神經(jīng)遞質(zhì),其相互協(xié)調(diào)、相互作用,構(gòu)建神經(jīng)遞質(zhì)平衡系統(tǒng),維持機(jī)體各種生理活動(dòng)的穩(wěn)定。其中興奮性神經(jīng)遞質(zhì)Glu和抑制性神經(jīng)遞質(zhì)GABA參與嗅覺的形成與傳導(dǎo)[18],二者在嗅球和梨形皮質(zhì)發(fā)揮正常生理功能和可塑性方面非常重要[19]。嗅球毀損可引起嗅覺通路的改變及神經(jīng)遞質(zhì)的變化,嗅球毀損后不同腦區(qū)Glu、GABA神經(jīng)元對(duì)刺激的反應(yīng)各不相同。本研究結(jié)果顯示,模型組嗅球毀損24、72 h梨形皮質(zhì)Glu表達(dá)減少、GABA表達(dá)增加,原因主要為嗅球受損導(dǎo)致鄰近神經(jīng)組織興奮性增強(qiáng),促進(jìn)Glu釋放、抑制GABA釋放,誘導(dǎo)興奮性毒性損傷,進(jìn)一步加重梨形皮質(zhì)神經(jīng)元的損傷;與毀損嗅球24、72 h比較,毀損嗅球7、14 d時(shí)梨形皮質(zhì)Glu表達(dá)逐漸增加、GABA表達(dá)逐漸降低,提示隨著神經(jīng)元的再生修復(fù),Glu釋放逐漸減少、GABA釋放逐漸增多,興奮性毒性損傷逐漸降低;玫瑰花蕾組Glu及GABA表達(dá)與對(duì)照組比較無統(tǒng)計(jì)學(xué)差異,且GABA表達(dá)高于模型組嗅球毀損14 d、GABA表達(dá)低于模型組嗅球毀損14 d,提示玫瑰花蕾萃取物吸嗅可抑制Glu釋放、促進(jìn)GABA釋放。
綜上所述,玫瑰花蕾萃取物吸嗅對(duì)嗅球毀損大鼠梨形皮質(zhì)神經(jīng)元損傷修復(fù)具有促進(jìn)作用,抑制Glu釋放、促進(jìn)GABA釋放可能是其作用機(jī)制。
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Effect of rosebud extracts on piriform cortical neuronal damage and repair in olfactory bulb damaged rats and its mechanism
BIANLincui,WANGMin,HELimin,XUJinyong,LIGuangwu
(InstituteofNeurobiologyofAnhuiMedicalUniversity,Hefei230032,China)
Objective To investigate the effect of rosebud extracts on piriform cortical neuronal damage and repair in olfactory bulb damaged rats and its mechanism. Methods Healthy adult male SD rats were randomly divided into three groups, namely the control group (n=10), model group (n=40) and rosebud group (n=10). Rats in the control group were not treated. Using probes agitation to damage the olfactory bulb of rats in the model group and rosebud group. One day after the damage of the olfactory bulb, rats in the rosebud group were prepared to smell rosebud extracts, each time for 1 h, twice a day and for 14 d. The brain tissues were collected from rats in the model group after the damage of the olfactory bulb 24 h, 72 h, 7 d and 14 d (each time, ten rats) as well as the rosebud group 14 d after the damage. After conventional section, we used Nissl staining to detect the piriform cortical neuronal damage and repair. Immunohistochemical staining was carried out to detect the Glu and GABA expression of piriform cortex. Results The Nissl body gray value of the control group was 87.32±3.14, and they were respectively 101.76±4.52, 110.76±2.78, 98.35±2.69 and 94.26±3.01 after olfactory bulb damage of 24 h, 72 h, 7 d and 14 d. The rosebud group was 88.47±4.33, and the Nissl body gray value in 72 h after olfactory bulb damage was higher than that of the control group (allP<0.05). Compared with the control group, the Glu expression gray value of piriform cortex at 72 h and 7 d after olfactory bulb damage was decreased, but the GABA expression gray value was increased in the model group. The Glu expression gray value of piriform cortex was increased and the GABA expression gray value was decreased in the rosebud group as compared with that of the model group at 72 h and 7 d after olfactory bulb damage. Significant difference was found between these two groups (allP<0.05). Conclusion Rosebud extracts play an important role in promoting the piriform cortical neuronal damage and repair in olfactory bulb damaged rats, and its mechanism may be associated with the inhibiting release of Glu, and promoting release of GABA.
rosebud extracts; olfactory bulb damage; piriform cortical; neurotransmitter; olfactory pathway; neurogenesis
國家自然科學(xué)基金資助項(xiàng)目(81000589)。
卞林翠(1991-),女,在讀碩士,研究方向?yàn)樾嵊X通路與芳香療法。E-mail: Lincuibian@163.com
李光武(1962-),男,副教授,研究方向?yàn)樾嵊X通路與芳香療法、神經(jīng)藥理學(xué)等。E-mail: guangwuli@sina.com
10.3969/j.issn.1002-266X.2016.28.002
R493
A
1002-266X(2016)28-0005-04
2016-01-19)