奈米與次微米枸杞對大鼠視網膜缺血再灌流病變模式之神經保護效力

The Neuroprotective Effect of Nano/submicron and Blended Lycium barbarum for Experiment Retinal Ischemia and Reperfusion Injury in Rats

吳依涵(I-Han Wu)

指導教授 ： 林中天

國立臺灣大學/獸醫專業學院/臨床動物醫學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.01858

摘要

青光眼因為高眼壓會造成視網膜缺血並導致視神經傷害進而視神經細胞死亡。在亞洲國家，枸杞被認為有滋肝補腎與改善視力的功能已經超過2500年之久，此外，近年來奈米技術一直是個熱門話題，認為更小的粒子可能具有更多的有效生物利用度，值得進一步的研究。介質研磨的方式，可以將物質的粒徑減小到奈米/次微米等級，使物質具有較高生物活性成分（膳食纖維，總類胡蘿蔔素，β物胡蘿蔔素和粗多醣）之萃取效率。
為了了解不同粒徑的中草藥枸杞在青光眼高眼壓導致的視網膜缺血、神經細胞的死亡和氧化性傷害等之保護效果，我們建立高眼壓大鼠動物模式，並分析高眼壓大鼠動物模式之視網膜病變特徵，作為青光眼和視網膜缺血傷害之預防與治療研究的基礎。本實驗成功建立穩定高眼壓視網膜缺血大鼠模式，並分析高眼壓大鼠動物模式之視網膜病變特徵，利用視網膜電波圖測量、組織病理學分析、抗氧化物（總麩胱甘肽、超氧化物歧化酶、過氧化氫酶）與脂質過氧化產物丙二醛之濃度測定，評估奈米/次微米枸杞對於實驗性視網膜缺血動物模式造成的視網膜傷害是否具有神經保護之功能。
投予不同粒徑大小不同劑量（細碎非奈米化、介質研磨奈米化；500 mg/kg、250 mg/kg、100 mg/kg）之枸杞，評估是否對於視網膜缺血性病變有神經保護與對抗氧化傷害的效果。所有枸杞治療組的視網膜電波a波與b波相較於高眼壓視網膜缺血大鼠的未治療組都有保留波幅的效果: a波可以保留約55~60%的波幅，b波可以保留約43~62%的波幅。所有枸杞治療組對於視網膜缺血病變都具有保留視網膜功能的作用。其中以250 mg/kg之介質研磨奈米化枸杞對於視網膜電波圖b波具有最好的保護效果。
在抗氧化傷害方面，不同粒徑大小不同劑量枸杞對於視網膜內抗氧化物（總麩胱甘肽、超氧化物歧化酶、過氧化氫酶）相較於高眼壓視網膜缺血大鼠未治療組均有提升，而代表氧化壓力之脂質過氧化產物丙二醛相較於高眼壓視網膜缺血大鼠未治療組皆有下降，不管細碎非奈米化或是介質研磨奈米化枸杞皆具有保護視網膜的效果。整體來說，250 mg/kg之介質研磨奈米化枸杞與500 mg/kg之細碎非奈米化枸杞相較與其他實驗組，具有最好的抗氧化效果。在血漿中，抗氧化物總麩胱甘肽與過氧化氫酶在傷害未治療組與各治療組間並未見明顯差異，在超氧化物歧化酶與脂質過氧化產物丙二醛則可觀察到投予枸杞皆具有提升抗氧化酵素與降低氧化傷害的能力。綜合結果顯示，枸杞在高眼壓視網膜缺血時對視網膜結構型態及功能與對抗氧化傷害能力上均發現有保護的效果，尤以250 mg/kg之介質研磨奈米化枸杞之保護效果最佳。

關鍵字

視網膜病變、青光眼、視網膜缺血、奈米技術、神經保護、枸杞、抗氧化

並列摘要

Ocular hypertension or glaucoma results in retinal ischemia and consequent death of optical neural cells. Lycium barbarum (LB) has been known for nourishing the liver and kidney, improving visual acuity for more than 2,500 years in oriental countries. Further, nanotechnology has been minimize particle size in order to achieve more effective bioavailability. Media milling of LB who used to reduce the material size to nano/submicron scale, which was attributed to higher extractive efficiency of bioactive components (dietary fiber, total carotenoids, beta-carotene and crude polysaccharides).
To evaluate the neuroprotective effect of the Chinese herb Lycium barbarum with different particle sizes, we established an experimental rat model of ocular hypertension to evaluate features of retinal ischemia as a basis of further research in prevention and management of retinal ischemia. A stable animal model of ocular hypertension has been successfully established and characterized in the rat. In this study, we adopted electroretinography (ERG), histopathological analysis, and assayed for levels of antioxidants (Reduced glutathione and glutathione, GSH and GSSH), antioxidative enzymes (Catalase and superoxide dismutase, SOD) and peroxidants (Malondialdehyde, MDA) to evaluate the neuroprotective effect of nano/submicron LB on retinal functions in an experimental model of retinal ischemia.
With different particle sizes (blended or milled) and different doses (500 mg/kg、250 mg/kg、100 mg/kg) of LB, we evaluated its neural protective and antioxidative effects on retinal ischemia. The amplitude of a and b waves were preserved in rats treated with blended or milled LB groups of different doses compared with untreated group in a wave (55-60%) and b wave (43-62%). In all LB treated groups, the preservation of retinal function following retinal ischemia was observed. The best neuroprotective effect in b-wave amplitudes of ERG was observed in the 250 mg/kg milled LB group. In terms of antioxidative capacity of retina, levels of GSSH+GSH, SOD, and catalase of all LB groups were higher than those in untreated groups, and the MDA was lower than that in untreated groups. Blended and milled L. barbarum both protected retina. To sum up, the better antioxidative effect was observed in the 250 mg/kg milled and 500 mg/kg blended LB than other group. In the plasma, there was no significant difference in levels of GSSH+GSH and catalase between the LB treated groups and untreated groups. There was higher levels of SOD and lower levels of MDA in the plasma of LB treated groups compared with untreated group.
In conclusion, LB, especially 250 mg/kg milled LB, provided retinal neuroprotective effects in preservation of retinal structure and function with improved antioxidative capacity in the rats with high intraocular pressure induced retinal ischemia.

並列關鍵字

Retinopathy, Glaucoma, Retinal ischemia, Nanotechnology, Neuroprotection, Lycium barbarum, Antioxidant

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