Brain Research 888 2001 11–18 www.elsevier.com locate bres
Research report
Protective effect of green tea extract on ischemia reperfusion-induced brain injury in Mongolian gerbils
a , a
a a
a
Jin Tae Hong , Seung Rel Ryu , Hye Jin Kim , Jong Kwon Lee , Sun Hee Lee ,
b c
a
Yeo Pyo Yun , Byung Mu Lee , Pu Young Kim
a
National Institute of Toxicological Research , Korea Food and Drug Administration, 5, Nokbun-dong, Eunpyung-gu, Seoul, 122-704, South Korea
b
College of Pharmacy , Chungbuk National University, 48, Gaesin-Dong, Heungduk-Gu, Cheongju, Chungbuk, 361-763, South Korea
c
Division of Toxicology , College of Pharmacy, SengKyunKwan University, Chunchun-dong 300, Suwon, Kyunggido, 440-746, South Korea
Accepted 29 August 2000
Abstract
Free radical-induced oxidative damages of macromolecules and cell death are important factors in the pathogenesis of ischemia reperfusion brain injury. In the present study, an investigation as to whether green tea extract reduces ischemia reperfusion-induced brain
injury in Mongolian gerbils was conducted. The effect of green tea on the ischemia reperfusion-induced production of hydrogen peroxide, lipid peroxidation and oxidative DNA damage formation of 8-hydroxydeoxyguanosine, and cell death in addition to locomotor activity
was studied. Two doses 0.5 or 2 of green tea extract were added into the drinking water and to be accessed by animals ad libitum for 3 weeks prior to the induction of ischemia. A global ischemia was induced by the bilateral occlusion of the common carotid arteries for 5
min. Reperfusion was achieved by releasing the occlusion and restoring blood circulation for 48 h. The infarction volumes were 112631
3 3
3
mm and 76611 mm in the 0.5 and 2 green tea pretreated animals compared to 189612 mm in the ischemia reperfusion animals. Green tea extract also reduced the levels of ischemia reperfusion-induced hydrogen peroxide from 14706170 to 1034646 and 555630
nmole mg protein, lipid peroxidation products from 14106210 to 930640 and 330620 nmole mg protein and 8-oxodG from 3.960.1
22
to 2.860.3 and1.960.3 ng mg DNA, 310 by pretreatment of 0.5 or 2 green tea for 3 weeks, respectively. Moreover, green tea also
reduced the number of ischemia reperfusion-induced apoptotic cells from 59612 to 3768, 15611 apoptotic cells high power field in the striatum region and locomotor activity from 1514062940 to 39006600 and 410061200. This study therefore suggests that green
tea may be a useful agent for the prevention of cerebral ischemia damage.
2001 Elsevier Science B.V. All rights reserved.
Keywords : Green Tea extract; Ischemia reperfusion; Oxidative damage; Gerbil
1. Introduction The formation of these oxidation products in the human
brain increases with age and ischemia reperfusion animal It is generally believed that ischemia reperfusion-me-
brain [15,24]. It is therefore of interest to study the effects diated brain injury results, at least in part, from the
of antioxidants, free radical scavengers or trapping agents oxidation of cellular macromolecules [21]. Because of the
for use as potential cerebroprotective agents of various brain’s high consumption of oxygen, high concentration of
brain injuries including ischemia reperfusion-mediated polyunsaturated fatty acid and transition metals, and low
brain injury. concentration of antioxidants, it is vulnerable to ischemia
Green tea has been reported to have antioxidant prop- reperfusion-induced reactive oxygen species which cause
erties [19]. Green tea reduces iron-induced lipid peroxida- oxidative damage to lipids and brain DNA. The formation
tion in brain homogenates as well as in cultured C6 of lipids and DNA oxidation products e.g. malondial-
astrocytes and lung cells [13,14,27,11]. In addition, green dehyde and 8-hydroxydeoxyguanosine have been found to
tea has also been shown to reduce the formation of the cause cellular dysfunction or and cell death, which leads
spin-adducts of hydroxyl radicals and hydroxyl radical- to further impairment of the central nervous system [7].
induced DNA strand breakage in vitro [6] in addition to UV radiation-induced oxidative DNA damage in calf
thymus DNA [23]. Moreover, green tea has been found to
Corresponding author. Tel.: 182-2-380-1783; fax: 182-2-380-1786. E-mail address
: jinthongkfda.go.kr J.T. Hong.
have inhibitory effects on the UVB light-induced skin [20]
0006-8993 01 – see front matter
2001 Elsevier Science B.V. All rights reserved. P I I : S 0 0 0 6 - 8 9 9 3 0 0 0 2 9 3 5 - 8
12 J
and chemical-induced lung tumorigenesis [25]. There is each brain slice was defined by the 2,3,5-triphenyltet-
also considerable epidemiological evidence suggesting that razolium chloride TTC staining method. After 48 h
the consumption of green tea lowers the risk of heart reperfusion, the gerbils received an intracardiac perfusion
disease as well as several types of cancer incidences as a of 0.9 buffered saline. The brain was then removed, and
result of these antioxidant mechanisms [1]. cut into 2-mm serial slices starting 1 mm from frontal pole.
In the present study, the protective effect that green tea The coronal slices were then immersed in a 2 phosphate-
extract has on ischemia reperfusion-induced brain injury buffered solution for 50 min at 378C. After TTC staining,
was examined. In particular, the ischemia reperfusion- the slices were fixed in 10 phosphate-buffered formalin
induced production of hydrogen peroxide, lipid peroxida- and the infarction area was then determined by an image
tion and oxidative DNA damage formation of 8-hydroxy- analyzer using the leicaQwin programme Leica Mi-
deoxyguanosine, and cell death as well as locomotor crosystem Image Solution Ltd., Cambridge, UK. The
2
activity on the Mongolian gerbil were focused. infarct area mm from each thicken-brain slice was
3
determined, and the infarct volume mm was calculated from sum of the slice areas 7 slices in all3thickness 2
2. Materials and methods mm.
