J. ENVIRON. TOXICOL. Vol. 21, No. 2, 139~146 (2006) Streptozotocin 으로유발된당뇨쥐에서청국장분말의항당뇨및항산화효과 김혜정, 김영철 계명대학교공중보건학과 Antidiabetic and Antioxidant Effects of Chunggugjang Powder in Streptozotocin-Induced Diabetic Rats Hye Jong Kim and Youngchul Kim Department of Public Health, Keimyung University, Daegu 702-701, Korea ABSTRACT The purpose of this study was to investigate the effects of dietary chunggugjang powder on blood glucose level and hepatic activities of antioxidant enzymes in normal and streptozotocin (STZ)-induced diabetic rats. Sprague-Dawley male rats (200~220 g) of six groups including normal group fed normal diet (N), diabetic group fed normal diet (C), diabetic groups fed chunggugjang powder diet (DC-1%, DC-5%, DC-10%, DC- 20%) were used for the experiments. Diabetes was induced by single intraperitoneal injection of streptozotocin as a dose of 70 mg/kg body weight. After 3 weeks the animals were sacrificed and hepatic activities of antioxidant enzymes, serum level of glucose and organ weight were evaluated. Food and water intakes were higher in diabetic groups than normal group. Body weight gain and food efficiency ratio were lower in diabetic groups. However, they were higher in chunggugjang diet groups (DC) than normal diet group (C). The serum glucose levels were significantly lower (p 0.05) in the diabetic groups fed chunggugjang diet (DC-10%, DC-20%) than diabetic group fed normal diet (C). Hepatic activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione S-transferase were lower in diabetic groups than normal group and they were significantly lower in diabetic groups fed chunggugjang diet (DC-20%) compared to diabetic rats fed normal diet (p 0.05). In conclusion, these results indicated that chunggugjang powder would have antidiabetic and antioxidant effects in STZ-induced diabetic rats. Key words : Chunggugjang, streptozotocin, diabetic rats, antidiabetic effects 서 론 현대과학의큰발전에도불구하고당뇨병의발 To whom correspondence should be addressed. Tel: +82-53-580-5931, Fax: +82-53-588-5233 E-mail: yckim@kmu.ac.kr 병률은증가하고있으며그예방과치료에대한관심이집중되고있다. 당뇨병은췌장에있는 Langerhans 섬의 β-cell 에서분비되는 insulin 의생리작용이저조하거나 insulin receptor 의수가적어 insulin 의생리적기능이불충분할때나타나는혈당증이다 (Rayfield and Ishimura, 1987). 인슐린의존 139
140 J. ENVIRON. TOXICOL. Vol. 21, No. 2 형당뇨병 (type I diabetes) 은당뇨병환자의약 10% 가이경우에속하며주로췌장의이상으로인슐린이생성되지않아발병한다. 인슐린비의존형당뇨병 (type II diabetes) 은식사후췌장에서인슐린의분비가적고분비속도가늦거나, 신체조직세포에서인슐린작용에대한저항성이증대되어고혈당을초래하여발병한다. 당뇨병의주요대사적특징은혈당농도의상승과지질대사의비정상성 (Coulston and Hollenbeck, 1988) 으로써혈중지단백과유리지방산의농도상승으로고지혈증을초래하여주요합병증인관상동맥질환 (West et al., 1983) 을일으키며망막증, 고혈압등만성당뇨합병증을일으키기도하는데최근에는이러한당뇨의합병증에산화적스트레스가관여한다는보고 (Baynes, 1991) 가있다. 인체는정상적인생리상태에서는자유라디칼 (free radical) 의생산과항산화방어체계 (antioxidant defense system) 의활성이균형을이루고있으며체내에서자유라디칼이과다생성되거나혹은항산화방어계의기능이감소되어균형이깨지면서산화적스트레스가일어난다 (Lawrence et al., 2001). 당뇨병환자에서산화적스트레스가증가하는주요원인은비효소적당화반응과자동산화적당화반응의증가와항산화방어체계의손상등으로추측하고있다 (Lee et al., 2001) 이러한당뇨병의치료및합병증예방을위해최근에는다양한생리활성을갖고있는기능성식품을이용한연구가시도되고있다. 뽕잎은항산화물질인 rutin, quercetin, isoquercetin 같은플라보노이드, GABA (γ-aminobutyric acid) 등의기능성물질이함유되어있어혈당저하작용이나혈액중의중성지방과콜레스테롤저하작용, 동맥경화증및고지혈증등의치료에효과가있는것으로알려져있다 (Chae et al., 2003). 콩은식물성단백질로콜레스테롤, 중성지방저하효과가현저하며, 식이섬유, 비타민 E, 이소플라본, 페놀, 사포닌, 트립신저해제, 피틴산등이함유되어있고혈당지수를낮추어 (Friedbwald and Ruhrah, 1990) 당뇨의예방및치료에효과가있는것으로보고되었다 (Kim et al., 2001). 콩을이용한우리나라전통발효식품의하나인청국장은단백질의소화흡수가용이하고특유의점질성조직감과구수한풍미를지니고있으면서 정장작용과함께간장을보호해주는작용이있다고알려지고있다 ( 정태석등, 1959). 이에이연구에서는뽕나무로우려낸물에콩을삶아발효시켜만든뽕청국장을이용하여 streptozotocin 으로유발된당뇨병랫드의혈당변화와항산화계에미치는영향을살펴보고자하였다. 1. 실험동물 재료및방법 실험동물은 Sprague-Dawley 랫드 (200~220g) 수컷을 ( 주 ) 효창사이언스로부터분양받아 1 주일적응시킨후난괴법에의해 6 군 ( 정상식이군, 당뇨정상식이군, 당뇨청국장 1% 군, 당뇨청국장 5% 군, 당뇨청국장 10% 군, 당뇨청국장 20% 군 ) 으로나누어각군당 4 마리씩 3 주간사육하여실험하였다. 사료섭취량과물은매일, 체중은주 1 회, 혈당은매주아침 9:00~10 : 00 시에측정하였다. 2. 당뇨유발 인슐린의존성당뇨병과유사한실험동물을만들기위하여 streptozotocin (STZ, Sigma 사, USA) 을 0.4 M citrate buffer 용액에용해시켜 70 mg/kg body weight 용량 (0.5 ml/100 g body weight) 으로복강내주사하였다. 당뇨유발확인은 STZ 주사 72 시간후측미정맥에서채혈하여혈당량이 300 mg/dl 이상이면당뇨병이유발된것으로간주하였다. 3. 실험식이조성 청국장분말의일반성분함량을분석 ( 조단백 34.6%, 조지방 25.1%, 조섬유 0.5%, 회분 4.7%, 당질 26.3%, 수분 8.8%) 하여 AIN-76 diet 를기본으로대조군과실험군의식이조성을조정하였다 (Table 1). 식이제조에사용한 casein 은 Fonterra 사 (New Zealand) 제품을사용하였으며 DL-Methionine, choline bitartrate 및 cellulose 는 Sigma 사 (USA) 제품을사용하였고 AIN-76 vitamin mixture 와 AIN- 76 mineral mixture 는 Dyets 사 (USA) 제품을사용하였으며 corn starch, sucrose, corn oil, 청국장은각각삼양제넥스, 삼양사, 제일제당, 홍성림 (Korea) 제품
June 2006 Kim and Kim : Effects of Chunggugjang Powder in Diabetic Rats 141 Table 1. Composition of experimental diets (%) Normal diet Chunggug Chunggug Chunggug Chunggug jang-1% jang-5% jang-10% jang-20% Casein 20.00 19.65 18.27 16.55 13.09 DL-Methionine 0.30 0.30 0.30 0.30 0.30 Choline bitartrate 0.20 0.20 0.20 0.20 0.20 Corn starch 15.00 14.94 14.70 14.39 13.79 Sucrose 50.00 49.71 48.54 47.08 44.15 Cellulose 5.00 5.00 4.98 4.95 4.91 Mineral mix 3.50 3.45 3.27 3.03 2.56 Vitamin mix 1.00 1.00 1.00 1.00 1.00 Corn oil 5.00 4.75 3.75 2.49 - Chunggugjang - 1.00 5.00 10.00 20.00 Total 100.00 100.00 100.00 100.00 100.00 을사용하였다. 4. 혈당측정 실험기간동안매주동일시간에측미정맥에서혈액을채취하여혈당계 Gluco Dr super sensor (Allmedicus 사, Korea) 로혈당을측정하였으며분리한혈청의 glucose 농도는에이껜사의시약을사용하여 Hitachi 7170 (Hitachi 사, Japan) 으로측정하였고 insulin 농도는 ELISA kit (Mercodai 사, USA) 를이용하여 microplate reader (Molecular devices 사, USA) 로측정하였다. 5. 실험동물처치 실험사육한랫드를 14 시간동안절식시킨후 21 일째날에 ether 마취하에복부대동맥에서혈액을채취하여실온에서 30 분방치한후 3,000 rpm 에서 30 분간원심분리하여혈청을분리한후 glucose 와 insulin 농도측정에사용하였다. 장기는채혈후즉시적출하여생리식염수로씻어내고수분을여과지로제거한후무게를칭량하였다. 간조직은생리식염수로관류시켜조직내혈액을제거하고일정량을칭량한후 4 배량의 0.25 M sucrose 용액을넣고 glass teflon homogenizer 를이용하여 20% (w/v) 마쇄균질액을만들었다. 이균질액을 600 g 에서 10 분간원심분리하여핵및미마쇄부분을제거한상층액을 10,000 g 에서 20 분간원심분리한후효소활성측정시료로사용하였다. 6. 간조직의효소활성도측정 1) Superoxide dismutase (SOD) SOD 의활성도는 hematoxylin 자동산화의억제정도를관찰하는 Martin 등 (1987) 의방법에따라 0.1 mm EDTA 가함유된 50 mm 인산완충액 (ph 7.5) 에 10 µm hematoxylin 및효소액을가해 25 C 에서반응시켜생성된 hematein 을 560 nm 에서측정하여효소의활성도를산정하였다. 활성도단위는효소액을넣지않은반응액중의 hematoxylin 자동산화를 50% 억제하는정도를 1 unit 로하여단백질 1mg 이 1 분동안반응한 unit 로표시하였다. 2) Catalase (CAT) CAT 활성도는 hydrogen peroxide 를기질로하여환원되는정도를파장 240 nm 에서흡광도를읽고분자흡광계수 (E=0.04 mm -1 cm -1 ) 를이용하여활성을산출하는 Aebi (1974) 의방법에준하였다. 활성도단위는간조직중에함유된단백질 1mg 이 1 분동안반응하여감소되는 hydrogen peroxide 의양을 nmole 로표시하였다. 3) Glutathione peroxidase (GPX) GPX 의활성도는 Paglia 와 Valentine (1967) 의방법에따라측정하였다. Glutathione 기질과조효소인 NADPH 를시료와함께 25 C 에서 5 분간반응시켜 340 nm 에서 NADPH 의산화로인한흡광도감소율을측정하였다. 활성도단위는효소반응액중에함유된단백질 1mg 이 1 분간산화시킨 NADPH 의양을 nmole 로표시하였다.
142 J. ENVIRON. TOXICOL. Vol. 21, No. 2 Table 2. Water intake, food intake, body weight gain and food efficiency ratio of STZ-induced diabetic rats Groups 1) Items N C DC-1 DC-5 DC-10 DC-20 Water intake (ml/day) 29.2±1.41 273.50±12.48 ## 272.00±8.52 ## 269.50±4.93 ## 269.00±1.63 ## 268.00±4.97 ## Food intake (g/day) 19.20±0.63 34.93±2.34 ## 34.58±1.42 ## 34.43±1.77 ## 38.49±0.78 ## * 37.53±0.49 ## Body weight gain (g) 93.50±3.54-17.00±14.21 ## -18.25±13.65 ## -14.25±25.02 ## -0.75±6.34 ## -3.25±11.0 ## Food efficiency ratio 2) (%) 4.68±0.34-0.48±0.37 ## -0.52±0.37 ## -0.44±0.78 ## -0.02±0.16 ## -0.09±0.29 ## 1) N : Normal-Normal diet, C : Diabetes-Normal diet, DC-1: Diabetes-Chunggugjang 1% diet, DC-5: Diabetes-Chunggugjang 5% diet, DC- 10: Diabetes-Chunggugjang 10% diet, DC-20: Diabetes-Chunggugjang 20% diet. 2) Food efficiency ratio: body weight gain/food intake,values are mean±sd of 4 rats. ## Significantly different from the normal group by t-test (p 0.01). *Significantly different from the diabetes-normal group by t-test (p 0.05). 4) Glutathione S-transferase (GST) GST 의활성도는 Habig 등 (1974) 의방법에따라측정하였다. 1-chloro-2, 4-dinitrobenzene 과 glutathione 을기질로하여 25 C 에서 10 분간반응시켜생성된 2, 4-dinitrobenzene-glutathione conjugate 양을 340 nm 에서측정하였다. 활성도단위는효소반응액중에함유된단백질 1mg 이 1 분간반응하여생성시킨 conjugate 의양을 nmole 로나타내었다. 5) 간조직의단백질함량측정간조직중단백질함량은 Lowry 등 (1951) 의방법에따라 bovine serum albumin 을표준품으로사용하여측정하였다. 7. 자료분석 SPSS (v12.0) 통계프로그램을이용하여정상군, 당뇨정상식이군, 당뇨청국장식이군간의분석자료의비교를위하여 t-test 로분석하였다. 통계적유의수준은 0.05 로하였다. 결과및고찰 1. 물, 식이섭취량및식이효율 실험식이로 3 주간사육한당뇨쥐의물섭취량, 식이섭취량및식이효율을측정한결과는 Table 2 와같다. 음수량은당뇨군이정상군에비해현저하 Body weight gain (g) 120.0 100.0 80.0 60.0 40.0 20.0 0.0-20.0-40.0-60.0 ## ## 게높았으며 ( 약 9 배 ), 식이섭취량은당뇨군이정상군에비해약 2 배높았다. Park 등 (1994) 도 streptozotocin (STZ) 에의해유발된당뇨쥐는정상쥐에비해식이섭취량이 1.5~2 배되는다식증상이있다고보고한바있다. 체중은정상군은지속적인증가추세를보인반면당뇨대조군은감소하는현상을보였으며 (Fig. 1), STZ 에의해췌장의 β-cell 이파괴되어당대사의불균형을초래한당뇨쥐는체중이쉽게회복되지않는것으로알려져있다 (Lee et al., 1994). 당뇨대조군에비해청국장 10% 와 20% 식이군은체중 ## ## N C DC-1 DC-5 DC-10 DC-20 Fig. 1. Body weight gain of diabetic rats fed the experimental diets for 3 weeks. Values are mean±sd of 4 rats. ## Significantly different from the normal group by t-test (p 0.01). ##
June 2006 Kim and Kim : Effects of Chunggugjang Powder in Diabetic Rats 143 Table 3. Changes in blood glucose of diabetic rats fed the experimental diets for 3 weeks Weeks N C DC-1 DC-5 DC-10 DC-20 0 122.00±5.67 794.33±97.11 ## 795.67±103.03 ## 812.25±120.97 ## 795.50±151.43 ## 785.00±182.98 # 1 103.50±2.12 1050.33±419.32 # 771.67±117.19 ## 1089.00±301.92 # 889.25±53.04 ## 837.67±36.69 ## 2 107.00±11.31 971.67±340.21 # 1262.67±164.61 ## 1126.50±364.56 # 1114.50±416.23 # 922.33±257.83 # 3 71.50±2.12 732.33±58.71 ## 716.67±73.71 ## 614.75±38.13 ## 675.00±35.36 ## 675.67±119.97 ## Values are mean±sd of 4 rats, Unit: mg/dl The value with a sharp-note is significantly different from the normal group by t-test ( # : p 0.05, ## : p 0.01). Table 4. Serum glucose and insulin levels of diabetic rats fed the experimental diets for 3 weeks Items N C DC-1 DC-5 DC-10 DC-20 Glucose (mg/dl) 151.50±3.54 814.75±57.71 ## 716.33±65.55 ## 755.00±81.06 ## 723.75±28.27 ## * 711.00±42.79 ## * Insulin (pmol/l) 132.59±0.54 56.25±0.49 ## 54.61±2.40 ## 54.52±1.38 ## 57.36±3.04 ## 55.65±2.41 ## Values are mean±sd of 4 rats. ## Significantly different from the normal group by t-test (p 0.01). *Significantly different from the diabetes-normal group by t-test (p 0.05). 감소율이낮았으며, 식이효율또한유사한경향을나타내었다. 이는기능성식품을당뇨동물에급여함으로써체중감소를방지하는효과도얻을수있음을 (Ko et al., 2002) 시사해준다. 2. 혈당, 혈청포도당및인슐린농도 혈중포도당농도변화는 Table 3 과같다. 정상군에비해당뇨대조군의초기혈당농도는약 6.5 배높았으며실험 3 주후당뇨정상식이군 (C) 은초기혈당에비해 7.8% 감소한반면청국장 1% 식이군 (DC-1) 은 9.9%, 청국장 5% 식이군 (DC-5) 은 24.3%, 청국장 10% 식이군 (DC-10) 은 15.2%, 청국장 20% 식이군 (DC-20) 은 13.9% 로혈당강하효과가있었으나통계적으로유의하지는않았다. STZ 로유도된당뇨쥐에서 STZ 투여가췌장 Langerhans 섬의 β-cell 을파괴하여인슐린분비가감소되며이로인해당질대사가비정상으로되어당이용률은줄어드는반면당신생을촉진시켜고혈당이초래되는것으로보고 (Goldberg, 1981) 되고있다. Kahn (1985) 은고혈당은 vascular oxidation 대사에이상을초래하여유리기를생성하고생성된유리기는 β-cell 의자동면역기능을파괴함으로써고혈당이정상화되지못하고그상태로유지된다고하였다. 혈청포도당농도와인슐린농도는 Table 4 와같다. 당뇨군에서정상식이군 (C) 에비해청국장 10% 식이군 (DC-10) 과청국장 20% 식이군 (DC-20) 은유의하게혈당강하효과를나타내었다 (p 0.05). 이와같은결과와 STZ 로유발된당뇨쥐에콩류를투여한결과혈당강하효과가나타났다는선행연구결과 ( 고진복, 1996; 김영숙, 2002) 를고려해볼때뽕청국장도혈당강하및항당뇨에효과가있는것으로사료된다. 혈청인슐린농도는정상군에비해당뇨대조군이약 42.4% 로낮았으며당뇨군내에서정상식이군과청국장식이군사이에는유의한차이가없었다. 3. 장기무게 간과신장의무게를측정한결과는 Table 5 와같다. 간과신장이체중에서차지하는상대적무게는정상군에비해당뇨군이유의하게증가하였으며 (p 0.01), 당뇨군내에서는정상식이군에비해청국장식이군에서낮게나타나는경향이있었으나통계적으로유의한차이는없었다. 당뇨유발시면역기능의저하를보이면서인슐린분비가저하되어당대사가정상적으로진행되지않아간내에지질이축적됨으로써간이비대
144 J. ENVIRON. TOXICOL. Vol. 21, No. 2 Table 5. Organ weights in diabetic rats fed the experimental diets for 3 weeks Organs Liver Kidney N C DC-1 DC-5 DC-10 DC-20 9.815±0.09 1) 9.215±0.69 9.138±0.34 9.895±0.52 10.318±1.09 9.728±0.40 3.095±0.01 2) 5.105±0.26 ## 4.965±0.41 ## 5.556±1.23 4.980±0.38 ## 4.970±0.23 ## 2.410±0.01 1) 2.755±0.20 2.745±0.20 2.715±0.24 3.018±0.42 2.843±0.26 0.759±0.01 2) 1.530±0.14 ## 1.489±0.13 ## 1.502±0.15 ## 1.451±0.09 ## 1.450±0.09 ## 1) Absolute organ weight: g. 2) Relative organ weight: g/100 g body weight. Values are mean±sd of 4 rats. ## Significantly different from the normal group by t-test (p 0.01). Table 6. Effect of Chunggugjang on hepatic SOD, CAT, GPX and GST activities in STZ-induced diabetic rats Items N C DC-1 DC-5 DC-10 DC-20 SOD 1) 125.96±51.86 36.39±2.08 # 35.68±7.84 # 25.11±11.20 # 30.48±8.27 # 18.24±2.79 ## ** CAT 2) 16.09±2.81 12.32±2.70 10.90±3.25 7.68±1.35 ## * 8.76±0.65 ## * 6.61±1.52 ## * GPX 3) 8.24±0.74 8.87±1.34 8.29±0.37 6.72±0.65* 7.33±0.73 6.02±0.58 # ** GST 4) 480.50±37.69 391.69±41.08 391.35±35.15 # 374.04±47.37 345.89±69.81 332.65±9.44 ## * 1) Unit: U(50% inhibition of autoxidation of hematoxylin) mg protein/min., 2) Unit: H 2O 2 nmole reduced/mg protein/min., 3) Unit: nmole NADPH oxidized/mg protein/min., 4) Unit: nmole 2, 4-dinitrobenzene-glutathione conjugate/mg protein/min. Values are mean±sd of 4 rats. The value with a sharp-note is significantly different from the normal group by t-test ( # : p 0.05, ## : p 0.01). The value with an asterisk is significantly different from the diabetes-normal group by t-test (*: p 0.05, **: p 0.01). 해지는것으로보고되어져있으며 (Grey et al., 1975; Dai et al., 1994), 이연구에서도당뇨군이정상군에비해간의상대적무게가약 65% 증가하였다. 당뇨쥐의신장은 pentose phosphate 경로에서포도당의유출과 RNA 및 DNA 의합성을증가시킴으로써신장의세포분열을촉진시켜신장이비대해지고 (Dai et al., 1994), 사구체여과율의증가와함께크기와용적이증가한다는선행연구결과 (Gallaher et al., 1993; 최승필등, 2004) 가있는데이연구에서도당뇨군이정상군에비해신장의상대적무게가약 102% 정도증가하였다. 4. 간조직의항산화효소활성변동 당뇨병상태에서생긴산화적스트레스는생체대사과정중에 oxygen free radical 을생성하여세포에상해를주며특히세포막의다가불포화지방산에작용하여지질과산화물을끊임없이생성하고이로인해세포의기능손상을초래한다 (Morel and Chisolm, 1989). 이러한 oxygen free radical 은 SOD 에의해 hydrogen peroxide (H 2O 2) 로전환되며이것은다시 CAT 및 GPX 에의해서물로전환되어해독화 (Deisseroth and Dounce, 1970) 되고 GST 도유해산소해독에관여하는것으로알려져있다. 유해산소해독계효소인 SOD, CAT, GPX 와 GST 를측정한결과는 Table 6 과같다. SOD 활성은정상군과비교하여당뇨대조군은유의한감소 (p 0.05) 를나타내었으며당뇨군내에서는정상식이군에비해청국장 20% 식이군에서유의하게낮게나타났다 (p 0.01). CAT 활성은정상군에비해당뇨대조군이 23.4% 감소하였으며당뇨군내에서는정상식이군에비해청국장 5%, 10%, 20% 식이군에서유의하게낮았다 (p 0.05). GPX 활성은당뇨군내에서는정상식이군에비해청국장 5% 식이군 (p 0.05) 과청국장 20% 식이군 (p 0.01) 이유의하게낮았다. GST 활성은정상군에비해당뇨대조군이 18.5% 감소하였으며당뇨군내에서정상식이군에비해청국장 20% 식이군이유의하게낮았다 (p
June 2006 Kim and Kim : Effects of Chunggugjang Powder in Diabetic Rats 145 0.05). SOD, CAT, GST 활성이정상군 (N) 에비해당뇨대조군 (C) 이낮게나타났는데이와같은결과는 STZ 로유도된당뇨쥐간조직중 SOD, CAT, GSH 활성의감소 (Saleh and David, 1987) 와간과신장조직중 SOD, CAT 활성의감소 (Saleh and David, 1987; Kesavulu et al., 2000) 를보고한선행연구결과와일치하며이는 STZ 로유도된당뇨쥐에서지질과산화물의증가로산화적손상이가속화되고이를방어하기위해생체내유해산소해독계효소들의활성이저하하는것으로해석된다. GPX 활성은 I 형당뇨모델의경우정상군과당뇨군에서유의적인차이는없었다고보고 (Lim and Kim, 1995) 된바있으며이연구에서도정상군 (N) 과비교하여당뇨대조군 (C) 에서약간높았으나유의적인차이는없었다. 당뇨군내에서는뽕청국장을많이첨가할수록유해산소해독계효소들의활성이더낮게나타나는추이를보였는데이는뽕청국장이 STZ 투여로생성된 oxygen free radical 등을포함한유해대사산물의빠른제거를위해유해산소해독계효소인 SOD, CAT, GPX 와 GST 를활발하게소모한결과로해석된다. 이연구결과를종합해볼때뽕청국장이활성산소나유해대사산물을제거하는데상당한역할을하는것으로사료되며향후실험기간을연장하여시간에따른효소활성의변동을추가적으로규명해보는것이필요하리라생각한다. 7.8% 감소한반면청국장식이군은함량 (1%, 5%, 10%, 20%) 에따라각각 9.9%, 24.3%, 15.2%, 13.9% 감소하는혈당강하효과를보였다. 3. 혈청포도당농도는당뇨군내에서정상식이군에비해청국장 10% 식이군과청국장 20% 식이군에서유의한혈당강하효과를보였다 (p 0.05). 4. 장기의상대적인중량비교에서간과신장의경우정상군에비해당뇨군이유의하게증가하였다 (p 0.01). 5. 항산화계효소인 SOD 활성은정상군과비교하여당뇨대조군은유의한감소 (p 0.05) 를나타내었으며당뇨군내에서는정상식이군에비해청국장 20% 식이군에서유의하게낮았다 (p 0.01). CAT 활성은정상군에비해당뇨대조군이 23.4% 감소하였으며당뇨군내에서는정상식이군에비해청국장 5%, 10%, 20% 식이군에서유의하게낮았다 (p 0.05). GPX 활성은당뇨군내에서는정상식이군에비해청국장 5% 식이군 (p 0.05) 과청국장 20% 식이군 (p 0.01) 이유의하게낮았다. GST 활성은정상군에비해당뇨대조군이 18.5% 감소하였으며당뇨군내에서정상식이군에비해청국장 20% 식이군이유의하게낮았다 (p 0.05). 이상의실험결과를통해뽕청국장은당뇨로인한체중저하를방지하고혈당강하효과를보여당대사를개선할뿐아니라항산화계에도영향을미침으로써당뇨합병증인산화적스트레스를억제하는효과가있는것으로사료된다 결 론 감사의글 뽕청국장이 streptozotocin (70 mg/kg B.W., i.p.) 으로유발된당뇨쥐에서혈당과항산화계에미치는영향을알아보고자청국장분말함량 (1%, 5%, 10%, 20%) 을달리하여 SD 랫드 (200~220g) 수컷에 3 주간실험식이를급여한실험에서다음과같은결과를얻었다. 1. 식이섭취량은정상군에비해당뇨군이약 2 배높았으며, 음수량은약 9 배높았다. 식이효율은당뇨대조군에서낮은수치를나타내었으나청국장 10% 와 20% 식이군의경우당뇨대조군에비해현저히높았다. 2. 혈중포도당농도는당뇨군에서정상식이군은 본연구는계명대학교대학원학생학술연구장학금지원에의해수행되었으며이에감사드립니다. 참고문헌 고진복. 대두와 magnesium 급여가당뇨쥐의혈당및지질대사에미치는영향, 한국식품영양과학회지 1996; 25: 963. 김영숙. 청국장이당뇨쥐의혈당및지질농도에미치는영향, 순천대학교대학원석사학위논문 2002; 34p. 정태석, 계상렬, 윤두석. Natto 및가열대두의영양학적고
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