Effects of green tea catechin on polymorphonuclear leukocyte 5'-lipoxygenase activity, leukotriene B4 synthesis, and renal damage in diabetic rats.
The purpose of this study was to investigate the effects of green tea catechin on polymorphonuclear leukocyte 5'-lipoxygenase activity, leukotriene B4 synthesis, and renal damage in diabetic rats. Male Sprague-Dawley rats weighing 100 +/- 10 g were randomly assigned to 1 normal group and 3 diabetic groups given a catechin-free diet (DM-0C group), 0.25% catechin diet (DM-0.25C group), or 0.5% catechin diet (DM-0.5C group), respectively. 5'-Lipoxygenase activity in the polymorphonuclear leukocytes significantly increased by 54% in the DM-0C group compared to the normal group, while the level in the DM-0.5C group remained the same as in the normal group. The leukotriene B4 content in the polymorphonuclear leukocytes increased 55% in the DM-0C group compared to the normal group, whereas the DM-0.25C and DM-0.5C groups exhibited the same level as the normal group. The superoxide radical content in the kidney microsomes increased 116% in the DM-0C group when compared to the normal group, yet decreased 29% in the DM-0.25C group and 50% in the DM-0.5C group compared to DM-0C group. The lipofuscin content was 197 and 136% higher in the DM-0C and DM-025C groups, respectively, than in the normal group, whereas the DM-0.5C group exhibited the same content as in the normal group. The carbonyl value increased 118% in the DM-0C group compared to the normal group, and the DM-0.25C and DM-0.5C groups were not significantly different from the DM-0C group. Accordingly, these results indicate that dietary catechin inhibited the generation of superoxide radicals, oxidized protein, and lipid peroxide in the kidney of streptozotocin-induced diabetic rats. Furthermore, green tea catechin supplementation in diabetic rats also appeared to inhibit the production of leukotriene B4 based on regulating the activity of 5'-lipoxygenase, thereby potentially reducing renal oxidative damage and inflammatory reactions.
Choi
Jeong-Hwa
JH
Division of Food Science, Jinju International University, Gyeongnam, Korea.
Chai
Young-Mi
YM
Joo
Gil-Jae
GJ
Rhee
In-Koo
IK
Lee
In-Seon
IS
Kim
Kwan-Ryu
KR
Choi
Myung-Sook
MS
Rhee
Soon-Jae
SJ
D000818:Animals; D002392:Catechin / Q000494:pharmacology*; D003921:Diabetes Mellitus, Experimental; D004305:Dose-Response Relationship, Drug; D007668:Kidney / Q000187:drug effects*; D007975:Leukotriene B4 / Q000096:biosynthesis*; D015227:Lipid Peroxidation / Q000187:drug effects; D008084:Lipoxygenase / Q000378:metabolism*; D008297:Male; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013481:Superoxides / Q000378:metabolism; D013662:Tea / Q000737:chemistry*
D013662:Tea; D013481:Superoxides; D007975:Leukotriene B4; D002392:Catechin; D008084:Lipoxygenase