title: Protective effects of epicatechin against the toxic effects of streptozotocin on rat pancreatic islets: in vivo and in vitro.
abstract: BACKGROUND
  Green tea catechins have diverse pharmacological effects such as anticarcinogenic and antioxidant activities.
  
  
  OBJECTIVE
  To study the protective effects of green tea (-)-epicatechin (EC) against the toxic effects of streptozotocin (STZ), a selective beta cell toxin, on pancreatic islets in vivo and in vitro.
  
  
  METHODS
  Rats were randomly divided into four groups: control, EC (30 mg/kg)-treated, STZ (60 mg/kg)-treated, and EC plus STZ (same doses; EC+STZ)-treated rats. EC was administered twice a day for 6 days, and a single injection of STZ was used. In EC+STZ-treated rats, EC was administered 6 hours prior to STZ since posttreatment with EC had no beneficial effects on fully developed diabetes in our unpublished study. Insulin and insulin mRNA were detected by immunohistochemical analysis and in situ hybridization, respectively, and physiologic parameters including blood glucose concentration were measured daily. Following isolation of the islets, insulin release, nitrite levels, and islet morphology were observed in the four groups: control, EC (0.8 mM)-treated, STZ (5 mM)-treated, and EC+STZ (same doses)-treated islets.
  
  
  RESULTS
  In EC+STZ-treated rats, hyperglycemia and weight loss were not observed and islet morphology was well preserved compared with STZ-treated rats. Compared with STZ treatment alone, insulin release was increased and nitrite production was decreased in EC+STZ-treated islets.
  
  
  CONCLUSIONS
  EC appears to be helpful in protecting pancreatic islets against exposure to STZ in both in vivo and in vitro systems.
authors.affiliation: Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Myung-Jun
authors.initials: MJ
authors.lastname: Kim
authors.forename: Gyeong Ryul
authors.initials: GR
authors.lastname: Ryu
authors.forename: Ji-Sung
authors.initials: JS
authors.lastname: Chung
authors.forename: Sang Soo
authors.initials: SS
authors.lastname: Sim
authors.forename: Do Sik
authors.initials: DS
authors.lastname: Min
authors.forename: Duck-Joo
authors.initials: DJ
authors.lastname: Rhie
authors.forename: Shin Hee
authors.initials: SH
authors.lastname: Yoon
authors.forename: Sang June
authors.initials: SJ
authors.lastname: Hahn
authors.forename: Myung-Suk
authors.initials: MS
authors.lastname: Kim
authors.forename: Yang-Hyeok
authors.initials: YH
authors.lastname: Jo
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002392:Catechin / Q000627:therapeutic use*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007328:Insulin / Q000096:biosynthesis; D008297:Male; D009573:Nitrites / Q000032:analysis; D010179:Pancreas / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D001786:Blood Glucose; D007328:Insulin; D009573:Nitrites; D012333:RNA, Messenger; D002392:Catechin