Green tea impedes dyslipidemia, lipid peroxidation, protein glycation and ameliorates Ca2+ -ATPase and Na+/K+ -ATPase activity in the heart of streptozotocin-diabetic rats.
Diabetes-induced hyperlipidemia, oxidative stress and protein glycation impair cellular calcium and sodium homeostasis associated with abnormal membrane-bound enzyme activities resulting in cardiac dysfunction in diabetes. To explore the cardioprotective mechanism of green tea in diabetes, we measured the changes in the levels of calcium, sodium, potassium and the activities of Na+/K+ -ATPase and Ca2+ -ATPase in green tea treated diabetic rat hearts. The effect of green tea on triglycerides, lipid peroxidation and protein glycation in diabetic heart were also measured to elucidate the underlying mechanisms. Diabetes was induced by streptozotocin (STZ, 60 mg/kg i.p.). Six weeks after the induction of diabetes, some of the diabetic rats were treated orally with green tea extract (GTE) (300 mg/kg/day) for 4 weeks. GTE produced reduction in blood glucose and lowered the levels of lipid peroxides, triglycerides and extent of protein glycation in the heart of diabetic rats. GTE blunted the rise in cardiac [Ca2+] and [Na+] whereas increased the activities of Ca2+ -ATPase and Na+/K+ -ATPase in diabetic rats. In conclusion, the data provide support to the therapeutic effect of GTE and suggest that a possible mechanism of action may be associated with the attenuation of the rise in [Ca2+] and [Na+] by ameliorating Ca2+ -ATPase and Na+/K+ -ATPase activities.
Babu
Pon Velayutham Anandh
PV
Department of Biochemistry, University of Madras, Guindy Campus, Chennai 600025, Tamilnadu, India.
Sabitha
Kuruvimalai Ekambaram
KE
Shyamaladevi
Chennam Srinivasulu
CS
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D028241:Camellia sinensis / Q000737:chemistry*; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy* / Q000378:metabolism; D004326:Drinking / Q000187:drug effects; D050171:Dyslipidemias / Q000188:drug therapy* / Q000378:metabolism; D004435:Eating / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D006031:Glycosylation / Q000187:drug effects; D006321:Heart / Q000187:drug effects* / Q000254:growth & development; D015227:Lipid Peroxidation / Q000187:drug effects; D008054:Lipid Peroxides / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism; D009929:Organ Size / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use; D011188:Potassium / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism
D001786:Blood Glucose; D008054:Lipid Peroxides; D010936:Plant Extracts; D014280:Triglycerides; D012964:Sodium; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase; D005978:Glutathione; D011188:Potassium; D002118:Calcium