Gonca OZAN, Elif ERDEM, Enver OZAN, Nalan KAYA, Osman Fatih YILMAZ

Yüksek Fruktoz Diyeti ile Metabolik Sendrom Oluşturulan Ratların Testis Dokusunda Ghrelin Dağılımına Oleuropeinin Etkisi

Bu çalışmada yüksek fruktoz diyeti ile deneysel olarak oluşturulan metabolik sendrom modelinin rattestis dokusuna etkileri ve ratların testis dokusundaki ghrelin ekspresyonunda oleuropeinuygulanmasının meydana getireceği değişimlerin, biyokimyasal ve immünohistokimyasalyöntemlerle belirlenmesi amaçlandı.Sekiz haftalık 32 adet erkek Sprague-Dawley cinsi rat rastgele Kontrol, Metabolik sendrom,Oleuropein, Metabolik sendrom+Oleuropein olmak üzere 4 gruba ayrıldı. Metabolik sendromoluşturmak amacıyla %20 fruktoz içeren içme suyu kullanıldı ve Oleuropein 10 mg/kg/gün oralolarak uygulandı. 60 günlük deney sonunda ratlar dekapite edilerek kan ve testis doku örneklerialındı. Serum glukoz, insülin ve trigliserid düzeyleri ölçüldü. Testis dokularında streptavidin-biyotinperoksidazyöntemi ile ghrelin immünreaktivitesi belirlendi. Ayrıca, testis dokularındamalondialdehit (MDA) düzeyleri ve katalaz aktivitesi spektrofotometrik yöntemlerle ölçüldü.Fruktoz uygulamasının; serum trigliserid, insülin düzeyleri ve insülin direncinde anlamlı bir artışyaptığı saptandı. Yüksek fruktoz diyeti ile deneysel olarak metabolik sendrom oluşturulan ratlarıntestis dokusunda ghrelin ekspresyonunun azaldığı, oleuropein uygulanmasının ise testisdokusunda azalmış ghrelin ekspresyonunu arttırdığı belirlendi. Metabolik sendrom grubunda testisdokusu MDA düzeylerinin arttığı ve katalaz aktivitesinin azaldığı belirlendi. Diğer taraftan metaboliksendrom+oleuropein grubunda, metabolik sendrom grubuna göre testis dokusunda MDAdüzeylerinin azaldığı, katalaz aktivitesinin ise arttığı tespit edildi.Yüksek fruktoz diyeti ile oluşturulan metabolik sendrom modelinde, testis dokusunda oksidatifstresin arttığı saptandı. Metabolik sendromda bu doz ve sürede oleuropein uygulamasının, aşırıfruktoz tüketiminin neden olduğu olumsuz etkilere karşı testis dokusunda koruma sağladığı veantioksidan bir rol oynadığı belirlendi.

The Effect of Oleuropein on Ghrelin Expression in Rat Testes with FructoseInduced Metabolic Syndrome

We aimed to investigate the effects of oleuropein administration on ghrelin expression in rat testestissues with fructose-induced metabolic syndrome by immunohistochemical and biochemicalmethods.Thirty-two male adult (8 week aged) Sprague-Dawley rats were randomly divided into four groups(n=8); Control, Meabolic syndrome, Oleuropein, Metabolic syndrome plus Oleuropein. Metabolicsyndrome was induced by fructose solution 20% in drinking water, and oleuropein wasadministered at the dose of 10 mg/kg daily by oral gavage. After the experimental period of 60days, the rats were decapitated, testes tissues and blood samples were taken. Serum glucose,insulin and triglyceride levels were measured. The testes samples were immunehistochemicallystained using avidin-biotin-peroxidase method for the determination of ghrelin immunoreactivity.Also testes tissue malondialdehyde (MDA) levels and catalase activity were determinedspectrofotometrically.Fructose consumption significantly increased serum triglyceride, insulin levels and insulinresistance. Ghrelin immunoreactivity in rat testes tissues with fructose-induced metabolic syndromewas determined as low. Oleuropein administration increased testes ghrelin levels. In comparisonwith control group, MDA levels increased and CAT activities decreased in metabolic syndromegroup. On the other hand MDA levels were diminished and Cat activities were elevated in fructoseplus oleuropein group compared to the metabolic syndrome group.These results indicate that metabolic syndrome increases oxidative stress in testicular tissue. It canbe suggested that at that the dose and time of oleuropein administration can play a role as anantioxidant and protect the testes from the effects of high fructose induced metabolic syndrome.

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1. Reaven GM. Banting Lecture 1988. Role of insulin resistance in human disease. Diabetes 1988; 37: 1595- 1607.
2. Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults: Executive summary of the Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). JAMA 2001; 285: 2486-2497.
3. Goulis DG, Tarlatzis BC. Metabolic syndrome and reproduction: I. Testicular function. Gynecol Endocrinol 2008; 24: 33-39.
4. Kasturi SS, Tannir J, Brannigan RE. The metabolic syndrome and male infertility. J Androl 2008; 29: 251-259.
5. Kojima M, Hosoda H, Date Y, et al. Ghrelin is a growth hormone-releasing acylated peptide from stomach. Nature 1999; 402: 656-659.
6. Aydin S, Ozkan Y, Caylak E, Aydin S. Ghrelin and its biochemical functions. Turkiye Klinikleri J Med Sci 2006; 26: 272-283.
7. Wren AM, Seal LJ, Cohen MA, et al. Ghrelin enhances appetite and increases food intake in humans. Journal of Clinical Endocrinology and Metabolism 2001; 86: 5992.
8. Gauna C, Delhanty PJ, Hofland LJ, et al. Ghrelin stimulates, whereas des-octanoyl ghrelin inhibits, glucose output by primary hepatocytes. Journal of Clinical Endocrinology and Metabolism 2005; 90: 1055-1060.
9. Gnanapavan S, Kola B, Bustin SA, et al. The tissue distribution of the mRNA of ghrelin and subtypes of its receptor, GHS-R, in humans. Journal of Clinical Endocrinology and Metabolism 2002; 87: 2988-2991.
10. Owen RW, Giacosa A, Hull WE, et al. Olive oil consumption and health: The possible role of antioxidants. Lancet Onco 2000; 21: 107-112.
11. Sanchez-Lozada LG, Tapia E, Jimenez A, et al. Fructose - induced metabolic syndrome is associated with glomerular hypertension and renal microvascular damage in rats. Am J Physiol Renal Physiol 2007; 292: F423-429.
12. Placer ZA, Cushman LL, Johnson BC. Estimation of product of lipid peroxidation (malonyldialdehyde) in biochemical systems. Anal Biochem 1966; 16: 359-364.
13. Aebi H. Catalase in vitro. Method Enzymol 1984; 105: 121- 126.
14. Lowry OH, Rosenbrough NJ, Farr AL, Randall RJ. Protein measurements with the folin phenol reagent. J Biol Chem 1951; 193: 265-275.
15. Monteiro R, Andazevedo I. Chronic inflammation in obesity and the metabolic syndrome. J Mediators of Inflammation 2010; 14: 289645.
16. Elliott SS, Keim NL, Stern JS, Teff K, Andhavel PJ. Fructose, weight gain, and the insulin resistance syndrome. The American Journal of Clinical Nutrition 2002; 76: 911- 922.
17. Hwang IS, Ho H, Hoffman BB, Reaven GM. Fructoseinduced insulin resistance and hypertension in rats. Hypertension 1987; 10: 512-516.
18. Turner T, Lysiak J. Oxidative stress: A common factor in testicular dysfunction. J Androl 2008; 29: 488-498.
19. Kim JH, Kim HJ, Noh HS, et al. Suppression by ethanol of male reproductive activity. Brain Research 2003; 989: 91- 98.
20. Shrilatha B. Early oxidative stress in testis and epididymal sperm in streptozotocin-induced diabetic mice: Its progression and genotoxic consequences. Reprod Toxicol 2007; 23: 578-587.
21. Doreswamy K, Shrilatha B, Rajeshkumar T. Nickelinduced oxidative stress in testis of mice: Evidence of DNA damage and genotoxic effects. J Androl 2004; 25: 996- 1003.
22. Menéndeza E, Valdésb S, Botasa P. Glucose tolerance and plasma testosterone concentrations in men. Endocrinol Nutr 2011; 58: 3-8.
23. Laaksonen D, Niskanen L, Punnonen K. Testosterone and sex hormone-binding globulin predict the metabolic syndrome and diabetes in middle-aged men. Diabetes Care 2004; 27: 1036-1041.
24. Gaytan F, Barreiro ML, Caminos JE, et al. Expression of ghrelin and its functional receptor, the type 1a growth hormone secretagogue receptor, in normal human testis and testicular tumors. Journal of Clinical Endocrinology and Metabolism 2004; 89: 400-409.
25. Ukkola O, Pöykköand SM, Kesaniemi YA. Low plasma ghrelin concentration is an indicator of the metabolic syndrome. Journal of Clinical Endocrinology and Metabolism 2005; 90: 6448-6453.
26. Ukkola O. Ghrelin and metabolic disorders. Current Protein and Peptide Science 2009; 10: 2-7.
27. Barazzoni R, Zanetti M, Ferreira C, et al. Relationships between desacylated and acylated ghrelin and insulin sensitivity in the metabolic syndrome. Journal of Clinical Endocrinology and Metabolism 2007; 92: 3935-3940.
28. Mclaughlin T, Abbasi F, Lamendola C, Frayo RS, Cummings DE. Plasma ghrelin concentrations are decreased in insulin-resistant obese adults relative to equally obese insulin-sensitive controls. Journal of Clinical Endocrinology and Metabolism 2004; 89: 1630-1635.
29. Schofl C, Horn R, Schill T, et al. Circulating ghrelin levels in patients with polycystic ovary syndrome. Journal of Clinical Endocrinology and Metabolism 2002; 87: 4607-4610.
30. Reinehr T, Roth CL, Alexy U, et al. Ghrelin levels before and after reduction of overweight due to a low-fat highcarbohydrate diet in obese children and adolescents. International Journal of Obesity 2005; 29: 362-368.
31. Broglio F, Gottero C, Prodam F, et al. Ghrelin secretion is inhibited by glucose load and insulin-induced hypoglycaemia but unaffected by glucagon and arginine in humans. Clinical endocrinology 2004; 61: 503-509.
32. Tuck KL, Freeman MP, Hayball PJ, Stretch GL, Stupans I. The in vivo fate of hydroxytyrosol and tyrosol, antioxidant phenolic constituents of olive oil, after intravenous and oral dosing of labeled compounds torats. J Nutr 2001; 131: 1993-1996.
33. Visioli F, Bellomo G, Galli C. Free radical-scavenging properties of olive oil polyphenols. Biochemical and Biophysical Research Communications 1998; 247: 60-64.
34. Alirezaei M, Kheradmand A, Heydari R, et al. Oleuropein protects against ethanol-induced oxidative stress and modulates sperm quality in the rat testis. Mediterranean Journal of Nutrition and Metabolism 2012; 5: 205-211.