EFFECTS OF IRISIN ON THE REPRODUCTIVE SYSTEM OF OBESE FEMALE RATS INDUCED BY A HIGH-FAT DIET

Obesity is becoming more common all across the world, causing a variety of health problems, including reproductive disruption. Although the novel, exercise-induced hormone irisin may affect the hypothalamus-pituitary-gonadal axis and reproductive function control, its impact on obesity-induced damage to the female reproductive system is not fully known. Hence, this study aimed to investigate the potential effects of irisin on reproductive hormones and reproductive organs in female rats with obesity induced by a high-fat diet. Forty female rats were divided into four groups: control, irisin, obese, and obese+irisin (n = 10 in each group). After simulating a high-fat diet-induced obesity model (via 60% kcal fat for 12 weeks) in the obese and obese+irisin groups, irisin (100 ng/kg/day via mini-osmotic pumps for about 28 days) was administered subcutaneously to the irisin and obese+irisin groups. Results showed that subcutaneous irisin perfusion increased serum luteinizing hormone (LH), the LH to follicle-stimulating hormone (FSH) ratio (LH/FSH), and progesterone levels while decreasing the histopathological damage in the ovaries of obese rats. On the other hand, endogenous irisin serum concentrations were similar in lean female rats and obese female rats with reproductive disorders. These results suggest that irisin may affect the reproductive axis in obese female rats. An increase in serum LH levels, which trigger ovarian steroidogenesis, and reducing histopathological changes in ovarian tissue could contribute to this effect. Učinki irisina na reproduktivni sistem debelih samic podgan, povzročeni s prehrano z visoko vsebnostjo maščobIzvleček: Debelost je vse pogostejša po vsem svetu in povzroča različne zdravstvene težave, vključno z motnjami reprodukcije. Čeprav hormon irisin, ki se izloča med vadbo, lahko vpliva na hipotalamično-hipofizno-gonadno os in reproduktivno funkcijo, njegov vpliv na z debelostjo povezane poškodbe ženskega reproduktivnega sistema ni povsem znan. Zato je bil namen te študije raziskati morebitne učinke irisina na reproduktivne hormone in reproduktivne organe pri samicah podgan z debelostjo, povzročeno s prehrano z visoko vsebnostjo maščob. Štirideset samic podgan smo razdelili v štiri skupine: kontrola, irisin, debelost, debelost+irisin (n=10 v vsaki skupini). Po 12 tednih simulacije modela debelosti, povzročene s prehrano z visoko vsebnostjo maščob (60 % kcal maščobe), smo v skupinah debelost in debelostjo+irisin podganam podkožno dajali irisin (100 ng/kg/dan prek mini-osmotskih črpalk približno 28 dni). Podkožna aplikacija irisina je povečala serumski luteinizirajoči hormon (LH), razmerje med LH in folikle stimulirajočim hormonom (FSH) (LH/FSH) in raven progesterona, hkrati pa zmanjšala histopatološke poškodbe v jajčnikih debelih podgan. Vendar pa so bile koncentracije endogenega irisina v serumu vitkih in debelih podgan z reproduktivnimi motnjami podobne. Rezultati kažejo, da bi irisin lahko vplival na reproduktivno os debelih podgan. K temu učinku bi lahko prispevala povečanje serumske koncentracije LH, kar sproža steroidogenezo jajčnikov, ter zmanjšanje histopatoloških sprememb tkiva jajčnikov. Ključne besede: irisin; debelost; hormoni; jajčnik; apoptoza; reprodukcija pri samicah