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    Effect of white tea consumption on serum leptin, TNF-α and UCP1 gene expression in ovariectomized rats
    (John Libbey, 2021) Saral, Sinan; Saydam, Faruk; Dokumacıoğlu, Eda; Atak, Mehtap; Tümkaya, Levent; Uydu, Hüseyin Avni
    Background: Obesity and dyslipidemia due to estrogen deficiency are among the important health problems in menopausal women. Increasing evidence reports the anti-obesity and anti-hyperlipidemic properties of tea polyphenols. However, the effect of white tea (WT) with high polyphenol content on overweight and lipid profile is uncertain. Here, we aimed to examine the effects of long-term WT consumption on serum leptin, tumor necrosis factor- alpha (TNF-?) and uncoupling protein 1 (UCP1) mRNA gene expression in ovariectomized (OVX) rats. Methods: Adult rats were divided into four groups (n = 8): (i) sham, (ii) OVX, (iii) WT and (iv) OVX + WT. WT was given at a dose of 0.5% w/v for 12 weeks. In the study, body weight, serum leptin, TNF, estradiol (E2) levels, lipid profile and UCP1 mRNA gene expression in brown adipose tissue (BAT) were evaluated. Results: There was a significant increase in body weight of OVX rats, which was decreased following WT consumption. While leptin and E2 levels decreased in the OVX group, TNF levels increased. There was no difference between the NF-?B levels of the groups. In addition, BAT UCP1 mRNA expression was significantly decreased in OVX groups, while WT treatment stimulated UCP1 activity. Conclusion: We explain the stimulatory effect of WT on weight loss mainly by the induction of UCP1 gene-mediated thermogenesis and suppression of inflammation. Therefore, we suggest that prolonged WT consumption may have beneficial effects in limiting excess weight gain caused by estrogen deficiency.
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    Öğe
    White tea reduced bone loss by suppressing the TRAP/CTX pathway in ovariectomy-induced osteoporosis model rats
    (NLM (Medline), 2020) Yıldırım, Murat; Mercantepe, Tolga; İskender, Hatice; Tümkaya, Levent; Atak, Mehtap; Taşçı, Filiz
    Osteoporosis is an important skeletal disease characterized by bone weakness and high risk of fracture in postmenopausal women. Tea consumption is known to play an important role in the prevention or alleviation of osteoporosis. However, the therapeutic effects of aqueous extracts of white tea (WT) have not been evaluated in osteoporosis rat models. The aim of this study was to investigate the potential anti-osteoporotic role of WT in ovariectomized (OVX) rats. WT was given orally at 0.5% w/v doses for 12 weeks in OVX rats. Biochemical parameters in blood samples, bone tartrate-resistant acid phosphatase (TRAP), C-terminal telopeptide of type 1 collagen (CTX) and estradiol levels were evaluated. Bone mineral density and bone mineral content values were measured in the left femur. In addition to histopathological examination, osteolcalcin, osteopontin and TUNEL levels were determined. OVX group data demonstrated that bone loss occurred by thinning of the metaphyseal growth plates of the femur. Similarly, the levels of TRAP and CTX, markers of osteoclastic activity, were found to be high concurrently with a decrease in femoral bone mineral density. In addition, increased osteolcalcin and osteopontin levels were present in the metaphyseal growth zones. On the other hand, while TRAP and CTX levels were suppressed in the OVX-WT group, bone mineral content increased. In ad­dition, TUNEL, osteocalcin and osteopontin positivity decreased in the right femoral metaphysis growth zones, proliferating zone and resting zone cells. These results showed that chronic WT consumption has a protective effect by reducing bone resorption in OVX-induced osteoporotic rats.