Effects of Palm Tocotrienols on Oxidative Stress and Bone Strength in Ovariectomised Rats
Effects of tocotrienols on ovariectomised-rat bone
Abstract
Oxidative stress has been associated with postmenopausal osteoporosis which predisposes to risk of fracture. Palm tocotrienol is a potent antioxidant and has the potential to be used for treatment of post-menopausal osteoporosis. The aim of the study is to determine if palm tocotrienol supplementation could alleviate oxidative stress in ovariectomised rat model and improve its bone strength. The rats were divided into four groups: (i) sham-operated group (SHAM) (ii) ovariectomised-control group (OVX) (iii) ovariectomised and given 60mg/kg α-tocopherol by oral gavage (OVX + ATF) (iv) ovariectomised and given 60mg/kg palm tocotrienols by oral gavage (OVX + PTT). After eight weeks of treatment, blood samples were taken to measure oxidative status (MDA, SOD and GPX) while the femurs were biomechanically tested for strength and resistance to fracture. Ovariectomy was shown to induce oxidative stress as shown by the raised MDA levels and reduced GPX activity. Palm tocotrienols seemed to offer protection against the ovariectomy-induced oxidative stress as shown by the suppression of MDA levels and raised GPX and SOD activities in the OVX+PTT group. In comparison, α-tocopherol was only able to raise the SOD but not as high as palm tocotrienols. The biomechanical tests have shown that ovariectomy has not affected the bone strength significantly after eight weeks. Palm tocotrienols supplementation for eight weeks was effective in preventing oxidative stress in a post-menopausal rat.
Keywords :
biomechanical,
bone histomorphometry,
osteoporosis,
ovariectomised-rats,
vitamin E,
Abstrak
Stres oksidatif dikaitkan dengan osteoporosis pos-menopaus yang meningkatkan risiko patah tulang. Tokotrienol sawit ialah antioksidan yang poten dan berpotensi untuk digunakan bagi merawat osteoporosis pos-menopaus. Tujuan kajian ialah untuk menentukan samada suplementasi tokotrienol sawit boleh mengurangkan stress oksidatif dan meningkatkan kekuatan tulang pada model tikus terovariektomi. Tikus dibahagikan kepada empat kumpulan : (i) bedah sham (SHAM) (ii) kawalan ovariektomi (OVX) (iii) ovariektomi dan diberi 60mg/kg α-tokoferol melalui gavaj oral (OVX+ATF) (iv) ovariektomi dan diberi 60mg/kg tokotrienol sawit melalui gavaj oral (OVX+PTT). Selepas rawatan selama lapan bulan, sampel darah diambil untuk mengukur status oksidatif (MDA, SOD dan GPX) sementara tulang femur diuji kekuatan dan resistan biomekanikal terhadap kepatahan. Ovariektomi menyebabkan stres oksidatif seperti yang ditunjukkan dengan peningkatan aras MDA dan penurunan aras aktiviti GPX. Tokotrienol sawit menunjukkan perlindungan terhadap stres oksidatif aruhan ovariektomi seperti yang ditunjukkan dengan penurunan aras MDA dan peningkatan aktiviti GPX dan SOD pada kumpulan OVX+PTT. Apabila dibandingkan, α-tokoferol hanya berupaya meningkatkan SOD tetapi tidak setinggi tokotrienol sawit. Ujian biomekanikal menunjukkan bahawa ovariektomi tidak memberi kesan signifikan kepada kekuatan tulang selepas rawatan selama lapan minggu. Suplementasi tokotrienol sawit selama lapan minggu berkesan untuk mencegah stres oksidatif pada tikus pos-menopaus.
Kata Kunci :
biomekanikal,
histomorfometri tulang,
osteoporosis,
tikus terovariektomi,
vitmain E,
Correspondance Address
Professor Dr Ima Nirwana Soelaiman. Department of Pharmacology, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur. Tel: 03-92897281 / 5514 Fax; 603- 26938205
E-mail: imasoel@medic.ukm.my
