Sains Malaysiana 42(11)(2013): 1591–1597

Membandingkan Kesan antara Fraksi-kaya Tokotrienol, Kalsium dan Estrogen

Terhadap Metabolisme Tulang Tikus Terovariektomi

(Comparing the Effects of Tocotrienol-rich Fraction, Calcium and Estrogen

on Bone Metabolism in Ovariectomized Rats)

Norliza Muhammad*, Surayya Razali, Ahmad Nazrun Shuid, Norazlina Mohamed

& Ima Nirwana Soelaiman

Jabatan Farmakologi, Fakulti Perubatan Universiti Kebangsaan Malaysia

Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia

Received: 27 October 2011/Accepted: 19 April 2013

ABSTRAK

Beberapa kajian sebelum ini menunjukkan penglibatan pengaruh tekanan pengoksidaan dalam patogenesis osteoporosis. Justeru agen antioksida berpotensi untuk digunakan bagi merawat dan mencegah osteoporosis. Dalam kajian ini, vitamin E sawit dalam bentuk fraksi-kaya tokotrienol ('tocotrienol-rich fraction', TRF) telah digunakan. Perbandingan dibuat antara rawatan TRF, kalsium dan estrogen terhadap parameter histomorfometri struktur tulang, kandungan kalsium dan kekuatan biomekanikal tulang pada tikus betina terovariektomi. Sebanyak 48 ekor tikus betina Sprague-Dawley dibahagikan kepada enam kumpulan, iaitu kawalan asas, sham, ovariektomi (OVX) dan kumpulan ovariektomi yang diberi rawatan samada kalsium, estrogen atau TRF. Rawatan diberikan secara paksaan oral selama dua bulan. Berdasarkan ujian histomorfometri tulang, tikus-tikus terovariektomi yang diberi kalsium, estrogen atau TRF menunjukkan peningkatan isi padu trabekular dan pengurangan jarak antara tulang trabekular secara signifikan berbanding dengan tikus kawalan ovariektomi. Disamping itu, rawatan estrogen dan TRF meningkatkan ketebalan trabekular secara signifikan berbanding dengan kumpulan OVX dan kalsium. Melalui ujian kandungan kalsium tulang, tikus yang diberi rawatan kalsium mempunyai aras kandungan kalsium dalam vertebra lumbar ke-empat yang lebih tinggi berbanding dengan kumpulan sham dan OVX. Kesimpulannya, rawatan kalsium, estrogen dan TRF berupaya memberikan kesan positif terhadap struktur tulang trabekular. TRF dan estrogen mampu mencegah penipisan tulang. Rawatan kalsium meningkatkan kandungan kalsium tulang, namun ia tidak berupaya untuk mencegah penipisan tulang.

Kata kunci: Estrogen; histomorfometri struktur tulang; mineral tulang; osteoporosis; tokotrienol; vitamin E

ABSTRACT

Previous studies showed the role of oxidative stress in the pathogenesis of osteoporosis. Thus antioxidant agents have the potential to be used in the treatment and prevention of osteoporosis. In this study, vitamin E in the form of tocotrienol-rich fraction (TRF) was used. Comparison of the effects of treatments was made among TRF, calcium and estrogen. A total of 48 female Sprague-Dawley rats were divided into six groups: baseline, sham-operated, ovariectomized control and ovariectomized given calcium, estrogen or TRF. The treatment agents were administered via oral gavage for two months. Bone histomorphometry showed that treatment with either calcium, estrogen or tocotrienol was able to increase the trabecular volume and reduce the distance between the trabecular bone significantly compared with the ovariectomy control group. Treatment with either estrogen or tocotrienol showed significant increase in the thickness of the trabecular compared with the control group. Based on the calcium content test, supplementation with calcium increased the levels of calcium content in the fourth vertebral lumbar significantly compared with the sham and ovariectomy group. In conclusion, calcium, estrogen and tocotrienol had positive effects on the trabecular bone. However, tocotrienol was more superior to calcium or estrogen in preventing bone loss in postmenopausal osteoporosis. Tocotrienol prevented bone thinning and loss of volume without the side effects as estrogen. Although calcium can improve the bone calcium content, still, it was unable to prevent bone thinning.

Keywords: Bone mineral content; estrogen; osteoporosis; structural histomorphometry; tocotrienol; vitamin E

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*Corresponding author; email: norliza_ssp@yahoo. com