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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
Diserahkan: 27 Oktober 2011/Diterima: 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.
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Bone mineral content; estrogen; osteoporosis; structural histomorphometry;
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*Pengarang untuk surat-menyurat; email: norliza_ssp@yahoo. com
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