Osteoporosis dikaitkan dengan radikal bebas dan tekanan oksidatif. Kandungan polifenol yang tinggi dalam minyak
kelapa dara (VCO) yang bertindak sebagai antioksidan mampu menghalang tekanan oksidatif seterusnya mencegah
osteoporosis. Uji kaji in vitro ini dijalankan untuk mengkaji mekanisme kesan perlindungan polifenol ekstrak daripada
VCO (PF) ke atas sel selanjar pre-osteoblas mencit (MC3T3-E1) teraruh tekanan oksidatif. Untuk mengkaji viabiliti
kesan perlindungan polifenol terhadap MC3T3-E1 daripada toksisiti hidrogen peroksida (H2
O2
), sel MC3T3-E1 dirawat
dengan beberapa dos polifenol selama 24 jam selepas dieram dengan 250 µM (IC50) H2
O2
selama 1 jam. Mekanisme
perlindungan dikaji dengan mengukur aras malondialdehid (MDA) serta aktiviti enzim antioksidan iaitu superoksida
dismutase (SOD), glutation peroksidase (GPx) dan katalase (CAT). Keputusan kajian menunjukkan bahawa kepekatan
perencatan median (IC50) H2
O2
pada 1 jam adalah 250 µM. Ujian viabiliti sel mendapati kesemua dos polifenol dapat
melindungi sel MC3T3-E1 daripada toksisiti H2
O2
. Dos 1 dan 0.01 µM polifenol dapat meningkatkan aras GPx dan CAT,
manakala dos 0.01 dan 0.0001 µM dapat meningkatkan aras SOD. Sementara itu, hanya dos 0.01 dan 0.001 µM sahaja
yang dapat menghalang peningkatan aras MDA. Kesimpulan yang dapat dibuat di dalam kajian ini adalah polifenol
daripada minyak kelapa dara mencegah lipid peroksida pada sel MC3T3-E1 yang telah diaruh dengan H2
O2
dengan
meningkatkan aktiviti enzim antioksidan.
Postmenopausal osteoporosis is one of the main health problems in aging women. It was due to several factors including oxidative stress, which can be controlled through intake of antioxidants from food sources. Virgin coconut oil (VCO) is one of the natural product rich in antioxidants and has been proven to protect osteoporotic bone. This study was conducted to gain in-depth understanding on virgin coconut oil’s activity on osteoporosis at molecular level. Thirty two female Sprague-Dawley rats were divided into four groups, namely Sham operated group, ovariectomized control group (Ovx+Ctrl), ovariectomized with VCO treatment (Ovx+VCO), and ovariectomized with estrogen treatment (Ovx+E). All treatments were administered orally for ten weeks. Bone samples were obtained to examine changes on expression of superoxide dismutase (SOD), glutathione peroxidase (GPX), osteocalcin and runt-related transcription factor 2 (Runx2) genes. The results indicated that rats receiving VCO treatment had experienced significant increments in SOD, GPX and osteocalcin gene expressions compared to the ovariectomized control group, besides the gene expressions of Runx2 which also showed an increment pattern. In conclusion, VCO helps to protect bone in osteoporotic rat model by increasing the expressions of antioxidant genes and genes which increase the osteoblast acitivities.
Keywords: Osteoporosis; ovariectomized rat model; postmenopausal; virgin coconut oil
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.
Vitamin E is beneficial in restoring bone histomorphometric parameters in nicotine-treated rats. This study determined the effectiveness of 3 forms of vitamin E in restoring bone metabolism in nicotine-treated rats.
Quantitative ultrasound (QUS) is a relatively easy, reliable, and safe method for bone status assessment, but reference data for Asian males remain scarce. Our study aimed to determine the values for one QUS parameter, the speed of sound (SOS) at the calcaneus, in Malaysian Chinese men and to determine the association between the SOS and several demographic characteristics, such as age, weight, height, and body mass index. Three hundred forty-eight Malaysian Chinese men aged 40 yr and older were recruited, and their calcaneal QUS value was determined using the CM-200 densitometer (Furuno Electric, Nishinomiya City, Japan). The results indicated a significant correlation between SOS and age, and multiple stepwise regression analysis indicated that age and height were important predictors of SOS. A significant reduction in SOS value was observed when men 60 yr and older were compared with men aged 40-49 yr. Compared with the reference data for Japanese males, Chinese men in Malaysia showed higher SOS values across all the age groups studied. In conclusion, there is an age-related decrease in SOS values in Malaysian Chinese men, and the SOS values established in this study can be used as a reference for future studies.