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.
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.
The prevalence of osteoporosis is increasing in Asian countries. Optimum calcium intake and vitamin D level are
important to prevent osteoporosis. The attitude of the society towards calcium food sources and supplements, as well
as sun exposure, influence their bone health practices. This review aimed to summarize the current literature on the
attitude of Asians on calcium and vitamin D rich foods and supplements to understand the barriers among the Asians
in achieving adequate calcium intake and vitamin D level. Studies showed that most Asians have a negative attitude
towards calcium-rich foods, mainly dairy products due to lactose intolerance, aversion to the taste of dairy products or
the absence of motivation. Although they took supplements to fill the gap in their diet, they were not aware of the daily
recommended intake of calcium. Besides, the majority of them have a negative attitude towards sun exposure due to the
fear of getting skin cancer or tanning. As a conclusion, most of Asians are still not aware of the importance of calcium
and vitamin D for their health and their negative attitude must be corrected to prevent the rise of osteoporosis.
This study was conducted to determine the effectiveness of three forms of vitamin E supplements following nicotine treatment on bone histomorphometric parameters in an adult male rat model. Rats were divided into seven groups: baseline (B, killed without treatment), control (C, normal saline for 4 months), nicotine (N, nicotine for 2 months), nicotine cessation (NC), tocotrienol-enhanced fraction (TEF), gamma-tocotrienol (GTT), and alpha-tocopherol (ATF). Treatments for the NC, TEF, GTT, and ATF groups were performed in two phases. For the first 2 months they were given nicotine (7 mg/kg), and for the following 2 months nicotine administration was stopped and treatments with respective vitamin E preparations (60 mg/kg) were commenced except for the NC group, which was allowed to recover without treatment. Rats in the N and NC groups had lower trabecular bone volume, mineral appositional rate (MAR), and bone formation rate (BFR/BS) and higher single labeled surface and osteoclast surface compared to the C group. Vitamin E treatment reversed these nicotine effects. Both the TEF and GTT groups, but not the ATF group, had a significantly higher trabecular thickness but lower eroded surface (ES/BS) than the C group. The tocotrienol-treated groups had lower ES/BS than the ATF group. The GTT group showed a significantly higher MAR and BFR/BS than the TEF and ATF groups. In conclusion, nicotine induced significant bone loss, while vitamin E supplements not only reversed the effects but also stimulated bone formation significantly above baseline values. Tocotrienol was shown to be slightly superior compared to tocopherol. Thus, vitamin E, especially GTT, may have therapeutic potential to repair bone damage caused by chronic smoking.
In this study the effects of vitamin E deficiency and supplementation on bone calcification were determined using 4-month-old female Sprague-Dawley rats. The rats weighed between 180 and 200 g. The study was divided in three parts. In experiment I the rats were given normal rat chow (RC, control group), a vitamin E deficient (VED) diet or a 50% vitamin E deficient (50%VED) diet. In experiment 2 the rats were given VED supplemented with 30 mg/kg palm vitamin E (PVE30), 60 mg/kg palm vitamin E (PVE60) or 30 mg/kg pure alpha-tocopherol (ATF). In experiment 3 the rats were fed RC and given the same supplements as in experiment 2. The treatment lasted 8 months. Vitamin E derived from palm oil contained a mixture of ATF and tocotrienols. Rats on the VED and 50%VED diets had lower bone calcium content in the left femur compared to the RC group (91.6 +/- 13.3 mg and 118.3 +/- 26.0 mg cf 165.7 +/- 15.2 mg; P < 0.05) and L5 vertebra (28.3 +/- 4.0 mg and 39.5 +/- 6.2 mg compared with 51.4 +/- 5.8 mg; P < 0.05). Supplementing the VED group with PVE60 improved bone calcification in the left femur (133.6 +/- 5.0 mg compared with 91.6 +/- 13.3 mg; P < 0.05) and L5 vertebra (41.3 +/- 3.3 mg compared with 28.3 +/- 4.0 mg; P < 0.05) while supplementation with PVE30 improved bone calcium content in the L5 vertebra (35.6 +/- 3.1 mg compared with 28.3 +/- 4.0 mg; P < 0.05). However, supplementation with ATF did not change the lumbar and femoral bone calcium content compared to the VED group. Supplementing the RC group with PVE30, PVE60 or ATF did not cause any significant changes in bone calcium content. In conclusion, vitamin E deficiency impaired bone calcification. Supplementation with the higher dose of palm vitamin E improved bone calcium content, but supplementation with pure ATF alone did not. This effect may be attributed to the tocotrienol content of palm vitamin E. Therefore, tocotrienols play an important role in bone calcification.
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.