Androgen ablation therapy using gonadotropin-releasing hormone agonists is reported to be associated with metabolic abnormalities. Annatto tocotrienol (AnTT) is reported to reduce the expression of genes related to adipogenesis but the mechanism remains elusive. This study sought to determine the effects of annatto tocotrienol on body composition (lean and fat mass), serum adiponectin, leptin, and glucose levels in male rats treated with buserelin, a testosterone ablation agent. Three-month-old male Sprague Dawley rats (n=32) were randomly divided into four groups. The normal control (n=8) was given corn oil orally daily and normal saline subcutaneously daily. The remaining groups were injected with buserelin subcutaneously (75µg/kg/day). The buserelin group (n=8) was given corn oil orally, while the treatment groups were supplemented orally with AnTT at 60 or 100 mg/kg (n = 8/group). After treatment of 12 weeks, rats were euthanized. Dual-energy x-ray absorptiometry was performed to determine the lean and fat mass of the rats. Blood was collected for the evaluation of adiponectin, leptin and glucose levels. After 12 weeks, the lean mass, fat mass, adiponectin and leptin levels for all groups increased significantly compared to their respective baseline levels irrespective of their treatment (P<0.05). All groups, except rats receiving AnTT at 60 mg/kg, experienced a significant increase in glucose level after 3 months (P<0.05). Androgen ablation and AnTT do not influence body composition, adiponectin and leptin levels in male rats. However, annatto tocotrienol at 60 mg/kg may improve glucose metabolism.

Bone histomorphometric measurements are required to understand the efficacy of treatment on bone remodelling. Previous studies used the Weibel technique as a quantitative stereological method to determine bone cellular and dynamic changes. However, there was no description on how this technique was applied. This studyaimed to provide a full picture about the utilization of the Weibel technique to measure static and dynamic bone histomorphometric indices. Technical expertise, processing of bone samples, randomization of the trabecular sections and an adequate number of analysed images for each section are required to achieve reliable results with a low possibility of errors.
Bone and Bones

Oxidative stress has been associated with postmenopausal osteoporosis which pre-disposes to risk of fracture. Palm tocotrienol is a potent antioxidant and has the poten-tial 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 af-fected the bone strength significantly after eight weeks. Palm tocotrienols supplemen-tation for eight weeks was effective in preventing oxidative stress in a post-meno-pausal rat.

The use of repeatedly heated frying oils and intake of high cholesterol diet have been linked to bone damage. The aim of this study is to determine the combined effects of taking repeatedly heated frying oils (palm or soy oil) and high cholesterol diet on the dynamic histomorphometric parameters of bone. Ovariectomised rats were used as animal model of post-menopausal osteoporosis. After six months of treatment, Double-labeled Surface (dLS/BS), Mineralising surface (MS/BS) and Bone Formation Rate (BFR/BS) of ovariectomised rats (OvxC) were significantly reduced compared to the normal control group. Additions of fresh or once-heated palm or soy oil into high cholesterol diet seem to have improved the dynamic parameters towards the normal control values. However, when these oils were repeatedly heated, the protective effects were lost and the dynamic parameters except MS/BS dropped back towards the ovariectomised-control values.
Oils ; Diet ; Cholesterol ; Skeletal bone ; Rattus norvegicus

INTRODUCTIONGlucocorticoids cause osteoporosis by decreasing bone formation and increasing bone resorption activity. Glucocorticoid action in bones depends on the activity of 11-beta-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzyme, which plays an important role in regulating corticosteroids. 11β-HSD1 is expressed by human and rat osteoblasts. We aimed to investigate the relationship between 11β-HSD1 dehydrogenase activity and bone histomorphometric changes in glucocorticoid-induced osteoporotic bone in rats.

METHODSA total of 30 male Sprague-Dawley rats (aged three months, weighing 200-250 g) were divided into three groups of ten each. Group 1 rats were the baseline control, which were sacrificed untreated at the beginning of the study. Group 2 rats underwent sham operation and were administered with vehicle olive oil intramuscularly at 0.05 ml/kg. Group 3 rats were adrenalectomised and administered with an intramuscular injection of dexamethasone 120 μg/kg body weight/day. The treatment was started two weeks after the operation, for a duration of two months. Plasma osteocalcin, plasma pyrodinoline, plasma corticosterone and 11β-HSD1 were measured, and bone histomorphometry analysis was performed.

RESULTSDexamethasone treatment caused an increase in plasma corticosterone level, together with a significant reduction in 11β-HSD1 dehydrogenase activity of the bone, along with a higher plasma level of the bone resorption marker, pyridinoline. Dexamethasone treatment also caused a reduction in trabecular volume, number and thickness, and an increase in trabecular separation.

CONCLUSIONLong-term glucocorticoid treatment reduces the 11β-HSD1 dehydrogenase activity in the bone, which can otherwise lead to bone loss due to the increased level of active glucocorticoids.

11-beta-Hydroxysteroid Dehydrogenase Type 1 ; metabolism ; Adrenal Cortex Hormones ; metabolism ; Amino Acids ; pharmacology ; Animals ; Body Weight ; Bone and Bones ; metabolism ; Corticosterone ; blood ; Dexamethasone ; pharmacology ; Enzyme-Linked Immunosorbent Assay ; methods ; Gene Expression Regulation, Enzymologic ; Glucocorticoids ; metabolism ; Humans ; Male ; Osteoporosis ; metabolism ; Rats ; Rats, Sprague-Dawley

Long term glucocorticoids administration induces oxidative stress which leads to alteration of bone structure and strength. Palm oil is rich in tocotrienol, an antioxidant. It can be used for the prevention of oxidative stress related diseases. The main objective of this study was to determine the mechanism of palm tocotrienol in maintaining the bone structure and strength in glucocorticoid-induced osteoporosis. Thirty two adult male Sprague-Dawley rats, aged 3 months, weighing 300-320 g rats were used in this study. Sixteen rats undergone adrenalectomy and were administered with 120μg/kg/day intramuscular injection of dexamethasone. Eight rats were supplemented with oral palm tocotrienol 60 mg/kg/day (Adrx+Dex+PTT) and the other eight rats were given oral vehicle palm olein 0.1 ml/kg/day (Adrx+Dex). Eight rats underwent sham procedure and were given vehicle palm olein 0.05 ml/kg/day by intramuscularly and oral 0.1 ml/kg/day (Sham). The rats were euthanized after two months of treatments. Eight rats were euthanized after acclimatic action without receiving any treatment (Baseline). The right femurs were used for bone biomechanical strength and histomorphometry analysis while the left for gene expression and oxidative stress enzymes activities. The results indicated that long-term glucocorticoid treatment significantly increased bone resorption marker, CTX (6060.7 ± 410 pg/ml) and decreased bone structure and strength. Osteoblast and osteoclast related genes expressions indicated an increase in bone turnover. Supplementation of palm tocotrienol had maintained serum resorption (2619.4 + 209 pg/ml) marker level and preserved bone structure and strength. Gene expression analysis showed decrease in bone resorption. The findings suggested that palm tocotrienol has potential benefits against glucocorticoid-induced osteoporosis by regulating osteoblast and osteoclast related gene expression