High-lipid diet intake is a possible predisposing factor in the development of hypogonadal osteoporosis

Protective efficacy of folic acid and vitamin B12 against nicotine-induced toxicity in pancreatic islets of the rat

Although cigarette smoking is associated with insulin resistance and an increased risk for type 2 diabetes, few studies have examined the effect of nicotine on the adult endocrine pancreas. In this study, male Wister rats were treated with nicotine (3 mg/kg body weight/ day) with or without supplementation of folic acid (36 μg/kg body weight/day) or vitamin B12 (0.63 μg/kg body weight/day) alone or in combination. Fasting blood glucose, insulin and HBA1C level and different oxidative and anti-oxidative stress parameters were measured and pancreatic tissue sections were stained with eosin-haematoxylene. Data were analysed by nonparametric statistics. The results revealed that nicotine induced prediabetes condition with subsequent damage to pancreatic islets in rats. Nicotine also caused oxidative stress in pancreatic tissue as evidenced by increased nitric oxide and malondialdehyde level and decreased superoxide dismutase, catalase and reduced glutathione level. Compared to vitamin B12 supplementation, folic acid blunted the nicotine-induced toxicity in pancreatic islets with higher efficacy. Further, folic acid and vitamin B12 in combination were able to confer significant protection on pancreatic islets against nicotine induced toxicity. These results suggest that supplementation of folic acid and vitamin B12 in combination may be a possible strategy of detoxification against nicotine-induced toxicity in pancreatic islets of the rat.

Arsenic-induced hepatic mitochondrial toxicity in rats and its amelioration by diallyl trisulfide

The present investigation was aimed to investigate the possible protective role of diallyl trisulfide (DATS) against arsenic (As)-induced hepatic mitochondrial toxicity in rats. Mitochondria were isolated from the liver tissue of rats from all the groups. Lipid profile, lipid peroxidation, antioxidant enzyme activities, hepatic function enzymes, mitochondrial swelling, cytochrome c oxidase activity, mitochondrial Ca(+)-ATPase and Na(+)/K(+)-ATPase activity, mitochondrial calcium content and mitochondrial enzyme activities were measured. Short-term As exposure (5 mg/kg bw/d for 28 d) caused liver damage as evidenced by changes in activities of liver enzymes. The effects of As were coupled with enhanced reactive oxygen species generation, mitochondrial swelling, inhibition of cytochrome c oxidase, complex I-mediated electron transfer, decreased Ca(2+)-ATPase and Na(+)/K(+)-ATPase activity, a reduction in mitochondrial calcium content, changes in indices of hepatic mitochondrial oxidative stress, significant increase in mitochondrial lipid peroxidation products and alterations in mitochondrial lipid profile. Significant decreases in mitochondrial antioxidants and tricarboxylic acid cycle enzymes were also found in the liver mitochondria of As-induced hepatic mitochondrial toxicity in rats. As also increased hepatic caspase-3 activity and DNA fragmentation. All these apoptosis-related molecular changes caused by As could be alleviated by supplementation with DATS, which likely suggests a protective role against As-induced hepatotoxic changes and hepatic mitochondrial toxicity. The protective effect of DATS on the liver mitochondria was evidenced by altering all the changes induced by As. Free radical scavenging and metal chelating activities of DATS may be the mechanism, responsible for the protective action against As-induced mitochondrial damage in liver.

Diallyl trisulfide ameliorates arsenic-induced hepatotoxicity by abrogation of oxidative stress, inflammation, and apoptosis in rats

The present study investigates the possible ameliorative effects of diallyl trisulfide (DATS) against arsenic (As)-induced hepatotoxicity and oxidative stress in rats. The four experimental groups evaluated include: (1) vehicle control; (2) As (5 mg/kg/day); (3) DATS (80 mg/kg/day) + As; and (4) DATS. Induction of As in rats caused severe hepatotoxicity as evidenced by an elevation of serum aspartate aminotransferase and alanine aminotransferase activities and increased total bilirubin concentration, indicating hepatic function abnormalities. Histopathological examination revealed various structural changes in the liver, characterized by hepatocyte degeneration/necrosis, congestion, sinusoidal dilatation, vacuolation, and inflammatory cell infiltration. The significant decrease in reduced glutathione content, catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase activities and the significant increase in lipid peroxidation (thiobarbituric acid reactive substance) and protein oxidation (protein carbonyl) contents indicated that As-induced hepatotoxicity was mediated through oxidative stress. As intoxication also elevated the levels of Cas-3 and nitric oxide and increased the expression of nuclear factor-κB p65 in the liver. In contrast, DATS pretreatment significantly improved As-induced serum biochemical, immunohistochemical, and histopathological alterations reflecting hepatic dysfunction. These results may contribute to a better understanding of the hepatoprotective role of DATS, emphasizing the influence of this garlic trisulfide in the diet for human health, possibly preventing the hepatic injury associated with As intoxication, presumably due to its ability to inhibit lipid peroxidation, protein oxidation, and restoration of antioxidant status.

Black tea may be a prospective adjunct for calcium supplementation to prevent early menopausal bone loss in a rat model of osteoporosis

The present study was undertaken to find out the ability of black tea extract (BTE) as a suitable alternative of adjunct for calcium supplementation in treating an ovariectomized rat model of early osteoporosis. Female Wistar rats weighing 140-150 g were divided into four groups consisting of six animals in each group: (A) sham-operated control; (B) bilaterally ovariectomized; (C) bilaterally ovariectomized + BTE; (D) bilaterally ovariectomized + 17 β -estradiol. Results suggest that BTE could promote intestinal absorption of calcium significantly (P < 0.01 for duodenum and ileum; and P < 0.05 for jejunum). This was found associated with enhanced activities of two relevant intestinal mucosal enzymes alkaline phosphatase (P < 0.01 for duodenum, jejunum, and ileum) and Ca(2+) activated ATPase (P < 0.01 for duodenum, jejunum, and ileum). Such BTE-mediated promotion of calcium absorption was coupled with increase in serum estrogen titer (P < 0.01) and recovery of all urinary, bone, and serum osteoporotic marker parameters, including bone histological features. Serum parathyroid hormone level, however, was not altered in these animals (P > 0.05). A comparative study with 17 β -estradiol, a well-known adjunct for calcium supplementation, indicated that efficacy of BTE in maintaining skeletal health is close to that of 17 β -estradiol. This study suggests that simultaneous use of BTE is promising as a prospective candidate for adjunctive therapies for calcium supplementation in the early stage of menopausal bone changes.

Antiapoptotic efficacy of folic acid and vitamin B₁₂ against arsenic-induced toxicity

Earlier, we proposed that the ability of folic acid and vitamin B₁₂ to preserve systemic and mitochondrial function after short-term exposure to arsenic may prevent further progression to more permanent injury and pathological changes leading to cell death. To elucidate its mechanism, the present study examined the antiapoptotic efficacy of folic acid and vitamin B₁₂ against short-term arsenic exposure-induced hepatic mitochondria oxidative stress and dysfunction. Sixteen to eighteen weeks old male albino rats weighing 140-150 × g were divided into five groups: Control (A), Arsenic-treated (B), Arsenic + folic acid (C), Arsenic +vitamin B₁₂ (D), and Arsenic + folic acid + vitamin B₁₂ (E). Data generated indicated that folic acid and vitamin B₁₂ separately or in combination can give significant protection against alterations in oxidative stress and apoptotic marker parameters and downstream changes in mitochondria, namely pro-oxidative (NO, TBARS, OH⁻) and antioxidative defense (SOD, CAT, GSH) markers, iNOS protein expression, mitochondrial swelling, cytochrome c oxidase and Ca²⁺-ATPase activity, Ca²⁺ content, caspase-3 activity. Additionally, results of hepatic cell DNA fragmentation, arsenic load of blood, hepatic tissue and urine, and histological observations, all strongly support that both these supplements have efficacy in preventing apoptotic changes and cellular damage. As the mechanisms of actions of both of these supplements are methylation related, a combined application was more effective. Results further reveal new molecular targets through which folic acid and vitamin B₁₂ separately or in combination work to alleviate one critical component of arsenic-induced liver injury: mitochondria dysfunction.

Clove (Syzygium aromaticum Linn) extract rich in eugenol and eugenol derivatives shows bone-preserving efficacy

This study examined the efficacy of hydroalcoholic extract of dried clove buds, which is rich in phenolic compounds namely eugenol and eugenol derivatives (precursors of flavones, isoflavones and flavonoids), on different primary and secondary osteoporotic marker changes in an ovariectomised (OVX) rat model of osteoporosis. Female Wistar rats were randomly divided into three groups: sham-operated control (A), OVX (B) and OVX plus 50% hydroalcoholic extract of dried clove buds for 4 weeks (C). Results indicated that, compared to control, serum alkaline phosphatase (AP; 48.25%, p < 0.01), serum tartrate-resistant acid phosphatase (TRAP; 63.48%, p < 0.01), urinary calcium (14.70%, p < 0.01), urinary phosphate (50.30%, p < 0.01) and urinary creatinine (122.44%, p < 0.01) were significantly altered in OVX rats. All these altered responses were significantly restored (AP: 27.53%, p < 0.01; TRAP: 33.51%, p < 0.01; calcium: 53.15%, p < 0.01; phosphate: 27.49%, p < 0.01; creatinine: 46.40%, p < 0.01) by supplementation with hydroalcoholic extract of dried clove buds. Results of bone density, bone mineral content, bone tensile strength and histological analysis also showed similar trend of results, which supported initial observations of this study. It is proposed that hydroalcoholic extract of dried clove buds has bone-preserving efficacy against hypogonadal osteoporosis.

Protective Role of Black Tea Extract against Nonalcoholic Steatohepatitis-Induced Skeletal Dysfunction

Aim. This paper aimed to examine the chemoprotective actions of aqueous black tea extract (BTE) against nonalcoholic steatohepatitis- (NASH-) induced skeletal changes in rats. Material. Wistar rats (body wt. 155-175 g) of both sexes, aged 4-5 months, were randomly assigned to 3 groups; Group A (control), Group B (60% high-fat diet; HFD), and Group C (HFD + 2.5% BTE). Methods. Several urinary (calcium, phosphate, creatinine, and calcium-to-creatinine ratio) serum (alkaline phosphatase and serum tartrate-resistant acid phosphatase), and molecular markers of bone turnover (receptor activator of NF-κB ligand (RANKL), osteoprotegerin (OPG), and estrogen) were tested. Also, several bone parameters (bone density, bone tensile strength, bone mineral content, and bone histology) and calcium homeostasis were checked. Results. Results indicated that HFD-induced alterations in urinary, serum, and bone parameters as well as calcium homeostasis, all could be significantly ameliorated by BTE supplementation. Conclusion. Results suggest a potential role of BTE as a protective agent against NASH-induced changes in bone metabolism in rats.

Arsenic-induced hepatic mitochondrial toxicity in rats and its amelioration by dietary phosphate

The present study was aimed to test the hypothesis that inorganic phosphate may reduce arsenic toxicity by decreasing its intestinal transference. Co-administration of inorganic phosphate (6.56 M) and arsenic (6.07 mM) in the intestinal loops of rats, in situ, caused significant reduction of arsenic transference. Short-term arsenic exposure (3mg/kg body weight/day for 30 days) caused liver damage evidenced by activities of liver enzymes and necroinflammatory changes. These effects of arsenic were coupled with enhanced mitochondrial swelling, inhibition of cytochrome c oxidase, Ca(2+)-ATPase, a decrease in mitochondrial calcium content, changes in indices of hepatic mitochondrial oxidative stress and iNOS expression. Arsenic also increased hepatic caspase 3 activity and DNA fragmentation. All these apoptosis-related molecular changes caused by arsenic could be alleviated by supplementation with inorganic phosphate, which likely suggests a protective role of phosphate against arsenic-induced hepatotoxic changes.

Folic acid or combination of folic acid and vitamin B(12) prevents short-term arsenic trioxide-induced systemic and mitochondrial dysfunction and DNA damage

The effect of folic acid and folic acid + vitamin B(12) supplementation upon short-term arsenic-induced systemic and pancreatic islet cell mitochondria oxidative stress was investigated in male rats. Arsenic trioxide was administered orally at a dose of 3 mg kg body weight(-1) day(-1) for 30 days, and folic acid and vitamin B(12) were administered at a dose of 36 and 0.63 microg kg body weight(-1) day(-1), respectively, for 30 days. Compared to control, arsenic-treated group showed a significant increase in the levels of systemic oxidative markers, malondialdehyde (MDA), nitric oxide (NO), and hydroxyl radical (OH(-)) formation, which were found decreased significantly after supplementation either with folic acid or a combination of folic acid + vitamin B(12). Similar supplementations were found effective against arsenic-induced oxidative marker changes (MDA, NO, and OH(-)) in pancreatic islet cell mitochondria. Also, low activities of antioxidant defense enzymes such as superoxide dismutase and catalase, and level of antioxidant glutathione, all could regain significantly on supplementations both against systemic and islet cell mitochondria oxidative stress. Results of agarose-gel electrophoresis of DNA from lymphocytes and islet cells of arsenic-exposed rats showed DNA smearing, which could be reduced with simultaneous administration either with folic acid or a combination of folic acid + vitamin B(12). Significantly, similar supplementations were found effective in increasing the urinary clearance of arsenic. Together, these results indicate that folic acid and vitamin B(12) may be effective to reduce the arsenic-induced damage at molecular target level.

Phytoestrogenic effects of black tea extract (Camellia sinensis) in an oophorectomized rat (Rattus norvegicus) model of osteoporosis

The adverse side effects of currently available anti-osteoporotic agents warrant the search for compounds with less toxic effects. In this study, we assessed the phytoestrogenic potentiality of whole aqueous extract of black tea (BTE) in a bilaterally oophorectomized rat model (2.5%, 1 ml/100 g body weight/day for 28 days). Although the supplementation was given for 28 days but, sign of revival of copulation period (estrous stage) from non-receptive diestrous stage was first noticed after 21 days of BTE supplementation in bilaterally oophorectomized rats. This was accompanied by a significant increase in serum estradiol level. To test whether this increase in serum estradiol level could have an influence upon the oophorectomy-induced damage of bone, we assessed marker parameters of bone resorption and osteoclastic activity (tartrate-resistant acid phosphatase), collagen degradation (urinary hydroxyproline), bone loss (bone ash mineral content) and bone breaking strength (bone density). Results indicated that increase in serum estradiol level after BTE supplementation could significantly diminish oophorectomy-induced decaying changes in bone. This study proposes that aqueous BTE may be assessed as a phytoestrogenic compound for prevention against estrogen deficiency-related osteoporotic damages.

Synergistic effect of folic acid and vitamin B12 in ameliorating arsenic-induced oxidative damage in pancreatic tissue of rat

The efficacies of two nutritional factors, folic acid and vitamin B12, were assessed in this study against arsenic-induced islet cellular toxicity. Rats were divided into four groups consisting of five rats in each group: Group A, control; Group B, arsenic-treated; Group C, arsenic+folic acid; and Group D, arsenic+folic acid+vitamin B12. The dose of arsenic, folic acid and vitamin B12, respectively, was 3 mg, 36 microg and 0.63 microg kg(-1) body weight day(-1) for 30 days. Results showed that, compared to control group, there was a significant increase in the levels of nitric oxide (NO), malondialdehyde (MDA) and hydroxyl radical (OH-) formation in the pancreatic tissue of arsenic-treated rats, while the activity of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), and cellular content of antioxidant glutathione (GSH) were low in these animals. The serum level of tumor necrosis factor-alpha (TNF-alpha) and IL-6 was significantly high in these animals. Light microscopic examination showed a marked fall in the number of islet cells. Concomitant administration of either folic acid or folic acid and vitamin B12 with arsenic significantly restored all these parameters. Although folic acid alone could not restore the normal level of TNF-alpha and IL-6, combined folic acid and vitamin B12 could restore it. Folic acid and vitamin B12 combined also could recover islet cell count. These results suggest that folic acid+vitamin B12 are capable of reducing arsenic-induced cellular oxidative and inflammatory toxic changes. Thus, supplement with vitamin B12+folic acid may be predicted as a possible nutritional management strategy against arsenic-induced toxicity.

Effects of dietary fats on bone health in advanced age

Evidence is accumulating that dietary lipids play an important role in bone health. Most of the data supporting the effects of lipids on bones have been collected in young adult and/or developing animals. Based upon this work, mechanisms have been proposed to explain how lipids act to enhance or inhibit bone resorption and deposition. Little work, however, has been done in older models. Since osteoporosis primarily afflicts the elderly, such work is needed in order to determine if mechanisms relevant to the young differ in advanced age, and to develop effective interventions for this especially vulnerable segment of the population. This article reviews evidence that dietary lipids are important to bone health in older individuals, and describes possible mechanisms that may be of particular relevance to the elderly. Specifically, studies supporting the influence of dietary lipids on calcium excretion, growth hormone secretion, fatty acid metabolism, and osteoblast formation are reviewed.

Diet, smoking and anthropometric indices and postmenopausal bone fractures: a prospective study

OBJECTIVE

Bone fractures are an important cause of morbidity and mortality among the elderly in the US. The present study assesses the possible role of a number of risk factors for postmenopausal bone fractures.

METHODS

We analysed the relationships of anthropometric, demographic and lifestyle factors with the risk of bone fracture among 6250 postmenopausal women in a prospective cohort study, the New York University Women's Health Study.

RESULTS

After an average of 7.6 years of follow-up, 1025 new incident bone fractures were reported, including 34 hip and 159 wrist fractures (incidence rates; 71.6 and 334.7 per 105 woman-years, respectively). The risk of fracture increased with increasing age, body height and total fat intake, while it was significantly lower among obese and African American women. The relative risk among African Americans was 0.45 (95% CI: 0.32-0.63) compared with non-African Americans. Women taller than 170 cm had a 64% increase in risk of fractures, as compared with those under 155 cm. These associations were generally more pronounced when fractures were limited to those at the hip and wrist.

CONCLUSIONS

The present study provides an indication for a potential role of dietary fat in the development of postmenopausal fractures and further evidence to support protective effects of obesity, short stature and African American ethnicity.

Cold stress facilitates calcium mobilization from bone in an ovariectomized rat model of osteoporosis

In an ovariectomized rat model of osteoporosis, the effects of cold stress on intestinal Ca2+ transference and rate of bone turnover were evaluated. In the ovariectomized rats, a significant reduction in intestinal transference of Ca2+ was associated with decreased activities of intestinal mucosal enzymes, alkaline phosphatase (AP), and calcium ATPase (Ca2+-ATPase) in all the different segments of small intestine in a descending gradient. The development of a high rate of bone turnover and osteoporosis in these animals was confirmed by significant alteration in plasma AP activity and calcium (Ca) level, urinary excretion of Ca and phosphate, and Ca : creatinine ratio. Cold stress in this model, apart from its unique influence in elevating plasma corticosterone and thyroid hormone level, enhanced all the above referred parameters studied in connection with intestinal transference of Ca2+, bone turnover rate, and osteoporosis. The results of this study emphasize that cold stress may have a positive influence on bone loss for an early development of hypogonadal osteoporosis in rats.