Bone biomarkers of ovariectomised rats after leptin therapy.

BACKGROUND AND AIM: Under physiological conditions, maintenance of skeletal mass is the result of a tightly coupled process of bone formation and bone resorption. Disease states, osteoporosis included, arise when this delicate balance is disrupted, such as in menopause. The aim of the present work was to study the effect of leptin supplementation on bone metabolism in ovariectomized adult female rats by measuring indices of bone biomarkers. METHODS: Forty adult female albino rats were chosen as an animal model for this study and divided into the four equal groups (n=10/group): Group I (control SHAM-operated group) received a single dose of buffer solution i.p. daily for eight weeks. Group II (ovariectomy group) received a single dose of buffer solution i.p. daily for eight weeks. Group III (alendronate group): Ovariectomized rats that received alendronate 0.1 mg/kg body weight i.p. daily for eight weeks. Group IV (leptin group): Ovariectomized rats that received leptin (10 µg/kg body weight) i.p. daily for eight weeks. The obtained serum is required for determination of: Serum osteocalcin, alkaline phosphatase, calcium and phosphorous levels. RESULTS: The obtained data revealed that treatment with alendronate or leptin caused a significant decrease of serum osteocalcin, specific bone alkaline phosphatase and urinary deoxypyridinoline levels compared to ovariectomy group, and there was no significant difference between both drugs. CONCLUSION: Leptin prevents ovariectomy induced increases in bone turnover in rats. Leptin therapy has a significant effect in treatment of ovariectomy induced osteoporosis in rats (Tab. 1, Ref. 32).

Effect of dexmedetomidine and cold stress in a rat model of neuropathic pain: Role of interleukin-6 and tumor necrosis factor-α.

Dexmedetomidine (Dex) is a novel Alpha 2-adrenoceptor agonist. It decreases sympathetic tone and attenuates the stress responses to anesthesia and surgery. People exposed to cold suffer unpleasant thermal pain, which is experienced as stress and causes the release of noradrenaline from the sympathetic terminals. The present study investigated the effects of cold stress and dexmedetomidine on chronic constriction injury (CCI) model of the sciatic nerve in rats. Sixty four male Wistar rats were divided into seven groups of eight rats each: repeated cold stress (RCS) group, sham RCS group, CCI group, sham CCI group, Dex-treated group received a single dose of Dex (5 µg/kg), CCI+Dex group, CCI+RCS group. Interleukin-6 (IL-6) and tumor necrosis factor- alpha (TNF-α) levels in the serum were measured by enzyme-linked immunosorbent assay. The mean body weight of CCI, RCS, CCI+RCS, CCI+Dex and RCS+Dex groups decreased significantly compared with pre-values. Dexmedetomidine and CCI caused significant changes of the systolic, diastolic and mean blood pressure. Both RCS and CCI groups showed significant decreased of reaction time in the hot plate test. The RCS and CCI groups demonstrated a significant mechanical hyperalgesia, while pain threshold was increased in the RCS+Dex group. A significant decrease of serum IL-6 and TNF-α was demonstrated in CCI+RCS and CCI+Dex groups. The therapeutic effectiveness of dexmedetomidine in neuropathic pain may be through inhibition of proinflammatory cytokines, primarily IL-6 and TNF-α. Moreover, cold stress may result in increased resistance to neuropathic pain.

Comparing the effects of inorganic nitrate and allopurinol in renovascular complications of metabolic syndrome in rats: role of nitric oxide and uric acid.

INTRODUCTION: The epidemic of metabolic syndrome is increasing worldwide and correlates with elevation in serum uric acid and marked increase in total fructose intake. Fructose raises uric acid and the latter inhibits nitric oxide bioavailability. We hypothesized that fructose-induced hyperuricemia may have a pathogenic role in metabolic syndrome and treatment of hyperuricemia or increased nitric oxide may improve it. MATERIAL AND METHODS: Two experiments were performed. Male Sprague-Dawley rats were fed a control diet or a high-fructose diet to induce metabolic syndrome. The latter received either sodium nitrate or allopurinol for 10 weeks starting with the 1(st) day of fructose to evaluate the preventive role of the drugs or after 4 weeks to evaluate their therapeutic role. RESULTS: A high-fructose diet was associated with significant (p < 0.05) hyperuricemia (5.9 ±0.5 mg/dl), hypertension (125.2 ±7.8 mm Hg), dyslipidemia and significant decrease in tissue nitrite (27.4 ±2.01 mmol/l). Insulin resistance, as manifested by HOMAIR (20.6 ±2.2) and QUICKI (0.23 ±0.01) indices, as well as adiposity index (12.9 ±1.1) was also significantly increased (p < 0.1). Sodium nitrate or allopurinol was able to reverse these features significantly (p < 0.05) in the preventive study better than the therapeutic study. CONCLUSIONS: Fructose may have a major role in the epidemic of metabolic syndrome and obesity due to its ability to raise uric acid. Either sodium nitrate or allopurinol can prevent this pathological condition by different mechanisms of action.

The gender difference of selective serotonin reuptake inhibitor, fluoxetine in adult rats with stress-induced gastric ulcer.

We investigated the gender difference of selective serotonin reuptake inhibitor, fluoxetine in adult rats with stress-induced gastric ulcer. The rats were randomly divided into six groups: Group I, control males and group II, control females; group III, acute cold restraint stressed males and group IV, acute cold restraint stressed females; group V, fluoxetine-treated stressed males and group VI, fluoxetine-treated stressed females. Acute cold restraint stress was established by fixing the four limbs of the rat and placing it in a refrigerator at 4°C for 3h. Fluoxetine was given intraperitoneal in a single dose of 10mg/kg/day. After 2 weeks, stomach and brain tissues were collected for the assay of gastric malonaldehyde (MDA), catalase, nitric oxide (NO) and cortical gamma aminobutyric acid (GABA). Stressed animals exhibited increased total acidity in association with decreased gastric secretion volume. Gastric MDA was increased while gastric catalase, NO, and cortical GABA were decreased in stressed male rats when compared to stressed females. However, fluoxetine administration attenuated these stress-induced changes especially in stressed male animals. Stressed male rats were more responsive to the antiulcer effect of fluoxetine more than stressed females. However, fluoxetine might be considered to be the first-choice drug in depressive patients with gastric ulcers in the future.

Gastroprotective effects of Nigella Sativa oil on the formation of stress gastritis in hypothyroidal rats.

The aim of this study was to assess the effects of hypothyroidism on the development of acute cold restraint stress gastritis in rats and protective effect of Nigella sativa at the beginning of the acute cold restraint stress. 60 rats were randomly divided into six groups; the control (groups I), surgically thyroidectomized group (group II), acute cold restraint stressed group (group III), surgically thyroidectomized plus stressed group (group IV), Nigella sativa oil group (group V) and surgically thyroidectomized plus stressed plus Nigella sativa oil group (group VI). Volume of gastric juice, number and size of ulcer, gastric malonaldehyde, gastric glutathione, gastric protein and serum thyroxine (T4) were measured. Significant increases both of number of gastric ulcer and malonaldehyde while decreases both of glutathione and protein levels in rats in groups III and IV in comparison with control group. While, insignificant increase were observed between control and both of groups II and VI. In rats, low thyroid hormone level increase stress gastritis, and this effect can be decreased by treatment with Nigella sativa.