Baseline Control Rats Research Articles

Anti-leukemogenic Efficacy of Aloe vera Gel on Benzene-induced Leukemia in Wistar Rats

Backgroud: The toxicity of benzene leading to leukemia induction has been well documented in animal model. Aloe vera is a succulent perennial evergreen flowering plant used traditionally in the treatment of jaundice and was found to have potent cytotoxic effect against HL60 human acute myeloid leukemia. The present study investigated the in vivo chemoprotective effects of Aloe vera gel on benzene-induced leukemia in rats.
 Methodology: Leukemia was induced in male Wistar rats of 80-90g weight by intravenously administered 0.2ml benzene solution alternate days for four weeks. Following induction, leukemic rats and normal baseline control rats were randomly assigned into four experimental groups of 6 animals each as follows: Group CTRL (control), normal baseline control rats; Group AVG (Aloe vera gel), normal baseline rats treated with Aloe vera gel (150 mg/kg) for 7 days, Group LKR (leukemic rats), untreated leukemic rats serving as leukemia control and Group LKR + AVG, leukemic rats treated with Aloe vera gel (150 mg/kg) for 7 days.
 Results: Leukemic rats showed altered hematology and morphological deformations such as anisocytosis, poikilocytosis and blast cells occurrence in peripheral blood. Also hypercellularity, severe dysplasia and significantly elevated micronucleated polychromatic erythrocyte were observed in marrow of leukemic rats. Moreover, benzene caused a significant elevation in plasma level of advanced oxidation protein products (AOPPs) with concomitant reduction in total sulfhydryl and arylesterase activity. However, treatment with Aloe vera gel restored blood hematology to near normal and mitigated the deformities in blood cell morphology induced by benzene. Aloe vera supplementation also effected a disappearance of dysplasia and diminution in the frequency of micronucleus in the bone marrow of treated leukemic rats. It also enhanced plasma antioxidant capability by restoring sulfhydryl content and arylesterase activity of the blood and abrogated the increase in plasma content of AOPPs.
 Conclusion: Overall, Aloe vera gel offered chemoprotective effect on Benzene-induced leukemia in rats.

The effects of long-term moderate exercise and Western-type diet on oxidative/nitrosative stress, serum lipids and cytokines in female Sprague Dawley rats

PurposeRegular exercise reduces obesity and the risk of cardiovascular disease. However, health-promoting benefits of physical activity are commonly associated with increased inflammation and oxidative stress. Here, we tested whether constant moderate exercise is able to prevent or attenuate the oxidative/nitrosative stress, inflammation, and serum lipids in lean and obese rats.MethodsFour-month-old female Sprague Dawley rats received standard or a high-fat diet. Animals were subjected to a physical activity protocol, consisting of 30 min forced treadmill exercise for 5 consecutive days per week during 10 months. Baseline and sedentary (non-exercised) rats were used as controls. Lipids, oxidized low-density lipoprotein cholesterol, nitric oxide metabolites, and pro- and anti-inflammatory markers were measured in blood collected upon euthanasia.ResultsAt variance to young baseline control rats, 14-month-old animals fed normal diet had increased plasma lipid levels, including total cholesterol and triglycerides, which were further elevated in rats that consumed a high-fat diet. While treadmill exercise did not lower the amount of serum lipids in standard diet group, forced physical activity reduced non-high-density lipoprotein cholesterol in response to high-fat diet feeding. Exercised rats fed standard diet or high-fat diet had lower abundancy of nitric oxide metabolites, which coincided with increased levels of oxidized low-density lipoprotein cholesterol. Accordingly, the amount of nitric oxide metabolites correlated inversely with oxidized low-density lipoprotein cholesterol and homo-arginine. Exercise significantly reduced inflammatory cytokines in high-fat diet fed rats only.ConclusionOur study suggests that regular exercise alters the equilibrium between oxidative and anti-oxidative compounds and reduces pro-inflammatory cytokines.

Hypothalamic leptin gene therapy reduces body weight without accelerating age-related bone loss

Excessive weight gain in adults is associated with a variety of negative health outcomes. Unfortunately, dieting, exercise, and pharmacological interventions have had limited long-term success in weight control and can result in detrimental side effects, including accelerating age-related cancellous bone loss. We investigated the efficacy of using hypothalamic leptin gene therapy as an alternative method for reducing weight in skeletally-mature (9 months old) female rats and determined the impact of leptin-induced weight loss on bone mass, density, and microarchitecture, and serum biomarkers of bone turnover (CTx and osteocalcin). Rats were implanted with cannulae in the 3rd ventricle of the hypothalamus and injected with either recombinant adeno-associated virus encoding the gene for rat leptin (rAAV-Leptin, n=7) or a control vector encoding green fluorescent protein (rAAV-GFP, n=10) and sacrificed 18 weeks later. A baseline control group (n=7) was sacrificed at vector administration. rAAV-Leptin-treated rats lost weight (-4±2%) while rAAV-GFP-treated rats gained weight (14±2%) during the study. At study termination, rAAV-Leptin-treated rats weighed 17% less than rAAV-GFP-treated rats and had lower abdominal white adipose tissue weight (-80%), serum leptin (-77%), and serum IGF1 (-34%). Cancellous bone volume fraction in distal femur metaphysis and epiphysis, and in lumbar vertebra tended to be lower (P<0.1) in rAAV-GFP-treated rats (13.5 months old) compared to baseline control rats (9 months old). Significant differences in cancellous bone or biomarkers of bone turnover were not detected between rAAV-Leptin and rAAV-GFP rats. In summary, rAAV-Leptin-treated rats maintained a lower body weight compared to baseline and rAAV-GFP-treated rats with minimal effects on bone mass, density, microarchitecture, or biochemical markers of bone turnover.

The protective effect of erythropoietin on the acute phase of corrosive esophageal burns in a rat model

An experimental study was conducted to investigate the effects of erythropoietin on the acute phase of esophageal burn damage induced by sodium hydroxide. A standard esophageal alkaline burn was produced by the application of 10% sodium hydroxide to the distal esophagus in an in vivo rat model. Fifty-six female rats were allocated into three groups: Group BC (baseline control, n = 8) rats were uninjured and untreated, Group PC (positive control, n = 24) rats were injured but untreated and Group EPO (erythropoietin-treated, n = 24) rats were injured and given subcutaneous erythropoietin (1,000 IU/kg per day), 15 min, 24, and 48 h after administration of the NaOH solution. Six animals from Group PC and six from Group EPO were killed at 4, 24, 48, and 72 h after application of NaOH to the esophagus. All of animals in Group BC were killed 4 h after exposure to 0.9% NaCl. Oxidative damage was assessed by measuring levels of malondialdehyde (MDA) and nitric oxide (NO), and activities of superoxide dismutase (SOD) and catalase (CAT) in homogenized samples of esophageal tissue. Histologic damage to esophageal tissue was scored by a single pathologist blind to groups. MDA levels in the BC and EPO groups were significantly lower than those in the PC group (p < 0.05). CAT and SOD activities, and NO levels in the BC and EPO groups were significantly higher than in the PC group (p < 0.05). Esophageal tissue damage measured at 4, 24, 48, and 72 h after NaOH application was significantly less in the EPO group than in the PC group (p < 0.05). When administered early after an esophageal burn induced by 10% sodium hydroxide in this rat model, erythropoietin significantly attenuated oxidative damage, as measured by biochemical markers and histologic scoring.

Longitudinal changes of bone microstructure and biomechanical properties of vertebral trabeculae in OVX rats

Objective To characterize the longitudinal changes of cancellous bone microstructural deterioration of vertebral trabeculae and to investigate the possible adaptative compensations in OVX rats.Methods 50 Female Sprague -Dawley rats of seven-month-old were ovariectomized(OVX),SHAM-operated(SHAM) or left unoperated(baseline control).The vertebral bodies and artery blood samples were harvested at baseline,3 and 15 weeks postoperatively.The compressive test was performed on L_5 vertebral body,and micro-computed tomography(μ-CT) assessment was performed to estimate 3D bone mineral density(BMD) and microstructure parameters of the L_6 vertebral body.After fatigue damage testing,L_6 vertebral body was bulk-stained in 1%basic fuchsin and embedded in methylmethacrylate.Mounted bone slices were used to measure osteocyte density(Ot.N/T.Ar).Blood samples were used to analyze serum tartrate-resistant acid phosphatase 5b(TRAP-5b).Results At 3 weeks postoperatively,apparent BMD,trabecular volume fraction(TV/ BV),trabecular thickness(Tb.Th),trabecular number(Tb.N),tartrate-resistant acid phosphatase 5b(TRAP-5b), maximum load(ML),elastic modulus(EM) and osteocyte density(Ot.N/T.Ar) were significantly decreased in OVX rats than those of SHAM and baseline control rats.Degree of anisotropy(DA) was significantly decreased in OVX rat than those of baseline control group.Bone area density(BS/BV),trabecular separation(Tb.Sp) and trabecular model index (SMI) were significantly increased in OVX rat than those of SHAM and baseline control rats.There were no significant differences between OVX and SHAM rats with regard to DA,trabecular connectivity density(Conn.D),ML,EM,Ot N/ T.Ar and TRAP-5b.There was no significant difference with regard to Conn.D between OVX and baseline control rats. At 15 weeks postoperatively,apparent BMD,TV/BV,Conn.D,Tb.N,TRAP-5b,ML and Ot N/T.Ar were significantly decreased in OVX rat than those of SHAM and baseline control rats.SMI,Tb.Sp and DA were significantly increased in OVX rat than that of SHAM and baseline control rats.There were no significant differences with regard to BS/BV and Tb.Th.between OVX,SHAM and baseline control rats.BS/BV,Conn.D and Tb.N of OVX rat were significandy decreased at 15 weeks postoperatively than those at 3 weeks postoperatively.Ot N/T.Ar,Tb.Sp and DA of OVX group were significantly increased at 15 weeks postoperatively than those at 3 weeks postoperatively.Conclusion In early ovariectomized rats,bone mass of lumbar vertebra lost rapidly while the microstructure of spongy bone deteriorated gradually.A decrease in serum TRAP-5b,and an increase in osteocyte density,trabecular degree of anisotropy and trabecular thickness might represent the adaptive changes to the attenuated bone quality accounting for maintenance of the strength and integrity of cancellous bone in OVX rats.

Time course of femoral neck osteopenia in ovariectomized rats

To characterize osteopenic changes in the femoral neck of ovariectomized (ovx) rats, female Sprague-Dawley rats were ovx or sham operated upon at 3 months of age and killed at various times from 0 to 360 days postsurgery. Quantitative bone histomorphometry was performed on undecalcified longitudinal sections of the proximal femur from each rat. This skeletal site was found to be slowly growing, as its rate of longitudinal bone growth in 3-month-old baseline control rats (5 μm/day) was nearly a factor of 10 less than that of a more commonly used sample site, the proximal tibia. In control rats, cancellous bone volume and cortical bone width of the femoral neck remained relatively constant, but cancellous mineral apposition rate declined with age during the course of the study. In contrast, cancellous bone volume in ovx rats was significantly decreased to 75%–82% of control level at 30–90 days and further decreased to 50%–56% of control level at later times postovariectomy. Indices of cancellous bone turnover such as osteoclast and osteoblast surfaces and bone formation rate were markedly increased in ovx rats at 30 days, declined toward control levels by 90 days, then increased moderately at 180–360 days. In comparison to control rats, a slight decrease in cortical width of the femoral neck was observed in ovx rats at 180 days and reached statistical significance at 360 days postovariectomy. Endocortical bone formation rate was increased significantly in ovx rats compared with control rats at most time points. The results indicate that both cancellous and cortical osteopenia associated with high bone turnover occur in the femoral neck of ovx rats. Cancellous bone loss at this skeletal site is statistically significant as early as 30 days postovariectomy, but remains relatively moderate for the first 90 days before becoming more pronounced at later times after ovariectomy. In contrast, cortical osteopenia was not observed in the femoral neck of ovx rats until 1 year postovariectomy. This histomorphometric characterization of osteopenic changes in the femoral neck of ovx rats may serve as a basis for use of this slowly growing sample site in preclinical studies of the prevention and treatment of bone loss in the estrogen-depleted skeleton.

Effect of ovariectomy on cancellous bone in the hypophysectomized rat.

This experiment studied the effects of hypophysectomy (HX) and ovariectomy (OV) on cancellous bone in the proximal tibia and distal 5th lumbar vertebra by dynamic histomorphometry. Forty-eight female Sprague-Dawley rats, 3 months of age, were divided into age-matched control, HX, OV, and HX + OV (HO) groups. Ten rats were sacrificed at 3 months of age as baseline controls, and the rest of the animals were sacrificed 5 weeks after the surgery. While the age-matched controls, and the OV rats significantly increased in body weight compared with the baseline control rats, cancellous bone volumes in the proximal tibia and distal 5th lumbar vertebra increased in the age-matched controls and decreased in the OV rats. In the HX and HO rats, body weight equaled baseline control values, and their cancellous bone volumes were decreased with a poorer trabecular architecture in both bone sites. In all HX, OV, and HO rats, uterine weight and serum estradiol were significantly decreased. OV significantly increased longitudinal bone growth and the tissue- and surface-based bone formation and bone resorption parameters in both the proximal tibia and 5th lumbar vertebra (p < 0.05). HX alone or HO significantly decreased longitudinal bone growth and the tissue-based bone formation rate without significantly affecting surface-based bone formation and bone resorption parameters when compared with the age-matched controls. No significant differences were detected in any variables between the HX alone and HO rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Dietary fat affects weight loss and adiposity during energy restriction in rats

This study examined the effect of dietary fat during food restriction on weight loss, body composition, and adipose tissue lipoprotein lipase activity (ATLPL). Rats previously fed a high-fat diet were divided into four groups. One group served as baseline controls. The other three groups were fed diets of 12%, 28%, or 45% fat, restricted (R) in amounts to equal 75% of their previous ad libitum energy intake. After 10 wk, body weight loss and reduction of adiposity were significantly less in the 45%-R group compared with the 12%-R group (weight P < 0.05; adiposity P < 0.01). Rats fed restricted amounts of the high-fat diet (45%-R group) retained adiposity equivalent to baseline control rats. ATLPL activity was increased in the 45%-R group compared with baseline control rats. Further studies are needed in humans, but these results suggest that body composition will not be normalized with reduction of energy intake unless dietary fat is also reduced.