Effects of nadroparin on bone histomorphometric parameters in rats

Nadroparin calcium is a low-molecular-weight heparin. Low-molecular-weight heparins have a number of advantages over standard heparin (heparin), but it is not clear if low-molecular-weight heparins have less effect on bones than heparin. Administration of heparin can lead to osteoporosis. The aim of the present study was to investigate the effects of nadroparin on the rat osseous system and compare them with those of heparin. The experiments were carried out on female Wistar rats (13-15 weeks old at the beginning of the experiment), divided into 5 groups: I. Control, II. Nadroparin (1000 anti-Xa IU/kg s.c. daily), III. Nadroparin (2000 anti-Xa IU/kg s.c. daily), IV. Heparin (1000 IU/kg s.c. daily), V. Heparin (2000 IU/kg s.c. daily). Nadroparin and heparin were administered for 4 weeks. Bone mass, mineral and calcium content, macrometric and histomorphometric parameters (endosteal and periosteal transverse growth, width of endosteal and periosteal osteoid, transverse cross-section area of the cortical bone in the diaphysis and of the marrow cavity in the tibia, width of epiphyseal cartilage, width of trabeculae in the epiphysis and metaphysis in the femur) were examined. The effect of heparin on the ratio of bone mineral content to bone mass was more pronounced than that of nadroparin. Nadroparin caused unfavorable changes in the investigated bone histomorphometric parameters, similar to those caused by heparin. Nadroparin and heparin caused disorder of bone formation and intensification of bone resorption in rats.     

Effects of doxycycline on development of changes in histomorphometric parameters of bones induced by bilateral ovariectomy in rats

Tetracyclines are considered potential medication for the treatment of osteoporosis. The aim of the present study was to investigate the effects of doxycycline on development of unfavorable changes in bone histomorphometric parameters induced by bilateral ovariectomy in rats. Doxycycline at a dose of 20 mg/kg po daily was administered for 28 days to bilaterally ovariectomized and sham-operated 3-month-old Wistar rats. Bone histomorphometric parameters of the tibia (transverse growth, width of periosteal and endosteal osteoid, area of the transverse cross-section of the diaphysis and area of the transverse cross-section of the marrow cavity) and the femur (width of epiphyseal and metaphyseal trabeculae, width of epiphyseal cartilage) were examined. Bilateral ovariectomy caused symptoms of osteopenia in the rat bones. Doxycycline counteracted the unfavorable changes in bone structure caused by estrogen deficiency. However, in the sham-operated rats doxycycline itself induced deleterious effects in the trabecular bone.     

Effects of 6-mercaptopurine (6-MP) on histomorphometric parameters of the rat bones

6-Mercaptopurine (6-MP) is an antimetabolite. The drug inhibits DNA synthesis of cells by acting as a false analog of purines. 6-MP displays a cytostatic and immunosuppressive activity. The studies carried out so far focus mostly on recognizing the clinical effectiveness of 6-MP, particularly in treating autoimmune diseases, whereas its effect on the osseous tissue still remains unknown. We examined the effect of 6-MP on the osseous system in rats after a 4-week period of its administration by analyzing histomorphometric parameters and bone mass, mineral and calcium content. We also tested the reversal of the above changes after the lapse of 4 week-period during which 6-MP was not administered. Male Wistar rats were divided into 6 groups, each group was composed of 8 animals. Treatment of 6-MP started on day 2 of the experiment, and the drug was administered for 28 days, i.e. between day 2 and 29 in all groups examined. Changes in the histomorphometric parameters were examined in 3 groups 4 weeks after the first 6-MP or 0.9% NaCl administration: I - control group (0.9% NaCl solution), II - 6MP group (6-MP at the dose of 2.5 mg/kg po), III - 6-MP group (6-MP at the dose of 5 mg/kg po). Reversal of the changes was examined 8 weeks after the first 6-MP or 0.9% NaCl administration in 3 groups: IV - control group (0.9% NaCl solution), V - 6-MP group (6-MP at the dose of 2.5 mg/kg po), VI - 6-MP group (6MP at the dose of 5 mg/kg po). We demonstrated that 6-MP administered orally at a dose of 2.5 mg/kg po or at a dose of 5 mg/kg po for the period of 4 weeks inhibited the synthesis and mineralization of the osseous tissue by causing a disorder in histomorphometric parameters, which were not totally reversed after 4 weeks. 6-MP administered at a dose of 5 mg/kg also caused a reduction of mineral and calcium content, mostly in the cancellous bone, which returned to normal after 4 weeks.     

Effect of concurrent administration of alendronate sodium and retinol on development of changes in histomorphometric parameters of bones induced by ovariectomy in rats

Retinol is a commonly used vitamin, especially by elderly people. Alendronate sodium, an aminobisphosphonate, is a potent antiresorptive drug used in the treatment of osteoporosis in postmenopausal women. Frequently, alendronate sodium and retinol are used concurrently. There are no reports on the interaction between alendronate sodium and retinol. The aim of the present study was to investigate the effect of concurrent administration of alendronate sodium and retinol on bone remodeling in ovariectomized rats. The histomorphometric parameters of long bones were studied. The experiments were carried out on 3-month-old Wistar rats, divided into 7 groups: I (C) - sham operated control rats, II (OVX) - ovariectomized control rats, III (OVX + ALN) - ovariectomized rats + alendronate sodium (3 mg/kg po), IV (OVX + R-1) - ovariectomized rats + retinol (700 IU/kg po), V (OVX + R-2) - ovariectomized rats + retinol (3500 IU/kg po), VI (OVX + ALN + R-1) - ovariectomized rats + alendronate sodium (3 mg/kg po) + retinol (700 IU/kg po), VII (OVX + ALN + R-2) - ovariectomized rats + alendronate sodium (3 mg/kg po) + retinol (3500 IU/kg po). The drugs were administered to the rats daily by oral gavage (alendronate sodium in the morning, retinol in the afternoon) for 28 days. Body mass gain, bone mass, mineral content in the tibia, femur and L-4 vertebra, histomorphometric parameters of the right tibia (width of osteoid, periosteal and endosteal transverse growth, area of the transverse cross section of the bone marrow cavity and the cortical bone) and the right femur (width of epiphyseal and metaphyseal trabeculae, width of epiphyseal cartilage) were studied. Bilateral ovariectomy induced osteopenic skeletal changes in mature female rats. Alendronate sodium administered at a dose of 3 mg/kg po daily inhibited the development of changes induced by ovariectomy in the skeletal system of rats. Retinol, especially administered at the dose of 3500 IU/kg daily, intensified the changes in the osseous system caused by estrogen deficiency in rats. Retinol administered concurrently with alendronate sodium attenuated the antiresorptive effect of alendronate sodium on the skeletal system in ovariectomized rats.     

Effects of alpha-escin on histomorphometrical parameters of long bones in rats with experimental post-steroid osteopenia

The excess of glucocorticosteroids leads to the development of osteopenia. A decreased bone formation rate and an increased bone resorption rate are observed. The aim of the present study was to investigate the effects of alpha-escin on the experimental prednisolone-induced osteopenia. The experiments were carried out on male Wistar rats with initial body weight of 240-310 g, divided into 4 groups (n = 6): Control, Alpha-escin, Prednisolone, Prednisolone + alpha-escin. Prednisolone (5 mg/kg im daily) and/or alpha-escin (100 mg/kg po daily) were administered for 28 days. Transverse cross-section surfaces of the cortical diaphysis and of the marrow cavity in the tibia, transverse growth, width of endosteal and periosteal osteoid, thickness of trabeculae and width of epiphyseal cartilage were examined. Prednisolone administration caused osteopenic changes in rat bones. Alpha-escin administered to the control rats did not exert statistically significant influence on the investigated bone parameters. Alpha-escin administration to prednisolone-treated rats slightly reduced the unfavorable effects of prednisolone on width of periosteal and endosteal osteoid and periosteal transverse growth in the tibia.     

Effect of administration of retinol and etidronate on bone histomorphometric parameters in ovariectomized rats

Retinol belongs to factors affecting bone remodeling. The effect of retinol on the osseous tissue depends on the dose and duration of treatment. Retinol can cause bone damage and deformation. Retinol is frequently administered chronically in too high doses, sometimes by osteoporotic patients. The aim of the present study was to examine the interaction between retinol and an antiresorptive drug--disodium etidronate in bilaterally ovariectomized rats. The experiments were carried out on Wistar rats (200 +/- 30 g), divided into 7 groups: I--sham operated control rats. II--ovariectomized control rats (OVX), III--OVX + editronate (10 mg/kg p.o.), IV--OVX + retinol (700 IU/kg p.o.). V--OVX + retinol (3500) IU/kg p.o.), VI--OVX + etidronate (10 mg/kg p.o.) + retinol (700 IU/kg p.o.), VII--OVX + etidronate (10 mg/kg p.o.) + retinol (3500 IU/kg p.o.). The drugs were administered for 4 weeks. Bone macrometric and histomorphometric parameters of the tibia (transverse growth, width of periosteal and endosteal osteoid, area of the transverse cross-section of the diaphysis and area of the transverse cross-section of the marrow cavity) and the femur (width of epiphyseal and metaphyseal trabeculae, width of epiphyseal cartilage) were examined. Editronate partially counteracted the development of changes induced by ovariectomy. Retinol (700 IU/kg p.o.) caused decreases in the area of the transverse cross-section of the marrow cavity and the width of osteoid, and an increase in the width of trabeculae. Retinol (3500 IU/kg p.o.) caused decreases in bone mass and the area of the transverse corss-section of the marrow cavity, and an increase in the width of trabecula. Concurrent administration of etidronate and retinol in ovariectomized rats seemed not to affect bone histomorphometric parameters in a way suggesting any interaction between them.     

大鼠去卵巢后对不同部位骨骼的影响

目的观察大鼠去卵巢90d后不同部位骨骼的变化特点。方法4.5月龄雌性SD大鼠20只,随机分为假手术组和去卵巢组,均灌喂5.6%乙醇5ml·kg-1·d-1,持续90d,用骨组织形态计量学方法测量胫骨上段和腰椎松质骨及胫骨中段皮质骨的动态和静态参数。结果去卵巢大鼠胫骨上段(PTM)和腰椎(LV)松质骨的骨量均减少,其中PTM骨量减少80.5%,LV骨量减少35.0%,胫骨中段(Tx)皮质骨的骨量未出现丢失,只是骨内、外膜的骨形成增加。结论大鼠去卵巢后呈现高转换型骨质疏松表现,不同部位的骨骼变化不同。     

Raloxifene does not affect the changes in bone histomorphometric parameters induced by low dose tacrolimus in male rats

Raloxifene is a selective estrogen receptor modulator. The drug reduces bone loss and prevents fractures in postmenopausal women. Tacrolimus, an immunosuppressant, is used to prevent organ transplant rejection. The effect of raloxifene and tacrolimus on the osseous bone in men has not been exhaustively determined. To study the effects of raloxifene, tacrolimus as well as concurrent administration of raloxifene and tacrolimus on the osseous tissue in male rats, a preliminary assessment of the drug action on histomorphometric parameters of rat bones was made. The experiments were carried out on mature male Wistar rats. The animals were divided into six groups, 7 animals each: I--control rats; II--rats which were administered raloxifene (5 mg/kg po daily); III-- rats which were administered tacrolimus (0.3 mk/kg po daily); IV - rats which were administered tacrolimus (0.6 mg/kg po daily; V-- rats which were administered raloxifene (5 mg/kg po daily) and tacrolimus (0.3 mg/kg po daily); VI - rats which were administered raloxifene (5 mg/kg po daily) and tacrolimus (0.6 mg/kg po daily). The drugs were administered for 4 weeks. Body mass, macrometric parameters of the tibia, femur and L-4 vertebra, histomorphometric parameters of tibia (transverse growth, width of osteoid, area of the transverse cross section of bone marrow cavity and cortical bone), and the femur (width of trabeculae, width of epiphyseal cartilage) were examined. The action of raloxifene in male rats was demonstrated through increased width of osteoid. An increased traverse growth of bone and osteoid width as well as transverse cross section of the cortical bone and the marrow cavity and increased thickness of trabeculae were observed in male rats receiving tacrolimus at 0.3 mg/kg. The administration of tacrolimus at 0.6 mg/kg resulted in increased traverse growth of bone and increased thickness of osteoid, whereas the thickness of trabeculae remained unaffected. The results obtained in the rats administered concurrently raloxifene and tacrolimus (at 0.3 mg/kg or at 0.6 mg/kg) were similar to those obtained in the group of rats receiving tacrolimus at 0.3 mg/kg. It seems that the most valuable in entire experimental system of the study are the results obtained in the group receiving tacrolimus at 0.3 mg/kg po, which are indicative of intensified bone remodeling processes with dominant the bone formation process.     

Comparative subcutaneous repeated toxicity study of enoxaparin products in rats

Enoxaparin is a low-molecular-weight heparin widely used for the prevention and treatment of thromboembolism. With the development of several enoxaparin biosimilars, real medical concerns about their safety and efficacy have been raised. This repeated dose toxicity study consists of preclinical toxicological evaluation of a biosimilar biological version of enoxaparin, the drug product “Enoxa”, compared to the enoxaparin reference drug product, “Lovenox”. Eighty white Wistar rats were treated with “Enoxa” versus the reference product, using subcutaneous therapeutic and toxic doses, varying from 3.5 to 100 mg/kg/day. Dose levels were adjusted and ultimately fixed at 3.5 and 20 mg/kg/day as therapeutic and toxic doses, respectively. A sodium chloride solution (0.9%) was used as the control, and the comparative study was conducted over periods of 14 and 28 days. Comparable effects were observed with few adverse effects at the administration dose of 20 mg/kg/day, for both enoxaparin biosimilar and reference products. Interestingly, mortality started only at high doses of 40 mg/kg/day and reached 25% at 100 mg/kg/day for both products. These results, as part of the recommended biosimilarity monitoring, demonstrated comparable toxicity profiles of “Enoxa” and “Lovenox” products in rats. Continuing investigation of biosimilarity on humans to confirm safety and efficacy is suggested.     

Effects of resistance training on bone parameters in young and mature rats

1. Osteoporosis is a major public health problem that is predicted to worsen over the next decade and preventative strategies that increase bone strength have become the focus of substantial research. 2. Although mechanical load is a primary factor in the acquisition and maintenance of skeletal tissue, the type of exercise used and when in life it is most effectively prescribed remain inconclusive. 3. The present study compared 10 weeks of resistance training in both young and mature female Sprague-Dawley rats and measured bone density and body composition by dual energy X-ray absorptiometry and biomechanical properties by three point bending tests of the tibia and femur. 4. No significant differences were observed for any of the bone parameters when comparing exercise and control groups at either age. This was despite using a comparable training protocol to that in humans and using loads of approximately 150% bodyweight. 5. The present study concludes that more intensive work programmes of resistance training or different outcome measures are required when using animal models for skeletal research.     

Effects of Cupressus sempervirens cone extract on lipid parameters in Wistar rats

BACKGROUND: Lipid-lowering drugs have been developed to treat hyperlipidemia, but they are expensive, while serious side-effects may occasionally occur. In Albania, a hydroalcoholic extract of the cones of Cupressus sempervirens is used to treat a variety of disorders, including hyperlipidemia. The purpose of our study was to assess the effects of Cupressus sempervirens cone extract (CSE) on the lipid profile of Wistar rats. MATERIALS AND METHODS: The animals were divided into two groups. Group I (30 animals) served as a control group. Serum lipid parameters, muscle and liver enzymes, red and white blood count, platelets, and serum concentrations of uric acid and creatinine were determined at baseline and at weeks 6, 12, 18 and 24 of the study. RESULTS: The oral administration of the extract resulted in a substantial decrease of serum total cholesterol, which was significant even after 6 weeks of treatment. Moreover, these animals exhibited lower total cholesterol levels compared to the controls after the initiation of treatment (p < 0.001) during the study period. The administration of the extract led to a substantial reduction in serum triglycerides (p < 0.05) in Group I, comparing 0 week to 6-24 weeks. However no significant differences in triglyceride levels were observed between CSE animals (Group I) and controls (Group II) during the entire study period. No significant changes in HDL-cholesterol in the other parameters occurred in either group. CONCLUSION: The administration of CSE has an important lipid-lowering effect in Wistar rats.     

己烯雌酚对去卵巢大鼠骨代谢影响的定量研究

目的：观察己烯雌酚对去卵巢大鼠骨质疏松的作用及机制。方法：用４．５ｍｇ·Ｌ－１的己烯雌酚按５ｍｌ·ｋｇ－１·ｄ－１ｉｇ，每周６次。１２ｗｋ后，用半自动图象数字化分析仪对大鼠胫骨近段不脱钙骨片进行骨计量学分析。结果和结论：己烯雌酚能明显抑制去卵巢引起的骨高转换，使治疗组的骨量明显高于去卵巢组（％Ｔｂ．Ａｒ＋１２２％），但未能完全防止去卵巢引起的小梁骨丢失（与对照组比较：％Ｔｂ．Ａｒ－２８％）。     

瑞舒伐他汀对格列喹酮在2型糖尿病大鼠体内药动学参数的影响

目的 探究瑞舒伐他汀对格列喹酮在2型糖尿病大鼠体内药动学参数的影响。方法 采用高糖高脂饲料喂养与ip低剂量链脲佐菌素（40 mg/kg）相结合的方法制备SD大鼠2型糖尿病模型。2型糖尿病大鼠先ig瑞舒伐他汀（10 mg/kg）,0.5 h后再ig格列喹酮（15 mg/kg）,于给药后0.5、1.5、2、2.5、4、6、8 h颈动脉取血。采用高效液相色谱法测定大鼠血浆中格列喹酮的浓度,绘制血药浓度–时间曲线,计算药动学参数。结果 在2型糖尿病大鼠中,与格列喹酮单用相比,与瑞舒伐他汀联用之后,格列喹酮的t_1/2明显延长（P＜0.01）,血浆清除率（CL）明显降低（P＜0.01）,达峰浓度（C_max）、药–时曲线下面积（AUC）明显增加（P＜0.01）。结论 瑞舒伐他汀和格列喹酮联用后,可明显改变格列喹酮在2型糖尿病大鼠体内的药动学参数,提高其血药浓度。因此,当两药联用时,应特别注意潜在的药物相互作用和格列喹酮的使用剂量。     

八厘麻毒素改造剂对麻醉大鼠的血流动力学及电生理作用

目的探讨八厘麻毒素改造剂(Rh2)对麻醉正常血压大鼠的血流动力学及电生理参数的影响。方法给予不同剂量的Rh2后,测定心脏的血流动力学及电生理参数(SAP、DAP、MAP、LVSP、LVDP、LVEDP、±dp/dtmax、HR、VRRP、VERP)。结果Rh2明显升高血压,增加左心室内压及左心室内压变化速率最大值、降低左心室终末舒张压,对心率、心电图(ECG)及心室不应期无明显影响。结论Rh2明显升高血压同时,不影响心率、ECG及心室电生理,提示其升压作用可能与增加血管外周阻力有关。     

Effects of adrenoceptor agonists and antagonists on cardiovascular functional parameters in rats.

The effects of intravenous administration of adrenoceptor agonists and antagonists on electrocardiographic or blood pressure (BP) functional parameters were assessed in urethane-anesthetized rats. The responses of cardiovascular functional parameters produced by these drugs included: (1) isoproterenol decreased the duration of a whole BP cycle (Wd), duration of the diastolic wave (Dd), peak amplitude of the systolic wave (SYa), amplitude of the diastolic notch (DNa), amplitude of the diastolic wave (DWa), pulse pressure (dp) and mean arterial pressure (mp) but increased the heart rate (HR) accompanied by prolonged R-R (RR) or P-P interval (PP) (2) propranolol decreased SYa, DNa, dp, mp, HR, the amplitude of the P wave (Pa) and amplitude of the S wave (Sa) but increased the duration of the QRS wave, P-R interval, duration of the R wave (Rd) and duration of the P wave (Pd); (3) adrenaline decreased HR (accompanied by prolonged RR and PP), Rd, Pa and amplitude of the T wave (Ta) but increased Pd, Wd, Dd, DNA, the time interval between aortic valve opening and closure (Dw), dp, mp, amplitude of the Q wave and amplitude of the R wave (Ra); (4) noradrenaline decreased HR (accompanied by prolonged RR and PP) and Pa but increased Wd, Pd, SYa, DNa, Dw, dp, mp, Ra and Ta; (5) phenylephrine decreased HR (accompanied by prolonged RR and PP) and Pa but increased Wd, Dd, DNa, mp and Ra; (6) phentolamine decreased SYa, DNa, DWa, Dw, dp and mp. This study illustrates the utility of the automated electrocardiogram (ECG) and BP analysis system for investigation of adrenoceptor agonists and antagonists. The use of this methodology not only reproduced most of cardiovascular functional parameter effects produced by these drugs using the conventional methodology but also realizes some new information about the drug-induced ECG or BP waveform effects.     

Effects of anxiolytic agents on some immunologic parameters of the stressed rats

Repeated stress under forced swim test conditions suppresses most of the immunological characteristics in rats. Diazepam and melatonin (both in a dose of 0.1 mg/kg), while not changing significantly the immunological state of intact animals, decrease the stress-induced shifts. The immunotropic effect of melatonin is much more pronounced than that of diazepam.     

Effects of different doses and schedules of diazepam treatment on lymphocyte parameters in rats

Benzodiazepines (BZD) are widely used for the treatment of anxiety. They enhance GABA-ergic neurotransmission through the binding on specific BDZ recognition sites, within the GABA_A receptor-ion channel complex. However, recent studies showed that BZD also act on peripheral benzodiazepine receptor sites (PBR) or translocator protein 18 kDa (TSPO). Evidence for a direct immunomodulatory action for BZD emerged from studies that demonstrated the presence of TSPO on immune/inflammatory cells. The present study was designed to analyze the effects of diazepam on rat lymphocyte parameters, specifically on phenotype, cell proliferation and cell death. The effects of both acute and long-term (21 days) diazepam (1 and 10 mg/kg/day) administrations were evaluated. Results showed that diazepam (1 mg/kg) treatment did not change the immune parameters analyzed. However, both diazepam (10 mg/kg) acute and long-term treatments decreased the number of apoptotic cells; they also increased the percentage of T cytotoxic cells; decreased the percentage of B cells and increased the corticosterone serum levels. The induction of functional tolerance was suggested for the highest dose of diazepam (10 mg/kg), but not for the smaller dose (1 mg/kg) used, at least for diazepam effects on corticosterone serum levels. Diazepam effects were discussed as being related to the number of TSPO sites present on immune cells and/or to the increased levels of serum corticosterone observed after the treatments used.     

Effects of BDE-99 on hormone homeostasis and biochemical parameters in adult male rats

In this study, we evaluated the effects of BDE-99 on hormone homeostasis, as well as in urinary and serum biochemical parameters of adult male rats. Animals (10 per group) received BDE-99 by gavage at single doses of 0, 0.6 and 1.2 mg/kg. Forty-five days after BDE-99 exposure, urine and serum samples were collected for hormonal and biochemical analysis. Oxidative stress (OS) markers in erythrocytes, plasma and urine were also evaluated. Urinary excretion of total protein significantly increased following BDE-99 exposure, while lactate dehydrogenase (LDH), γ-glutamil transferase (GGT), and N-acetylglucosaminidase (NAG) activities significantly decreased. Liver toxicity was evidenced by elevated serum activities of the enzymes glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT) and alkaline phosphatase (ALP). Following BDE-99 administration, OS markers in erythrocytes showed an increase in superoxide dismutase (SOD) activity, and a reduction in glutathione reductase (GR) activity. In urine, isoprostane levels increased after BDE-99 exposure. The hormonal analysis showed a significant decrease in testosterone and progesterone levels. These results support the hypothesis that BDE-99 interacts with hormonal response. Moreover, BDE-99 administration to adult male rats showed signs of renal and hepatic toxicity.