Amlodipine accelerates bone healing in a stable closed femoral fracture model in mice.

Calcium channel blockers (CCBs), which are widely used in the treatment of hypertension, have been shown to influence bone metabolism. However, there is little information on whether CCBs also influence the process of fracture healing. Therefore, the effect of the CCB amlodipine on bone healing was studied in a stable closed fracture model in mice using intramedullary screw fixation. Bone healing was investigated by radiology, biomechanics, histomorphometry and Western blot analysis 2 and 5 weeks after fracture healing. Animals were treated daily (post operatively) per os using a gavage with amlodipine low dose (1 mg/ kg body weight, n = 20), amlodipine high dose (3 mg/kg body weight, n = 20) or vehicle (NaCl) (control, n = 20) serving as a negative control. At 2 and 5 weeks, histomorphometric analysis revealed a significantly larger amount of bone tissue within the callus of amlodipine low-dose- and high-dose-treated animals when compared to controls. This was associated with a smaller amount of cartilaginous and fibrous tissue, indicating an acceleration of fracture healing. Biomechanics showed a slightly, but not significantly, higher bending stiffness in amlodipine low-dose- and high-dose-treated animals. Western blot analysis revealed a significantly increased expression of bone morphogenetic protein (BMP)-2 and vascular endothelial growth factor (VEGF). Moreover, the analysis showed a 5-fold higher expression of osteoprotegerin (OPG) and a 10-fold elevated expression of the receptor activator of NF-κB ligand (RANKL), indicating an increased bone turnover. These findings demonstrated that amlodipine accelerated fracture healing by stimulating bone formation, callus remodelling and osteoclast activity.

Production of ascorbic acid, total protein, callus and root in vitro of non-heading Chinese cabbage by tissue culture.

The objective of the present work was the selection of cultivar, suitable medium and explant type for callus, root production, ascorbic acid, total ascorbic acid, dehydroascorbic and total protein of non-heading Chinese cabbage in two cultivars 'Caixin' and 'Suzhouqing'. We compared 10 types of MS media supplemented with 0.0, 1.0, 2.0 and 3.0 mg/l TDZ; 0.0, 0.25, 0.50 and 1.0 mg/l NAA and 0.0, 5.0, 7.5 and 9.0 mg/l AgNO3 and 5 kinds of explants as embryo, leaf, root, cotyledon and hypocotyl. Maximum frequency of callus fresh weight was recorded with hypocotyl explant, which were cultured on MS + 2.0 mg/l TDZ + 1.0 mg/l NAA + 9.0 mg/l AgNO3 in 'Suzhouqing', optimum callus dry weight was obtained on the same media. The highest result for root fresh and dry weight recorded with 'Caixin' with MS + 3.0 mg/l TDZ + 1.0 mg/l NAA + 9.0 mg/l AgNO3 when we used embryo as explant. The highest ascorbic acid content was found with callus cultured on MS + 1.0 mg/l TDZ + 0.25 mg/l NAA + 5.0 mg/l AgNO3, when used leaf explant in 'Caixin' or root in 'Suzhouqing', and there were no significant difference between them. While the highest value of total AsA content was registered with callus cultured on MS + 2.0 mg/l TDZ + 0.25 mg/l NAA + 5.0 mg/l AgNO3 extracted from cotyledon in 'Caixin'. The highest content of DHA was registered with MS + 2.0 mg/l TDZ + 0.25 mg/l NAA + 5.0 mg/l AgNO3 with cotyledon in 'Caixin'. Also, in 'Caixin' MS + 3.0 mg/l TDZ + 0.25 mg/l NAA + 5.0 mg/l AgNO3 recorded the highest value of total protein content with embryo explant.

Strontium enhances BMP-2 mediated bone regeneration in a femoral murine bone defect model.

The application of strontium is one option for the clinical treatment of osteoporosis-a disease characterized by reduced bone density and quality-in order to reduce the risk of vertebral and nonvertebral fractures. Unlike other drugs used in osteoporosis therapy, strontium shows a dual effect on bone metabolism by attenuating cellular resorption and simultaneously enhancing new bone tissue formation. Current concerns regarding the systemic application of highly dosed strontium ranelate led to the development of strontium-modified scaffolds based on mineralized collagen (MCM) capable to release biologically active Sr2+ ions directly at the fracture site. In this study, we investigated the regenerative potential of these scaffolds. For in vitro investigations, human mesenchymal stromal cells were cultivated on the scaffolds for 21 days (w/ and w/o osteogenic supplements). Biochemical analysis revealed a significant promoting effect on proliferation rate and osteogenic differentiation on strontium-modified scaffolds. In vivo, scaffolds were implanted in a murine segmental bone defect model-partly additionally functionalized with the osteogenic growth factor bone morphogenetic protein 2 (BMP-2). After 6 weeks, bridging calluses were obtained in BMP-2 functionalized scaffolds; the quality of the newly formed bone tissue by means of morphological scores was clearly enhanced in strontium-modified scaffolds. Histological analysis revealed increased numbers of osteoblasts and blood vessels, decreased numbers of osteoclasts, and significantly enhanced mechanical properties. These results indicate that the combined release of Sr2+ ions and BMP-2 from the biomimetic scaffolds is a promising strategy to enhance bone regeneration, especially in patients suffering from osteoporosis. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:174-182, 2020.

Alcohol-related deficient fracture healing is associated with activation of FoxO transcription factors in mice.

The process of fracture healing is complex, and poor or incomplete healing remains a significant health problem. Proper fracture healing relies upon resident mesenchymal stem cell (MSC) differentiation into chondrocytes and osteoblasts, which are necessary for callus formation and ossification. Alcohol abuse is a leading contributor to poor fracture healing. Although the mechanism behind this action is unknown, excessive alcohol consumption is known to promote systemic oxidative stress. The family of FoxO transcription factors is activated by oxidative stress, and FoxO activation antagonizes Wnt signaling, which regulates mesenchymal stem cell differentiation. We hypothesize that alcohol exposure increases oxidative stress leading to deficient fracture repair by activating FoxO transcription factors within the fracture callus which disrupts chondrogenesis of mesenchymal stem cells. Our laboratory has developed an experimental model of delayed fracture union in mice using ethanol administration. We have found that ethanol administration significantly decreases external, cartilaginous callus formation, and hallmarks of endochondral ossification, and these changes are concomitant with increases in FoxO expression and markers of activation in fracture callus tissue of these mice. We were able to prevent these alcohol-induced effects with the administration of the antioxidant n-acetyl cysteine (NAC), suggesting that alcohol-induced oxidative stress produces the perturbed endochondral ossification and FoxO expression. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2106-2115, 2016.

Differential Effects of Thidiazuron on Production of Anticancer Phenolic Compounds in Callus Cultures of Fagonia indica.

Fagonia indica, a very important anticancer plant, has been less explored for its in vitro potential. This is the first report on thidiazuron (TDZ)-mediated callogenesis and elicitation of commercially important phenolic compounds. Among the five different plant growth regulators tested, TDZ induced comparatively higher fresh biomass, 51.0 g/100 mL and 40.50 g/100 mL for stem and leaf explants, respectively, after 6 weeks of culture time. Maximum total phenolic content (202.8 µg gallic acid equivalent [GAE]/mL for stem-derived callus and 161.3 µg GAE/mL for leaf-derived callus) and total flavonoid content (191.03 µg quercetin equivalent [QE]/mL for stem-derived callus and 164.83 µg QE/mL for leaf-derived callus) were observed in the optimized callus cultures. The high-performance liquid chromatography (HPLC) data indicated higher amounts of commercially important anticancer secondary metabolites such as gallic acid (125.10 ± 5.01 µg/mL), myricetin (32.5 ± 2.05 µg/mL), caffeic acid (12.5 ± 0.52 µg/mL), catechin (9.4 ± 1.2 µg/mL), and apigenin (3.8 ± 0.45 µg/mL). Owing to the greater phenolic content, a better 2-2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity (69.45 % for stem explant and 63.68 % for leaf explant) was observed in optimized calluses. The unusually higher biomass and the enhanced amount of phenolic compounds as a result of lower amounts of TDZ highlight the importance of this multipotent hormone as elicitor in callus cultures of F. indica.

Impact of 4-methylbenzylidene camphor, daidzein, and estrogen on intact and osteotomized bone in osteopenic rats.

The study investigated the influence of 4-methylbenzylidene camphor (4-MBC), daidzein, and estradiol-17ß-benzoate (E(2)) on either intact or osteotomized cancellous bone in ovariectomized (Ovx) rats. Three-month old Ovx rats were fed with soy-free (SF) diet over 8 weeks; thereafter, bilateral transverse metaphyseal osteotomy of tibia was performed and rats were divided into groups: rats fed with SF diet and SF diet supplemented with 4-MBC (200 mg), daidzein (50 mg), or E(2) (0.4 mg) per kilogram body weight. After 5 or 10 weeks, computed tomographical, biomechanical, histological, and ashing analyses were performed in lumbar spine and tibia of 12 rats from each group. 4-MBC and E(2) improved bone parameters in lumbar spine and tibia, were not favorable for osteotomy healing, and decreased serum osteocalcin level. However, daidzein improved bone parameters to a lesser extent and facilitated osteotomy healing. For lumbar spine, the bone mineral density was 338±9, 346±5, 361±6, and 360±5 mg/cm(3) in SF, daidzein, 4-MBC, and E(2), respectively, after 10 weeks. For tibia, the yield load was 98±5, 114±3, 90±2, and 52±4 N in SF, daidzein, 4-MBC, and E(2), respectively, after 10 weeks. Serum daidzein was 54±6 ng/ml in daidzein group and equol was not detected. Alp and Igf1 genes were down-regulated in callus after daidzein and E(2) compared with 4-MBC (week 5). The response of bone tissue and serum markers of bone metabolism could be ordered: daidzein<4-MBC

BMP-7 in combination with estrogen enhances bone formation in a fracture callus explant culture.

In postmenopausal women, estrogen withdrawal results in decrease in bone density or osteoporosis. Osteoporosis leads to fracture and retards bone-healing response. Bone morphogenetic protein-7 (BMP-7), a member of the transforming-growth factor-beta superfamily, has been shown as a promising candidate that stimulates bone growth in its application to fracture healing. The purpose of this study was to determine whether BMP-7 could enhance bone formation in the absence of estrogen. Female rats underwent a controlled closed fracture at the midshaft of the right femur. The callus tissues were harvested from the fracture site eight days following the fracture, and were cultured in serum-free media. The explanted callus tissues were then treated with BMP-7, estrogen (E2) or both. We assessed bone formation by measuring alkaline phosphatase (AP) activity, expression of an osteogenic transcription factor, Runt-related transcription factor-2 (Runx2), production of nitric oxide (NO), and calcium mineralization. Supplementation of serum-free cultures with BMP-7 alone increased cell proliferation by twofold, caused a 6.5-fold increase in AP activity, and enhanced calcium mineralization after 48 h. Moreover, BMP-7 in combination with E2 caused a 8.2-fold increase in the AP activity. Runx2 protein expression was increased following stimulation with BMP-7 and E2. Interestingly, E2 induced the amount of NO production by twofold, whereas BMP-7 did not, either alone or with E2. Thus, BMP-7 could enhance early and late markers of bone fracture healing in callus explant cultures, except for NO. BMP-7 could be a promising growth factor in the treatment of fractures as a consequence of osteoporosis.

Formononetin promotes early fracture healing through stimulating angiogenesis by up-regulating VEGFR-2/Flk-1 in a rat fracture model.

Plant-derived phytoestrogens have bone protective effects, but the molecular mechanism behind these effects remains unclear. This study is aimed at fully characterizing the fracture healing process of formononetin, and investigating the mechanism underlying angiogenesis in calluses of a rat fracture model. Femoral fractures were produced in 2-month-old Sprague-Dawley rats. A 20 microg/kg or 200 microg/kg dose of formononetin was orally administrated once a day during the healing period of 21 days. The results showed that in the early stage of chondrogenesis (days 3), formononetin significantly increased the number of vessels, and expression of vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR-2/flk-1) compared with control. However, the larger dose of formononetin had no significant difference on expression of VEGF and VEGFR-2/Flk-1 compared with that of the smaller dose of formononetin. After 7 days of administration, formononetin markedly induced differentiation of mesenchymal stem cells in the fracture site. After 14 days, gene expression of mesenchymal progenitors such as alkaline phosphatase (ALP), osteocalcin (OCN), osteopontin (OPN) and collagen type I (Col I), indicating osteogenic differentiation, was markedly stimulated by formononetin compared with control. These results suggest that formononetin promotes early fracture healing through angiogenesis activation in the early stage of fracture repair, and osteogenesis acceleration in the later stages, and thus may be beneficial for fracture healing.

[Effects of acupuncture on the expression of brain-derived neurotrophic factor in the ovariectomized rat fracture model].

OBJECTIVE: To observe the effect of acupuncture on fracture in the ovariectomized rat and the mechanism. METHODS: Sixty SD female rats were randomly divided into 4 groups: normal group (group A), model group (group B), acupuncture group (group C) and Nilestriol group (group D). In all the groups, except the group A which received sham operation, the rats were overiectomized for preparing the osteoporosis model. Three months after the ovariectomy, the left femurs of the rats were closely fractured. Then, the group A and B were treated with oral administration of normal saline solution, 3 mL, weekly. The rats in the group C were treated daily with acupuncture at "Huantiao"(GB 30), "Housanli" (ST 36), "Yanglingquan"(GB 34) and "Weizhong"(BL 40) on the left hind legs; the rats in the group D were given orally Nilestriol solution (0.2 mg/mL) in a dose of 0.6 mL/100 g body weight, weekly. At the 7th, 14th, 21st and 28th days, some rats were sacrificed and their fractural callus and blood samples were taken for histological examinations and immunohistochemical examination of brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB). RESULTS: HE stained callus slides observed by optical microscope showed that the process of fracture healing in the group A, C, D was faster than that in the group B. Positive immuno-stalning of BDNF and TrkB could be seen in the all groups, mainly on the 7 and 14 days after the fracture. The expression levels from high to low in turn were group A, C, D and B. CONCLUSION: Expressions of BDNF and TrkB in callus of osteoporotic fracture were less than that of the normal fracture; acupuncture can elevate the expression levels and accelerate the process of fracture healing.

[Effects on VEGF and VEGF mRNA expression in issues of callus in treating fracture of rabbit with three-period treatment theory of bone fracture in traditional Chinese medicine].

OBJECTIVE: To observe the effects of the three-period treatment theory of bone fracture in traditional Chinese medicine (TCM) on VEGF and VEGF mRNA expression in the issues of callus of rabbits. And to explore the rationality of phasing method in TCM in treating fracture. METHOD: one hundred and forty male and healthy rabbits were made 3 mm wide bone defection at lower one third part of both radius as fracture healing model. Then those rabbits were divided into four groups randomly, which are three-period treatment group (TTG), one-period treatment group (OTG), positive medicine treatment group (PTG) and model control group (MCG). Those rabbits in TTG were treated with three-period treatment. Those in OTG were treated with one-period treatment. Those in PTG were feed by guzhecuoshangsan, a Chinese patent medicine which is used to treat bone fracture. Those in model control group were given no prescription or drug but distilled water as same dose as that of other groups. At day 3, 6, 9, 14, 28, 42 and 56, five rabbits were selected from every group randomly and were killed by aeroembolism respectively. Their radius were taken out and the left one was taken as the research object. Immunohistochemistry stain and in situ hybridization stain were performed to examinate the VEGF and VEGF mRNA expression in the haematoma, fibrous callus and soft callus. RESULT: All TCM treatment groups can enhance the VEGF and VEGF mRNA expression in the haematoma, fibrous callus and soft callus at different time points in fracture healing. The VEGF and VEGF mRNA expression in the three issues of TTG had the tendency of higher than that of the other groups at the most time points after operation. CONCLUSION: TCM can promote the VEGF and VEGF mRNA expression in the haematoma, fibrous callus and soft callus. Different Chinese medicines play various roles on VEGF and VEGF mRNA expression at different stage of fracture healing. Treating fracture in three-period treatment has more predominant effect on the expression of VEGF and VEGF mRNA in the haematoma, fibrous callus and soft callus than that of treating fracture with single prescription or drug. It is necessary to treat fracture in stages.

Neuromuscular electrical stimulation enhances fracture healing: results of an animal model.

Neuromuscular electrical stimulation (NMES) could simulate physiological muscle functions known to be associated with the normal bone healing process. The object of the present study was to evaluate the effect of NMES on fracture healing, using an animal model. Thirty rabbits received unilateral, transverse, mid-tibial, 3-mm gapped osteotomies that were stabilized with double-bar external fixators. The femoral vein was ligated to induce venous stasis. From the fourth post-operative day, the study group was treated with 1 h daily of NMES for four weeks, while the control group was treated without NMES. For NMES, two surface electrodes were used: one above the patellar tendon and another around the lateral thigh. Callus area and mineral content at the osteotomy gap were measured, biweekly, using computerized tomographic examinations. Biomechanical properties of healing were evaluated with a torsion test, eight weeks after the index operation. Osteotomies treated with NMES exhibited 31% (p=0.01) higher mineral content and 27% (p=0.009) larger callus area than control osteotomies at eight weeks. The maximum torque, torsional stiffness, angular displacement at maximum torque, and energy required to failure of specimens in the study group were 62% (p=0.006), 29% (p=0.03), 34.6% (p=0.008), and 124% (p<0.0001) higher, respectively, than those in the control group at eight weeks. The results of the present study demonstrated that the use of NMES can enhance callus development and mineralization, with the consequent improvement in biomechanical properties of the healing bone.

Effects of receptor activator of NFkappaB (RANK) signaling blockade on fracture healing.

As dominant regulators of osteoclastogenesis and bone resorption, receptor activator of NFkappaB (RANK), receptor activator of NFkappaB ligand, and OPG have been identified as ideal drug targets for the treatment of metabolic bone disease. One concern regarding the therapeutic use of RANK signaling inhibitors is their effect on fracture healing. Therefore we tested if uncoupling and osteoclast depletion via RANK blockade affects callus formation, maturation and matrix remodeling, as well as union rates in a mouse tibia fracture model. Low dose (1 mg/kg i.p.) RANK:Fc therapy had no effect on callus formation, matrix maturation and remodeling, and resulted in 100% bony union by day 28. High dose RANK:Fc treatment (10 mg/kg i.p.) effectively eliminated osteoclasts at the fracture site on day 14, with no significant effects on fracture healing. When therapy was discontinued, normal numbers of osteoclasts were observed at the fracture site by day 28. However, continuous therapy resulted in a large osteopetrotic callus consisting of both mineralized and unmineralized matrix that was void of osteoclasts, but bony union was unaffected at day 28. We also evaluated this process in the complete absence of RANK signaling using RANK -/- mice. These animals exhibited significant radiographic and histologic evidence of callus formation, indicating that RANK signaling is not required for fracture callus formation. However, only 33% of RANK -/- animals formed bony unions compared to 100% of the osteopetrotic control mice. This defect was most likely a result of decreased blood flow, as evidenced by fewer blood vessels in the RANK -/- animals. Together, these data imply that osteoclast depletion via inhibition of RANK signaling is a viable option for the treatment of pathological bone loss since no adverse effects on fracture healing are observed when therapy is discontinued.

Differences in mandibular distraction osteogenesis after corticotomy and osteotomy.

Corticotomy or osteotomy was performed on opposing sides of the mandibles in 18 goats. A custom-made distractor was used to lengthen the mandible at a rate of 1 mm/day for 10 days (total 10 mm elongation). Six goats were sacrificed respectively at 2, 4 and 8 weeks after completion of distraction. The distracted calluses were harvested and processed for radiographic, histologic, and scanning electron microscopic evaluation as well as Ca/P ratio analysis. The regenerate bone in the corticotomy side showed more bone formation and earlier mineralization than in the osteotomy side. The results of this study suggest that preservation of intramedullary vessels is beneficial to bone regeneration following mandibular osteodistraction, and that performing corticotomy may be a simple but effective way to promote the maturity of the distracted callus and shorten the time for fixation.

[The effect of wumingyi chongji on BMP content in callus].

A kind of Chinese herb medicine--Wumingyi chongji could promote fracture healing had been proved. In order to disclose the mechanism, a standard fracture model was produced in 50 healthy male Newzealand rabbits. The animals were randomly divided into experimental group and control group. Another 5 rabbits without operation act as nomal. By immunohistochemical study, the bone morphogenetic protein (BMP) content in callus was calculated by computerized interacive morphometry (CIM) in the 1st, 2nd, 3rd, 4th, 5th week after fracture. The results were: BMP in callus was much more than in nomal (P < 0.01); BMP in callus increased from the 1st week to the 3rd week, decreased from 4th week to 5th week, and was more in experimental group in the 1st and 2nd week than in the control group (P < 0.01). The highest BMP content appeared in the 2nd week in the experimental group, while in the 3rd week in the control group. It was concluded that Wumingyi chongji could promote osteoblast to synthetize BMP, BMP induce preosteoblast change into osteoblast. Thus the rate of fracture healing could be increased.

[Effect of radix Salviae miltiorrhizae on calcium, zinc, copper content in serum, callus and bony tissue in early stage of healing process in rat closed tibial fracture].

Changes of calcium, zinc, copper contents in serum, callus and bony tissue in the early stage of the healing process of rat closed tibial fracture, also the changes of them with radix Salviae miltiorrhizae (RSM) treatment were studied. It was found that calcium, zinc contents and Zn/Cu ratio increased significantly and the rise of serum copper content was inhibited by the administration of RSM after fracture. Zn/Cu ratio in fracture callus was correlated to the calcium content in fracture callus. These findings suggested that the effect of the promotion of RSM on fracture healing was related to the increased zinc content in serum, also related to the acceleration of mobilization of zinc in fractured bone, and to the acceleration of fracture callus formation and mineralization process by the increased zinc and Zn/Cu ratio in the callus of the fracture.

Energy metabolism in fracture healing. Measurement of adenosine triphosphate in callus to monitor progress.

We measured the adenosine triphosphate (ATP) content of callus at various intervals during healing in 78 fractured tibiae in 10- to 12-week-old rabbits. The results, compared with the level in normal tissues, showed a high rate of energy metabolism in the early phase of fracture healing, which persisted until the callus was corticalised and remodelling had started. The ATP content could provide a more sensitive index to monitor fracture healing in animal studies. Our findings lend support to the need for nutritional supplements for patients with multiple fractures.

[Effect of vitamin D3 and its metabolites 1,25-dihydroxycholecalciferol and 24,25-dihydroxycholecalciferol on callus mineralization in rats with femoral fracture]. / Vliianie vitamina D3 i ego metabolitov--1,25-dioksikholekal'tsiferola i 24,25-dioksikholekal'tsiferola--na mineralizatsiiu kostnoi mozoli u krys s perelomom bedra.

Additional administration of vitamin D3 at a physiological dose of 0.25 microgram daily into rats with femur fracture within 4 weeks did not affect the specific weight and chemical composition (content of Ca2+, P) in diaphyses of intact and impaired femurs as well as the content of Ca2+. Pi and activity of alkaline phosphatase in blood serum of the animals. At a higher dose 2.5 microgram daily vitamin D3 increased concentration of Pi in blood serum but did not alter the other parameters studied. Physiological doses of 1,25-dihydroxycholecalciferol (1.25 (OH)2D3) and 24,25-dihydroxycholecalciferol (24,25 (OH)2D3) (00.3 microgram and 0.25 microgram daily, respectively) did not affect the specific weight and composition of the impaired diaphyses, content of Ca2+ and activity of alkaline phosphatase in blood but increased slightly the Pi concentration. After a 5-fold increase in the dose of 1,25(OH)2D3 (0.15 microgram daily) specific weight and content of Ca2+ were decreased in the impaired bones with simultaneous increase in concentration of Ca2+, Pi and activity of alkaline phosphatase in blood serum. These data suggest that reparation was impaired under the conditions of acceleration of the bone tissue resorption. Increased doses of 24, 25(OH)2D3 (1.25 micrograms daily) stimulated the increase in specific weight and mineralization of the impaired bones and normalized the increased alkaline phosphatase activity in blood serum. Clinical examination of 24,25(OH)2D3 could be recommended as a drug stimulating the reparation under conditions of bone fracture.

[Effect of carbostimulin and its mixture with vitamin D3 on the mineralization process of the bone callus in rabbits]. / Vliianie karbostimulina i smesi ego s vitaminom D3 na protsess mineralizatsii kostnoi mozoli krolikov.

Mineralization of rabbit bone callus was studied within 15 days after resection of the upper part of radius bone inder conditions of treatment with carbostimuline and its mixture with vitamin D3. Content of calcium in the bone regenerate was increased by 40.8% after administration of carbostimuline and--by 70.5% after treatment with mixture containing vitamin D3. These preparations caused only slight effects on the phosphorus content. Dry residue in the regenerate os f animals, treated with the preparations, was increased approximately 2-fold (43% and 23%, respectively, p less than or equal to 0.001) as compared with control group. Content of citric acid was distinctly higher in the bone tissue of the treated animals. Within 15 days after the operation content of sialic acids wanormalized in blood serum of the animals. The data obtained were corroborated by X-ray and histologic examinations.

[Mechanism of the stimulating effect of an electric current on reparative regeneration of bone tissue]. / K voprosu o mekhanizme stimuliruiushchego deistviia élektricheskogo toka na reparativnuiu regneratsiiu kostnoi tkani.

Experiments were conducted on rabbits. Changes in ATP in the regenerating bone tissue after incomplete osteotomy and removal of a bone section, and also in cases of reparative osteogenesis stimulation in the region of the bone defect by means of pulse electric current were studied. ATP content in the bone callus after incomplete osteotomy and electrostimulation proved to exceed such in the regenerating bone tissue following removal of the bone fragment when no stimulation was applied. On the basis of the data obtained it is suggested that improvement of energy provision of the fracture consolidation process was one of the important links in the mechanism of stimulating influence of the electric current on the reparative regeneration of the bone tissue.