The retina of SD rats was incubated in four types of the Eagle solution respectively. The results showed the cAMP level of retinas was the lowest in the hGnMg(high glucose with normal magnesium) solution but the cAMP level was significantly increased in the hGhMg(high glucose with high magnesium) and higher than that of normal control group. The cAMP level was the highest in the nGhMg(normal glucose with high magnesium). The results suggested that magnesium might play an important role in maintaining the normal metabolism of glucose of the retinal tissue. （Chin J Ocul Fundus Dis,1992,8:138-140）
Eighteen SD rats with streptozotocin-induced diabetes were observed for the influence of magnesium in glycolytic pathway in their retinal tissue.The diabetic rats were divided into 3 groups:6 of them drank 0.5% Mgso4 solution every day,6 received intramuscular Mgso4 (0.05/kg)in half month interval,and the another 6 drank tape water every day.Six normal rats were employed as employed as nondiabetic control.The activity of the three crucial rate-limiting enzymes ralating to glycolytic pathway-hexokinase,phosphofructokinase and pyruvate kinase in retinal tissue of the rats was investigated after a period of 30days.The results revealed that the levels of the enzymes were significantly depressed in diabetic rats not taking magnesium,while the enzyme levels maintained nearly the same in diabetic rats taking magnesium,while the enzyme levels maintained nearly the same in diabetic rats taking magnesium as in the control group.This suggested that the glycolytic pathway in retinal tissue was disturbed in early stage of diabtes,and magnesium might play an important role in maintaining the normal metabolism of glucose. （Chin J Ocul Fundus Dis,1993,9:81-83）
Objective To evaluate the effect of biodegradable magnesium alloy materials in promoting tendon-bone healing during rotator cuff tear repair and to investigate their potential underlying biological mechanisms.Methods Forty-eight 8-week-old Sprague Dawley rats were taken and randomly divided into groups A, B, and C. Rotator cuff tear models were created and repaired using magnesium alloy sutures in group A and Vicryl Plus 4-0 absorbable sutures in group B, while only subcutaneous incisions and sutures were performed in group C. Organ samples of groups A and B were taken for HE staining at 1 and 2 weeks after operation to evaluate the safety of magnesium alloy, and specimens from the supraspinatus tendon and proximal humerus were harvested at 2, 4, 8, and 12 weeks after operation. The specimens were observed macroscopically at 4 and 12 weeks after operation. Biomechanical tests were performed at 4, 8, and 12 weeks to test the ultimate load and stiffness of the healing sites in groups A and B. At 2, 4, and 12 weeks, the specimens were subjected to the following tests: Micro-CT to evaluate the formation of bone tunnels in groups A and B, HE staining and Masson staining to observe the regeneration of fibrocartilage at the tendon-bone interface after decalcification and sectioning, and Goldner trichrome staining to evaluate the calcification. Immunohistochemical staining was performed to detect the expressions of angiogenic factors, including vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2), as well as osteogenic factors at the tendon-bone interface. Additionally, immunofluorescence staining was used to examine the expressions of Arginase 1 and Integrin beta-2 to assess M1 and M2 macrophage polarization at the tendon-bone interface. The role of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway in tendon-bone healing was further analyzed using real-time fluorescence quantitative PCR. Results Analysis of visceral sections revealed that magnesium ions released during the degradation of magnesium alloys did not cause significant toxic effects on organs such as the heart, liver, spleen, lungs, and kidneys, indicating good biosafety. Histological analysis further demonstrated that fibrocartilage regeneration at the tendon-bone interface in group A occurred earlier, and the amount of fibrocartilage was significantly greater compared to group B, suggesting a positive effect of magnesium alloy material on tendon-bone interface repair. Additionally, Micro-CT analysis results revealed that bone tunnel formation occurred more rapidly in group A compared to group B, further supporting the beneficial effect of magnesium alloy on bone healing. Biomechanical testing showed that the ultimate load in group A was consistently higher than in group B, and the stiffness of group A was also greater than that of group B at 4 weeks, indicating stronger tissue-carrying capacity following tendon-bone interface repair and highlighting the potential of magnesium alloy in enhancing tendon-bone healing. Immunohistochemical staining results indicated that the expressions of VEGF and BMP-2 were significantly upregulated during the early stages of healing, suggesting that magnesium alloy effectively promoted angiogenesis and bone formation, thereby accelerating the tendon-bone healing process. Immunofluorescence staining further revealed that magnesium ions exerted significant anti-inflammatory effects by regulating macrophage polarization, promoting their shift toward the M2 phenotype. Real-time fluorescence quantitative PCR results demonstrated that magnesium ions could facilitate tendon-bone healing by modulating the PI3K/AKT signaling pathway. ConclusionBiodegradable magnesium alloy material accelerated fibrocartilage regeneration and calcification at the tendon-bone interface in rat rotator cuff tear repair by regulating the PI3K/AKT signaling pathway, thereby significantly enhancing tendon-bone healing.
Objective To investigate the effect of magnesium phosphate cement (MPC) to fix fractures.Methods In vitro: fifty four pairs of fresh pig femoral heads were made 1 cm2 fracture and divided into 6 groups(n=9 pairs ). MPC was used to agglutinate fracture of femoral headsat 100% humidity and at 25℃, 37℃ respectively. At 30 minutes, 2 and 24hours after agglutination, the biomechanical strength was measured. In vivo:the tibia plateau fracture models on both sides of 24 rabbits were made, one side was fixed with “L” shaped plate, and the other side was fixed with MPC. Then the effect of treatment was investigated by macrography, micrography, radiography and the changes of serum electrolyte levels at 3 days, 3，6 and 9 weeks after operation. Results In vitro: the adhesive ability of MPCwas b. At 24 hours after MPC agglutination, the average tensile strength was 117.16±23.29 N/cm2. In vivo:after 6 weeks of fixation, the X-ray results showed that all rabbits’ tibia plateau fractures were healed without displacement, and MPC was absorbed gradually. The changes ofserum electrolyte levels were very minimal. The macrography observation showed that reduction of fracture were good at 3 days after operation, partial MPC remained in fracture end at 3 weeks, fracture line disappeared at 6 weeks and good remodeling was achieved at 9 weeks after operation in the experimental group. Themicrography observation showed that the interface between bone and MPC was distinct at 3 days, MPC was degraded gradually and trabeculae began to grow into MPCat 3 weeks, and almost all MPC was degraded at 6 and 9 weeks of operation. Conclusion MPC is a promising biomaterial, and might potentially be used for fracture treatment.
Objective To research in vitro biocompatibility of silicon containing micro-arc oxidation (MAO) coated magnesium alloy ZK60 with osteoblasts. Methods The surface microstructure of silicon containing MAO coated magnesium alloy ZK60 was observed by a scanning electron microscopy (SEM), and chemical composition of the coating surface was determined by energy dispersive spectrum analysis. The experiments were divided into 4 groups: silicon containing MAO coated magnesium alloy ZK60 group (group A), uncoated magnesium alloy ZK60 group (group B), titanium alloy group (group C), and negative control group (group D). Extracts were prepared respectively with the surface area to extraction medium ratio (1.25 cm2/ mL) according to ISO 10993-12 standard in groups A, B, and C, and were used to culture osteoblasts MC3T3-E1. The α-MEM medium supplemented with 10% fetal bovine serum was used as negative control in group D. The cell morphology was observed by inverted phase contrast microscopy. MTT assay was used to determine the cell viability. The activity of alkaline phosphatase (ALP) was detected. Cell attachment morphology on the surface of different samples was observed by SEM. The capability of protein adsorption of the coating surface was assayed, then DAPI and calcein-AM/ethidium homodimer 1 (calcein-AM/EthD-1) staining were carried out to observe cell adhesion and growth status. Results The surface characterization showed a rough and porous layer with major composition of Mg, O, and Si on the surface of silicon containing MAO coated magnesium alloy ZK60 by SEM. After cultured with the extract, cells grew well and presented good shape in all groups by inverted phase contrast microscopy, group A was even better than the other groups. At 5 days, MTT assay showed that group A presented a higher cell proliferation than the other groups (P lt; 0.05). Osteoblasts in groups A and C presented a better cell extension than group B under SEM, and group A exhibited better cell adhesion and affinity. Protein adsorption in group A [ (152.7 ± 6.3) μg/mL] was significantly higher than that of group B [(96.3 ± 3.9) μg/mL] and group C [ (96.1 ± 8.7) μg/mL] (P lt; 0.05). At each time point, the adherent cells on the sample surface of group A were significantly more than those of groups B and C (P lt; 0.05). The calcein-AM/EthD-1 staining showed that groups A and C presented better cell adhesion and growth status than group B. The ALP activities in groups A and B were 15.55 ± 0.29 and 13.75 ± 0.44 respectively, which were significantly higher than those in group C (10.43 ± 0.79) and group D (10.73 ± 0.47) (P lt; 0.05), and group A was significantly higher than group B (P lt; 0.05). Conclusion The silicon containing MAO coated magnesium alloy ZK60 has obvious promoting effects on the proliferation, adhesion, and differentiation of osteoblasts, showing a good biocompatibility, so it might be an ideal surface modification method on magnesium alloys.
ObjectiveTo explore the effects of postoperative magnesium sulphate on pain relief after open gynecological surgery. MethodsSixty women who were diagnosed as hysteromyoma in Lucheng People' Hospital in Wenzhou city and underwent open hysterectomy from July 2011 to May 2012 were randomly divided into two groups (30 women in each group). Applying epidural administration of magnesium sulfate, the magnesium sulfate group (n=30) was given 500 μg magnesium sulfate and 1 mg morphine, while the control group (n=30) was only given 1 mg morphine. Pain scores (at 2 h, 4 h, 8 h, 16 h and 24 h, respectively) as well as complications were observed. Plasma levels of β-endorphin (β-EP) (in 4 h and 24 h, respectively) and the first time when needs postoperative analgesia were recorded. ResultsCompared with the control group, pain scores during 24 h after operation, levels of β-EP at 4 h and 24 h, and the first time for postoperative analgesia were better improved in the magnesium sulfate group. ConclusionEpidural administration of magnesium sulfate combined with morphine is an effective and safe method to improve the effects of postoperative magnesium sulphate on pain relief after open gynecological surgery.
Objective To review the research progress of magnesium and magnesium alloy implants in the repair and reconstruction of sports injury. Methods Relevant literature of magnesium and magnesium alloys for sports injury repair and reconstruction was extensively reviewed. The characteristics of magnesium and its alloys and their applications in the repair and reconstruction of sports injuries across various anatomical sites were thoroughly discussed and summarized. Results Magnesium and magnesium alloys have advantages in mechanical properties, biosafety, and promoting tendon-bone interface healing. Many preclinical studies on magnesium and magnesium alloy implants for repairing and reconstructing sports injuries have yielded promising results. However, successful clinical translation still requires addressing issues related to mechanical strength and degradation behavior, where alloying and surface treatments offer feasible solutions. Conclusion The clinical translation of magnesium and magnesium alloy implants for repairing and reconstructing sports injuries holds promise. Subsequent efforts should focus on optimizing the mechanical strength and degradation behavior of magnesium and magnesium alloy implants. Conducting larger-scale biocompatibility testing and developing novel magnesium-containing implants represent new directions for future research.
Objective To investigate the differences in characteristics and susceptibility factors between infectious stones and calcium oxalate stones, and provide reference value for screening infectious stones in clinical work. Methods According to the results of analysis of stone components in the extracorporeal shock wave lithotripsy center of West China Hospital of Sichuan University between June 2014 and April 2017, 392 patients with infectious stones (including 56 patients with magnesium ammonium phosphate stones in group A and 336 patients with calcium carbonate apatite in group B) and 392 patients with calcium oxalate stone (group C) were selected to discuss the difference of clinical features by retrospectively analyzing the clinical data. Results The proportion of females, the long diameter of stones and the proportion of staghorn stones in group A [75.0%, (3.9±2.5) cm, 41.1%] were higher than those in group B [39.3%, (2.4±1.3) cm, 6.0%], and the proportion of females and the long diameter of stones in group A and B were larger than those in group C [30.1%, (1.9±0.7) cm]; the differences above were statistically significant (P<0.05). There was no significant difference among the three groups in surgically history or complicated factors of urinary tract such as ureteral stricture (P>0.05). The prevalences of diabetes, renal tubular acidosis and hyperlipidemia in patients with infectious stones were higher than those in group C. The prevalences of renal tubular acidosis and hyperlipidemia in group A (16.1%, 39.3%) were higher than those in group B (0.6%, 21.1%), the positive rate of urine culture in group A (58.9%) was higher than that in group B (20.5%), which were both higher than that in group C (8.9%); these differences were statistically significant (P<0.017). The bacteria cultured from urine were mainlyProteus mirabilis and Escherichia coli in group A, and Escherichia coli in group B and group C. Conclusion Patients with large volume of stones, complicated with diabetes, renal tubular acidosis, hyperlipidemia and positive urine culture are more likely to have infectious stones.
Tweenty-one SD rats with streptozotocin-induced diabetes were investigated for the influence of magnesium in cAMP level in the retina of the diabetic rats. The diabetic rats were divided into 3 groups: group 1, drinking tap hehwater; group 2, drinking 0.5% MgSO4 solution and group 3, receiving intramuscular MgSO4(0.1g/kg) once a month. In addition, group 4, a controlgroup of normal nondiabetic rats fed with tap water. In aperiod of 5 months examination, the growth and health conditions of diabetic rats were found to be nearly normal in group 2, 3 and 4, manifested by gaining weight and soft, smooth hairs on the skin, in contrast with loss in weight, rough hairs and even dying of infection in 2 of the diabetic rats in group 1. furthermore, the level of cAMP content in retina was found significantly higher in the diabetic rats taking Mg++ in spite of the route of administration(group 2, 3), as well as in the control group(group 4) than that of the diabetic rats which were fed with tap water. These results demonstrated that Mg++ might play an important role in improving the metabolism of diabetic rats including the retinal tissue by influencing the level of cAMP content, which is necessary in nuclear acid metabolism, protein synthesis, proliferation and differentiation, and other intracellular metabolic processes. （Chin J Ocul Fundus Dis,1992,8:141-143）
Objective To systematically evaluate the effects of magnesium sulfate on postoperative pain and complications after general anesthesia. Methods A literature search was conducted in following databases as The Cochrane Library, EMbase, PubMed, EBSCO, Springer, Ovid, CNKI and CBM from the date of establishment to September 2011 to identify randomized controlled trials (RCTs) about intravenous infusion of magnesium sulfate during general anesthesia. All included RCTs were assessed and the data were extracted according to the standard of Cochrane systematic review. The homogenous studies were pooled using RevMan 5.1 software. Results A total of 11 RCTs involving 905 patients were included. The results of meta-analyses showed that compared with the control group, intravenous infusion of magnesium sulfate during general anesthesia significantly reduced the visual analog scale (VAS) scores at the time-points of 2, 4, 6, 8, 16, and 24 hours, respectively, after surgery, the postoperative 24 hours morphine requirements, and the incidents of postoperative nausea and vomiting (RR=0.61, 95%CI 0.40 to 0.91, P=0.02) and chilling (RR=0.29, 95%CI 0.14 to 0.59, P=0.000 7). Although the incidents of bradycardia (RR=1.93, 95%CI 1.05 to 3.53, P=0.03) increased, there were no adverse events or significant differences in the incidents of hypotension and serum concentration changes of magnesium. Conclusion Intravenous infusion of magnesium sulfate during general anesthesia may obviously decrease the pain intensity, and the incidents of nausea and vomiting and chilling after surgery, without increasing cardiovascular adverse events and risk of hypermagnesemia. The results still need to be confirmed by more high-quality and large-sample RCTs.