Efficacy of meniscus suture absorbability on meniscus healing success rate via second-look arthroscopy after meniscal repair: a systematic review and meta-analysis.

BACKGROUND: To preserve the meniscus's function, repairing the torn meniscus has become a common understanding. After which, the search for the ideal suture material is continuous. However, it is still controversial about the efficacy of suture absorbability on meniscus healing. METHODS: This review is designed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. INCLUSION CRITERIA: (1) Studies on meniscus repair; (2) Second-look arthroscopy was performed; (3) The meniscus was repaired by absorbable and non-absorbable sutures; (4) The healing condition of repaired meniscus via second-look arthroscopy was described. EXCLUSION CRITERIA: (1) Animal studies, cadaveric studies, or in vitro research; (2) Meniscus transplantation; (3) Open meniscus repair; (4) Reviews, meta-analysis, case reports, letters, and comments; (5) non-English studies. MEDLINE, Embase, and Cochrane Database were searched up to October 2022. Risk of bias and methodology quality of included literature were assessed according to ROBINS-I and the modified Coleman Methodological Scale (MCMS). Descriptive analysis was performed, and meta-analysis was completed by RevMan5.4.1. RESULTS: Four studies were included in the systematic review. Among them, three studies were brought into the meta-analysis, including 1 cohort study and 2 case series studies about 130 patients with meniscal tears combined with anterior cruciate ligament injury. Forty-two cases were repaired by absorbable sutures, and 88 were repaired by non-absorbable sutures. Using the fixed effect model, there was a statistical difference in the healing success rate between the absorbable and the non-absorbable groups [RR1.20, 95%CI (1.03, 1.40)]. CONCLUSION: In early and limited studies, insufficient evidence supports that non-absorbable sutures in meniscus repair surgery could improve meniscal healing success rate under second-look arthroscopy compared with absorbable sutures. In contrast, available data suggest that absorbable sutures have an advantage in meniscal healing. TRIAL REGISTRATION: The review was registered in the PROSPERO System Review International Pre-Registration System (Registration number CRD42021283739).

Tranexamic acid is beneficial for blood management of high tibial osteotomy: a randomized controlled study.

INTRODUCTION: The purpose of this study was to investigate whether TXA can effectively reduce blood loss after HTO and related complications and to evaluate its safety. MATERIALS AND METHODS: From March 2016 to March 2018, 100 patients who underwent medial opening wedge HTO in the Department of Orthopedics, the second affiliated hospital of xi'an jiaotong university, with an average age of 52.8 ± 3.2 years, were randomly divided into the TXA group (using intravenous TXA) and the control group (using the same amount of normal saline), with 50 patients in each group. The postoperative wound drainage volume, decrease in hemoglobin and hematocrit value, total blood loss, wound healing, blood transfusion, deep venous thrombosis (DVT) and pulmonary embolism (PE) were compared between the two groups. RESULTS: The drainage volume on the first postoperative day and the total drainage volume of the TXA group were significantly lower compared with those of the control group (145.7 vs 264.5 ml, 282.3 vs 413.2 ml, P < 0.05). The decreases in the hemoglobin and hematocrit values on the postoperative first, second and fifth days were lower in the TXA group than those in the control group (1.4 VS 3.5, 2.6 vs 3.3, 1.9 vs 2.9 g, P < 0.05; 3.3 vs 5.5, 5.0 vs 9.1, 3.8 vs 7.2%, P < 0.05), and the mean total blood loss was also lower in the TXA group than that in the control group (477.9 vs 834.6 ml, P < 0.05). In the control group, 1 patient had wound hematoma requiring additional paracentesis and pressure dressing, 1 patient had superficial wound infection requiring additional debridement, and 1 patient had postoperative blood transfusion compared to none in the TXA group (P > 0.05). There was no symptomatic DVT or PE in either of the groups. CONCLUSION: Intravenous TXA can effectively and safely reduce blood loss and bleeding-related complications after HTO and was beneficial for the blood management of HTO.

The modified cross-suture technique for unilateral pulled-out anchor during all-inside meniscal repair.

BACKGROUND: Meniscal repair has received increasing attention, but for inexperienced doctors, unilateral suture anchor pulling out may occur during all-inside meniscal repair, and the treatment outcome may be affected. When the errors happened intraoperatively, how to minimize the loss under guaranteeing of treatment effectiveness is a topic worth studying. PURPOSE: To explore the practicability and effectiveness of the modified cross-suture method for arthroscopic remediation of unilateral suture anchor pulling out of an all-inside meniscal repair system. METHODS: From May 2014 to May 2017, 28 patients diagnosed with injuries of the meniscus and anterior cruciate ligaments (ACL) from the First Department of Orthopaedics of the Second Affiliated Hospital of Xi'an Jiaotong University were enrolled in the study as the observation group, including 18 males and 10 females with an average age of 25.5 ± 2.3 years (range 18-42 years). All patients underwent ACL reconstruction concurrently. All meniscus injuries were repaired with an all-inside meniscal repair technique, and 1-3 needles of unilateral suture anchor pulling out occurred intraoperatively. The modified cross-suture method was used to remedy the error of anchor pulling out and to eventually complete an effective repair. Another 30 patients who underwent ACL reconstruction and all-inside meniscal concurrently without unilateral suture anchor pulling out, including 20 males and 10 females with an average age of 26.3 ± 1.9 years (range 19-45 years), were enrolled as the control group. During postoperative follow-up, range of motion, Lachman test and pivot shift test were performed during the physical examination. The clinical healing of the meniscus was evaluated according to the Barrett standard. The meniscus healing status was also confirmed with magnetic resonance imaging (MRI). The function of the knee joint was evaluated according to the IKDC, Lysholm and Tegner scores. RESULTS: Twenty-five patients in the observation group and 28 patients in the control group completed the follow-up, with an average follow-up of 18.4 ± 5.2 months. All operations were performed by the same surgeon. At the follow-up 1 year after the operation, the average knee ROM of the two groups was 125.2 ± 4.3 degrees and 124.7 ± 3.8 degrees, the clinical healing rate of the meniscus of the two groups was 92.0% (23/25) and 92.9% (26/28), the MRI healing rate of the menniscus of the two groups was 72.0% (18/25) and 71.4% (20/28), and the IKDC, Lysholm and Tegner scores of the two groups were 90.52 ± 2.8, 89.17 ± 3.1, and 6.81 ± 1.7 and 91.42 ± 1.9, 90.32 ± 3.4, and 7.02 ± 1.4, respectively. The differences were not statistically significant (P > 0.05). CONCLUSIONS: The modified cross-suture method is practicable and effective for arthroscopic remediation of unilateral suture anchor pulling out in an all-inside meniscal repair system.

A Method of Accurate Bone Tunnel Placement for Anterior Cruciate Ligament Reconstruction Based on 3-Dimensional Printing Technology: A Cadaveric Study.

PURPOSE: To explore a method of bone tunnel placement for anterior cruciate ligament (ACL) reconstruction based on 3-dimensional (3D) printing technology and to assess its accuracy. METHODS: Twenty human cadaveric knees were scanned by thin-layer computed tomography (CT). To obtain data on bones used to establish a knee joint model by computer software, customized bone anchors were installed before CT. The reference point was determined at the femoral and tibial footprint areas of the ACL. The site and direction of the bone tunnels of the femur and tibia were designed and calibrated on the knee joint model according to the reference point. The resin template was designed and printed by 3D printing. Placement of the bone tunnels was accomplished by use of templates, and the cadaveric knees were scanned again to compare the concordance of the internal opening of the bone tunnels and reference points. RESULTS: The twenty 3D printing templates were designed and printed successfully. CT data analysis between the planned and actual drilled tunnel positions showed mean deviations of 0.57 mm (range, 0-1.5 mm; standard deviation, 0.42 mm) at the femur and 0.58 mm (range, 0-1.5 mm; standard deviation, 0.47 mm) at the tibia. CONCLUSIONS: The accuracy of bone tunnel placement for ACL reconstruction in cadaveric adult knees based on 3D printing technology is high. CLINICAL RELEVANCE: This method can improve the accuracy of bone tunnel placement for ACL reconstruction in clinical sports medicine.

Ginsenoside Rd attenuates mitochondrial permeability transition and cytochrome C release in isolated spinal cord mitochondria: involvement of kinase-mediated pathways.

Ginsenoside Rd (Rd), one of the main active ingredients in Panax ginseng, has multifunctional activity via different mechanisms and neuroprotective effects that are exerted probably via its antioxidant or free radical scavenger action. However, the effects of Rd on spinal cord mitochondrial dysfunction and underlying mechanisms are still obscure. In this study, we sought to investigate the in vitro effects of Rd on mitochondrial integrity and redox balance in isolated spinal cord mitochondria. We verified that Ca2+ dissipated the membrane potential, provoked mitochondrial swelling and decreased NAD(P)H matrix content, which were all attenuated by Rd pretreatment in a dose-dependent manner. In contrast, Rd was not able to inhibit Ca2+ induced mitochondrial hydrogen peroxide generation. The results of Western blot showed that Rd significantly increased the expression of p-Akt and p-ERK, but had no effects on phosphorylation of PKC and p38. In addition, Rd treatment significantly attenuated Ca2+ induced cytochrome c release, which was partly reversed by antagonists of Akt and ERK, but not p-38 inhibitor. The effects of bisindolylmaleimide, a PKC inhibitor, on Rd-induced inhibition of cytochrome c release seem to be at the level of its own detrimental activity on mitochondrial function. Furthermore, we also found that pretreatment with Rd in vivo (10 and 50 mg/kg) protected spinal cord mitochondria against Ca2+ induced mitochondrial membrane potential dissipation and cytochrome c release. It is concluded that Rd regulate mitochondrial permeability transition pore formation and cytochrome c release through protein kinases dependent mechanism involving activation of intramitochondrial Akt and ERK pathways.

Arthroscopic Autologous Iliac Bone Grafting With Double-Row Elastic Fixation and Double Antirotating Anchors for Recurrent Anterior Shoulder Dislocation With Massive Glenoid Bone Defect.

The management of recurrent anterior shoulder dislocations with massive glenoid bone defects typically involves arthroscopic intervention. Autologous iliac bone grafting with double-row elastic fixation reportedly yields excellent outcomes. In this article, we introduce a specialized technique for iliac bone grafting that uses double-row elastic fixation and double antirotating anchors. Implementation of this technique prevents the occurrence of iliac graft rotation.

Hoffa's fracture in a five-year-old child diagnosed and treated with the assistance of arthroscopy: A case report.

BACKGROUND: Hoffa's fracture is a coronal-oriented fracture of the femoral condyle. It is rarely observed in pediatric patients that isolated coronal fracture of the medial femoral condyle accompanies an intact lateral femoral condyle. Only a few cases involving Hoffa's fracture of the medial femoral condyle have been reported in patients with undeveloped skeletons. Such a fracture cannot be observed by routine imaging examinations, thus resulting in possible misdiagnosis and further treatment challenges. CASE SUMMARY: A 5-year-old boy with Hoffa's fracture of the medial femoral condyle suffered from right knee pain and severe swelling after being hit by a heavy object. The patient was misdiagnosed and initially treated in a local primary healthcare center. No improvement in his right knee's extension was observed following conservative treatment for 2 wk. The patient was transferred to our hospital, re-diagnosed using arthroscopy, and underwent open reduction and internal fixation. The therapeutic outcome was satisfactory with the screws removed 7 mo after fixation. At the final follow-up of 40 mo, the range of motion in the knee had recovered. There was no varus-valgus instability. CONCLUSION: Hoffa's fracture is rarely seen in children aged 5 years, let alone in the medial condyle, and can easily be misdiagnosed due to limited physical and imaging examinations. Suspected Hoffa's fracture in preschool children should be confirmed based on arthroscopic findings. Open reduction and internal fixation should be performed to protect the articular surface and prevent long-term complications.

[Total arthroscopic internal drainage technique for the treatment of popliteal cyst].

OBJECTIVE: To compare the clinical effects of total arthroscopic internal drainage and arthroscopic combined with posterior small incision in the treatment of popliteal cyst. METHODS: From January 2015 to January 2017, 60 patients with popliteal cyst were treated, including 29 males and 31 females, aged 30 to 65(47.8±2.5) years old, with a course of disease (8.5±4.2) months. Among them, 30 cases received total arthroscopic internal drainage for popliteal fossa cyst(total arthroscopic group), 30 cases received arthroscopic combined with posterior small incision for popliteal fossa cyst(arthroscopic combined with small incision group). The operation time, intraoperative bleeding volume, incision length, Rauschning and Lindgren grade 0 recovery rate and Lysholm score were compared between the two groups. RESULTS: Twenty-nine patients in total arthroscopy group were followed up, and 28 patients in arthroscopy combined with small incision group were followed up for 8 to 20(12.8±2.1) months. Operation time: total arthroscopic group(45.32±5.71) min, arthroscopic combined small incision group (44.56±3.85) min; Rauschning and Lindgren grade 0 recovery: 23 cases in total arthroscopic group, 22 cases in arthroscopic combined small incision group; postoperative Lysholm score: total arthroscopic group 84.5±11.2, arthroscopic combined small incision group 83.2±12.7; there was no significant difference between the two groups(P>0.05). Intraoperative bleeding volume: total arthroscopic group(5.32±1.25) ml, arthroscopic combined small incision group(20.75±8.18) ml; incision length: total arthroscopic group (1.51±0.34) cm, arthroscopic combined small incision group (7.34±0.75) cm; the difference between the two groups was significant(P<0.05). At the last follow-up, the knee joint was examined by magnetic resonance imaging, and no recurrence of cyst was found. CONCLUSIONS: Total arthroscopic internal drainage and arthroscopic combined with posterior small incision technique for popliteal fossa cyst with intra-articular lesions have the same clinical effect, but less trauma and faster recovery.

[Clinical prospective comparative study on short-term effectiveness of arthroscopic treatment of popliteal cyst between cyctectomy and internal drainage combined with cyctectomy].

Objective: To compare the short-term effectiveness between arthroscopic cystectomy and internal drainage combined with cystectomy in popliteal cyst. Methods: Between March 2014 and March 2017, 56 patients with symptomatic popliteal cyst were enrolled in the study, randomized block design was used to divided the patients into trial group (arthroscopic cystectomy combined with internal drainage group, n=28) and control group (arthroscopic internal drainage group, n=28). Excluding those who had incomplete follow-up and received surgery for other diseases postoperatively, 26 patients in the experimental group and 27 patients in the control group were finally enrolled in the study. There was no significant difference in gender, age, side, course of disease, maximum diameter and grade of popliteal cyst, and associated diseases between two groups ( P>0.05). The operation time, duration of popliteal ecchymosis and the middle back of calf tenderness were observed postoperatively. The circumference of calf at 1 day, 1 week, and 2 weeks after operation were measured and the differences were calculated with the measurement before operation. Lower extremity venous thrombosis was observed by color doppler ultrasonography at 1 week after operation. The effectiveness was evaluated by Rauschning and Lindgren grading criteria. And MRI was used to observe whether the popliteal cyst disappeared or decreased and measured its maximum diameter at 1 year after operation. Results: Patients in both groups were followed up 12-14 months, with an average of 12.5 months. The operation time, duration of popliteal ecchymosis, and the middle back of calf tenderness of the trial group were all longer than those in the control group ( P<0.05), the differences of circumference of calf at 1 day, 1 week, and 2 weeks after operation of the trial group were greater than those in the control group ( P<0.05). Color doppler ultrasonography of the lower extremity at 1 week after operation found that the intermuscular venous thrombosis occurred in 2 cases of the trial group, while no lower extremity thrombosis was found in the control group; and the difference between two groups was not significant ( P=0.236). According to the Rauschning and Lindgren grading criteria, there were 16 cases of grade 0, 6 cases of grade 1, and 4 cases of grade 2 in the trial group, and 17 cases of grade 0, 4 cases of grade 1, and 6 cases of grade 2 in the control group at 1 year after operation. There was no significant difference between 2 groups ( Z=-1.872, P=0.078). Nine cases (34.62%) of the trial group and 13 cases (48.15%) of the control group still have residual cysts by MRI, the maximum diameter of which was less than 2 cm. The cysts disappeared in the remaining patients in both groups, and there was no recurrence during the follow-up. There was no significant difference in cyst residual rate between 2 groups ( χ2=2.293, P=0.852). Conclusion: Compared with arthroscopic internal drainage, the short-term effectiveness of the arthroscopic internal drainage combined with cystectomy had no significant improvement, and the operation time was prolonged, the postoperative complications were obviously increased.

Sildenafil improves blood perfusion in steroid-induced avascular necrosis of femoral head in rabbits via a protein kinase G-dependent mechanism.

OBJECTIVE: The aim of the study were to evaluate the effect of sildenafil against avascular necrosis of femoral head (ANFH) in a rabbit model, and to study the role of protein kinase G (PKG) pathway and vascular endothelial growth factor (VEGF) in ANFH. METHODS: Three weeks after inducing ANFH with methylprednisolone injection, 45 female adult New Zealand white rabbits were divided into three groups and treated as follows: group SI received daily intraperitoneal sildenafil with a dose of 10 mg/kg per day; group SD received daily sildenafil identically to group SI plus auricular vein injection DT3 (a specific PKG inhibitor); group NS received only normal saline. The blood perfusion function in the femoral head was measured by perfusion MRI and ink artery infusion. Bilateral femora heads were examined histopathologically for the presence of osteonecrosis; VEGF of tissue was examined by Western blot analysis; cGMP level and PKG activity were also measured. RESULTS: The incidence of ANFH in SI group was significantly lower than that observed in NS and SD groups (p < 0.05). VEGF in SI group was increased compared to NS group. cGMP level and PKG activity were also significantly different between NS and SI group (p < 0.05). However, these effects of sildenafil in SD group were all markedly inhibited by the administration of DT3 compared to SI group. CONCLUSION: Sildenafil appear to increase the perfusion of femoral head by up-regulating VEGF through PKG pathway. The increased perfusion of femoral head could prevent ANFH.

Transcription factor c-jun regulates ß3Gn-T8 expression in gastric cancer cell line SGC-7901.

Aberrant glycosylation, a common feature of malignant alteration, is partly due to changes in the expression of glycosyltransferases, including ß1,3-N-acetyl-glucosaminyltrans-ferase 8 (ß3Gn­T8), which synthesizes poly-N-acetyllactosamine (poly-LacNAc) chains on ß1,6 branched N­glycans. Although the role of ß3Gn­T8 in tumors has been reported, the regulation of ß3Gn­T8 expression, however, is still poorly understood. In the present study, we used three online bioinformatic software tools to identify multiple c­jun binding sites in the promoter of the ß3Gn­T8 gene. Using luciferase reporter assay, chromatin immunoprecipitation (ChIP) analysis, RT­PCR and western blot analysis, we revealed that c­jun could bind to and activate the ß3Gn­T8 promoter, thus upregulating ß3Gn­T8 expression. This was also confirmed by changes in ß3Gn­T8 activity as demonstrated by flow cytometry, immunofluorescence and lectin blot analysis using LEA lectin. Moreover, expression of glycoprotein HG­CD147, the substrate of ß3Gn­T8, was also regulated by c­jun. In addition, c­jun and ß3Gn­T8 were more highly expressed in the gastric cancer tissues when compared to these levels in the adjacent non­tumor gastric tissues, and ß3Gn­T8 expression was positively correlated with c­jun expression. These results suggest that c­jun plays a significant role in regulating the expression of ß3Gn­T8 in the SGC­7901 cell line and may be involved in the development of malignancy via the activity of ß3Gn­T8.

3'-Azidothymidine may potently inhibit the biosynthesis of polylactosamine chains on highly glycosylated-CD147 and reduce matrix metalloproteinase-2 expression in SGC-7901 and U251 cells.

Alterations to N­linked glycans are closely associated with cancer progression. Of particular importance in tumor growth and invasion, is the synthesis of complex N­linked oligosaccharides containing poly­N­acetyllactosamine (polylactosamine) chains, which have previously been reported to inhibit 3'­azidothymidine (AZT). Cluster of differentiation 147 (CD147) is a glycoprotein that carries ß1,6­branched polylactosamine sugars on its N­glycans. The present study aimed to explore the mechanism by which AZT may affect matrix metalloproteinase­2 (MMP2) expression and the cell cycle via regulation of the N­glycans on CD147 in SGC­7901 and U251 cell lines. Subsequent to treatment with various concentrations of AZT, the N­glycans of highly glycosylated (HG)­CD147 were observed to decrease in the two cell lines, and the expression of MMP2 was also significantly decreased. In addition, cell cycle analysis demonstrated that the percentage of the cells in the G1 phase increased in a dose­dependent manner with AZT treatment, indicating that AZT may inhibit cell proliferation in SGC­7901 cells. It was suggested that AZT may reduce the biosynthesis of polylactosamine chains on CD147 and reduce MMP2 expression to inhibit cell proliferation in SGC­7901 and U251 cells. Thus, AZT is suggested to be an antineoplastic drug, which may be effective therapeutically for certain types of cancer through acting on the N­glycans of HG­CD147.

Knockdown of ß3GnT8 reverses 5-fluorouracil resistance in human colorectal cancer cells via inhibition the biosynthesis of polylactosamine-type N-glycans.

Aberrant glycosylation is known to be associated with cancer chemoresistance. ß-1,3-N-acetyl-glucosaminyltransferase (ß3GnT)8, which synthesizes polylactosamine on ß1-6 branched N-glycans, is dramatically upregulated in colorectal cancer (CRC). 5-Fluorouracil (5-FU) resistance remains a major obstacle to the chemotherapy of CRC. However, little is known with regard to the correlation between 5­FU resistance and the expression of ß3GnT8 in CRC. In this study, a 5-FU­resistant cell line (SW620/5-FU) was generated, and 50% inhibition concentration (IC50) of 5-FU was determined by MTT assay. Flow cytometry and lectin blot analysis were performed to detect the alteration of polylactosamine structures. Quantitative RT-­PCR and western blot analysis were used to identify and evaluate candidate genes involved in the synthesis of polylactosamine in SW620/5-FU cells. We found polylactosamine chains were significantly increased in SW620/5-FU cells. Inhibition of the biosynthesis of polylactosamine by 3'-azidothymidine (AZT) was able to reduce 5-FU tolerance. Further studies showed that ß3GnT8 expression was also upregulated in 5-FU­resistant cancer cells, and knockdown of ß3GnT8 by RNA interference reversed 5-FU resistance through, at least partly, by suppressing the formation of polylactosamine. In conclusion, the alteration of ß3GnT8 in CRC cells correlates with tumor sensitivity to the chemotherapeutic drug and has significant implication for the development of new treatment strategies.

Colon cancer cells treated with 5­fluorouracil exhibit changes in polylactosamine­type N­glycans.

5-Fluorouracil (5-FU) is the major chemotherapeutic agent for the treatment of colorectal carcinoma, which were found to have N-glycans containing polylactosamine on the cancer cell surface. Alterations in the expression and structure of polylactosamine glycans are associated with cellular differentiation and oncogenesis. However, little is known with regard to the correlation between the levels of polylactosamine expressed in colon cancer cells and the anticancer effect of 5-FU. In the present study, SW620 cells were treated with the half maximal inhibitory concentration (IC50; determined by MTT-assay) of 5-FU. Hoechst 33258 staining and flow cytometric analysis indicated that 5-FU administration resulted in apoptosis in SW620 cells. An increased percentage of cells in S phase was also observed among the SW620 cells treated with 5-FU. Under the same experimental conditions, a decrease in the 5-FU­induced inhibition of polylactosamine glycans was recorded. However, an increase in the activity of alkaline phosphatase was also observed. Furthermore, pretreatment of the SW620 cells with 5-FU inhibited the expression of ß1,3-N-acetylglucosaminyltransferase-8 (ß3Gn-T8) and cluster of differentiation (CD)147 in a time-dependent manner. Overall, changes in glycosylation were associated with the anticancer effect of 5-FU in the colon cancer cells. In conclusion, polylactosamine may be a useful target for the identification of substances with anticancer activity.

Protective effects of necrostatin-1 on glucocorticoid-induced osteoporosis in rats.

The inhibition of bone formation has been suggested to play a central role in the pathogenesis of glucocorticoid-induced osteoporosis (GIOP). Recently, many studies suggested that there may be another mechanism involved in GIOP besides apoptosis. The aim of this study was to investigate the protective effect of Necrostatin-1 on GIOP rats. Forty male Sprague-Dawley rats were randomly divided into four groups (n=10): controls; GIOP rats; GIOP rats pretreated with alendronate; and GIOP rats pretreated with Necrostatin-1. Their bone mineral density (BMD) and body weight were measured at the beginning and at the end of the experiment. TUNEL assay, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to observe the change of cellular morphology induced by Nec-1. The biochemical analysis and histomorphometric analysis were used to evaluate the change of bone formation by Nec-1. RIP-1, RIP-3 and caspase-8 expression were evaluated by immunohistochemistry. We found more TUNEL positive osteocytes and larger lacunae volume in GIOP rats compared with the control group. However, most of the osteocytes displayed a necrotic morphology and mitochondria lesions under TEM. In contrast to alendronate, Necrostatin-1 significantly elevated the level of bone formation markers, while it had no effect on bone resorption markers. Necrostatin-1 also markedly ameliorated trabecular bone. In addition, Necrostatin-1 significantly weaken the immunoreactivity of RIP-1 in GIOP rats while had no effect on RIP-3 and caspase-8. These data suggest, for the first time, that Necrostatin-1 accelerate bone formation of glucocorticoid-induced osteoporosis in rats.

ß3GnT8 regulates the metastatic potential of colorectal carcinoma cells by altering the glycosylation of CD147.

Aberrant glycosylation of cell surface glycoproteins is commonly associated with the invasion and metastasis of colorectal carcinomas, which can be attributed to the upregulated expression of glycosyltransferases. Therefore, elucidation of glycosyltransferases and their substrates may improve our understanding of their roles in tumor metastasis. ß-1,3-N-acetylglucosaminyltransferase-8 (ß3GnT8) is a key enzyme that catalyzes the formation of poly-N-acetyllactosamine (polylactosamine) chains on ß1,6-branched N-glycans in vitro, which is also involved in tumor invasion. In the present study, we analyzed the expression of ß3GnT8 and its product polylactosamine in four human colorectal carcinoma cell lines (LS-174T, SW620, SW480 and LoVo) with different metastatic potential. We found that the levels of ß3GnT8 and polylactosamine chains were gradually increased in the colorectal cancer cell lines in a trend from low to high metastatic potential. Notably, a significantly positive relationship between ß3GnT8 expression and HG-CD147 was noted in the colorectal cancer cell lines. To further investigate their relationships, exogenous ß3GnT8 was introduced into the LS-174T cells, while expression of ß3GnT8 was downregulated in the LoVo cells. The overexpression of ß3GnT8 in LS-174T cells increased the level of HG-CD147. Conversely, downregulation of ß3GnT8 expression in LoVo cells significantly decreased the expression of HG-CD147. HG-CD147 is a major carrier of ß1,6-branched polylactosamine sugars; therefore, the regulation of ß3GnT8 significantly altered the ß1,6-branched polylactosamine structures on CD147. Hence, we suggest that ß3GnT8 plays a key role in the metastasis of colorectal cancer cells by altering the ß1,6-branched polylactosamine sugars of CD147.

ß3GnT8 plays an important role in CD147 signal transduction as an upstream modulator of MMP production in tumor cells.

Aberrant carbohydration by related glycosyl-transferases plays an important role in the progression of cancer. This study focused on the ablity of ß-1,3-N-acetyl-glucosaminyltransferase-8 (ß3GnT8) to regulate MMP-2 expression through regulation of the CD147 signal transduction pathway in cancer cells. ß3GnT8 catalyzes and then extends a polylactosamine chain specifically on ß1-6-branched tetraantennary N-glycans. CD147 is a major carrier of ß1-6-branched polylactosamine sugars on tumor cells, and the high glycoform of CD147 (HG-CD147) induces matrix metalloproteinase (MMP) production. In the present study, we analyzed ß3GnT8 mRNA expression in 6 cancer cell lines (MCF-7, M231, LN229, U87, SGC-7901 and U251). We found that ß3GnT8 expression in the LN229, SGC-7901 and U251 cell lines was higher than that in the other cell lines. Therefore, we established ß3GnT8-knockdown cell lines derived from the LN229 and SGC-7901 cell lines to examine the level of polylactosamine and CD147 N-glycosylation. In addition, tunicamycin is widely used as an inhibitor of N-linked glycosylation. Hence, various concentrations of tunicamycin were used to treat the cells in order to study its influence on CD147 N-glycosylation and MMP-2 expression. In conclusion, we found that ß3GnT8 regulated the level of N-glycans on CD147 and that N-glycosylation of CD147 has an important effect on MMP-2 expression. Our findings suggest that ß3GnT8 affects the signal transduction pathway of MMP-2 by altering the N-glycan structure of CD147.

Inhibition by imatinib of expression of O-glycan-related glycosyltransferases and tumor-associated carbohydrate antigens in the K562 human leukemia cell line.

OBJECTIVE: To study changes of tumor associated carbohydrate antigen (TACAs) expression and mRNA levels for tumor associated glycosyltransferases, and assess subcellular localizations of N-acetyl galactosyltransferases (GalNAc-Ts) in the K562 leukemia cell line after imatinib treatment. METHODS: RT-PCR was performed to analyze the expression of glycosyltransferases which synthesize O-glycan in tumor-associated carbohydrate antigens (TCTAs). The expression of Tn antigen, T antigen and sialyl T antigen on K562 cell membranes was measured by flow cytometry after treatment with different concentrations of imatinib. Co-localization of GalNAc-Ts and ER (endoplasmic reticulum) was determined by confocal laser scanning microcopy. RESULTS: Transcript expression levels of several glycosyltransferases related to TCTAs were decreased after imatinib (0-0.3µM) treatment. Expression of Tn antigen and T antigen was increased while that of sialyl T antigen was decreased. Co-localization of GalNAc-Ts and ER was reduced by 0.2µM of imatinib. CONCLUSION: Imatinib inhibited the expression of O-glycan related TACAs and several related glycosyltransferases, while decreasing the co-localization of GalNAc-Ts and ER and normalizing O-glycosylation in the K562 human leukemia cell.

[Impact of adipose-derived stem cells combined with vascular bundle implantation on vascularized tissue engineering scaffolds in vivo].

OBJECTIVE: To discuss the impact of adipose-derived stem cells (ADSCs) combined with vascular bundle implantation on vascularized tissue engineering scaffolds in vivo so as to provide a theoretical basis for the repair of avascular necrosis of the femoral head. METHODS: ADSCs were isolated from 4-month-old Sprague Dawley (SD) rats and cultured, then were induced to osteogenesis and identified. ADSCs at the 3rd passage were seeded on the nano-hydroxyapatite/polyamide-66 (nHA/PA66) to prepare the composite scaffolds. The compound condition of cells and scaffold materials were observed under scanning electronic microscope (SEM). Twenty-four 4-month-old SD rats (weighing 350-400 g) were randomly divided into 3 groups (n=8). In group A and group B, the inferior epigastric artery and vein of rats were implanted into composite scaffold cultured for 10 days or simple nHA/PA66 scaffold, respectively. In group C, two composite scaffolds cultured for 10 days were embedded into quadriceps femoris muscle of both thighs, respectively. After 2 and 4 weeks of operation, angiogenesis was observed by HE staining and CD34 immunohistochemical staining. RESULTS: Cells isolated from adipose were identified as ADSCs. SEM showed that the number of cells increased after being cultured for 10 days, cell morphology stretched fully with a shape of long spindle. HE staining and immunohistochemical staining showed that a large number of angiogenesis was observed around the implanted artery and vein in group A, which was superior to groups B and C in the number of blood vessels and the maturity of blood vessel wall. After 2 and 4 weeks of operation, the blood vessel density and blood vessel diameter were significantly higher in group A than in group B and group C, and in group B than in group C (P < 0.05). CONCLUSION: Combined application of ADSCs and vascular bundle implantation can promote the degree of vascularization, which could make the scaffold vascularization reliable.