Objective To generate mice with whole-body overexpression of human METRNL gene.Methods Based on Cre-loxP system,Dppa3-Cre mice were mated with Rosa26-LSL-METRNL knock-in mice(R26-LSL-METRNL+/-)to generate R26-L-METRNL+/-mice.The genotypes of the offsprings were identified,and tissues of the blood,heart,liver,spleen,lung,kidney,brain,white adipose and muscle were collected.The expression of human METRNL gene in mice was investigated by quantitative real-time PCR,western blot and enzyme linked immunosorbent assay.Results Compared with wild type control mice,human METRNL in R26-L-METRNL+/-mice significantly expressed at both mRNA and protein levels in tissues,with abundant METRNL protein in blood.Conclusion The mouse model overexpressing human METRNL gene(R26-L-METRNL+/-mouse)was successfully constructed.

Objective To study the effect of nicotinamide mononucleotide (NMN) on the mortality of the lipopoly-saccharide (LPS)-induced endotoxic shock mouse model. Methods 10-week-old C57BL/6J male mice were randomly divided into groups, and were injected intraperitoneally (i.p.) with LPS (10 mg/kg) to induce endotoxic shock models. NMN was i.p. injected in three ways: (1) 0.5 h after modeling, doses of 10, 30, 100 and 300 mg/kg; (2) 0.5 h before modeling, doses of 30, 100, 300 and 600 mg/kg; or (3) 0.5 and 12 h after modeling, dose of 300 mg/kg each time. The death times of each group were recorded, and the survival curves were drawn. Results Compared with the solvent control group, NMN at different doses given 0.5 h after or before modeling didn’t improve the survival rate or delay the death time of endotoxic shock mice; But when given at 0.5 and 12 h 300 mg/kg after modeling, NMN accelerated the death of mice and increased the mortality of mice. NMN products by two manufacturers showed similar effects. Conclusion NMN has no therapeutic effect on LPS-induced endotoxic shock, and repeated administration of NMN after endotoxic shock will increase the mortality.

Objective:To evaluate the clinical efficacy of the axillary approach in the treatment of scapular glenoid fracture.Methods:A retrospective analysis was performed of the 12 patients who had been treated for scapular glenoid fracture from November 2019 to April 2021 at Department of Upper Limb Orthopaedics, Zhengzhou Orthopaedic Hospital. They were 4 males and 8 females, aged from 30 to 75 years (mean, 53.5 years). According to the Ideberg classification, there were 2 cases of type Ⅰa, 9 cases of type Ⅱ and one case of type Ⅴa. All cases were treated through the axillary approach. Two patients complicated with anterior shoulder dislocation were treated with manual reduction under anesthesia before operation and the other 10 cases with special plate fixation through the axillary approach. The 3 patients complicated with fracture of greater tuberosity were fixated with a special plate through the lateral shoulder split deltoid approach. Constant-Murley score, visual analogue scale (VAS) and Hawkins grading were used at the last follow-up to evaluate shoulder function, pain and stability after operation.Results:All patients were followed up for 9 to 20 months (mean, 14.4 months). The operation time ranged from 55 to 110 min (mean, 76.3 min), intraoperative bleeding from 60 to 160 mL (mean, 103.8 mL), and hospital stay from 8 to 14 d (mean, 11.1 d). All incisions healed primarily and all scapular glenoid fractures got united 6 months after operation. The last follow-up showed no shoulder instability, neurovascular injury or internal fixation failure. At the last follow-up, the range of motion of the shoulder was 159.2°±26.1° in forward bending, 156.7°±29.6° in abduction, 48.3°± 15.3° in external rotation (neutral position), and 73.3°±12.3° in internal rotation (neutral position), and the Constant-Murley score was (94.0±5.3) points. The range of motion of the shoulder and Constant-Murley score were significantly improved compared with those before operation (10.8°±11.6°, 7.5°±11.4°, 5.8°±10.0°, 42.5°±16.0° and 4.9±4.0, respectively) (all P<0.05). The VAS score was 0 in 11 patients and 2 in one patient at the last follow-up. Conclusion:The axillary approach is feasible for the treatment of scapular glenoid fracture, because it is hidden and less invasive, leading to good clinical outcomes.

Objective:To investigate the efficacy of fixation with cannulated screws alone via the Kocher approach in the treatment of adult humeral capitulum fractures.Methods:From August 2016 to August 2020, 16 patients with humeral capitulum fracture were treated at Department of Upper Limb Orthopedics, Zhengzhou Orthopaedic Hospital. They were 10 males and 6 females, aged from 36 to 62 years (average, 45 years). The left side was affected in 10 cases and the right side in 6. According to the Ring classification, 3 cases were type Ⅰ, 3 cases type Ⅱ, 6 cases type Ⅲ, and 4 cases type Ⅳ. All patients were treated with the Kocher approach on the lateral side of the elbow. After reduction under direct vision, the fractures were fixated temporarily with Kirschner wires and finally with cannulated screws. On the second postoperative day, the patients started active flexion and extension of the elbow joint and took indomethacin orally to prevent heterotopic ossification. At the last follow-up, the curative efficacy was evaluated according to the Mayo elbow performance score (MEPS). The flexion and extension of the elbow joint and the rotation of the forearm were also recorded.Results:All patients were followed up for 10 to 19 months (mean, 14.3 months) after surgery. Bony union was achieved after 7 to 12 monthes (average, 11.3 monthes) in all the 16 patients, 2 of whom developed heterotopic ossification. By the MEPS evaluation at the last follow-up, 8 cases were excellent, 6 good and 2 fair, scoring an average of 89.5 points (from 73 to 95 points). At the last follow-up, the elbow flexion ranged from 80° to 130° (averaging 113°), extension from 5° to 30° (averaging 15°), forearm pronation from 62° to 75° (averaging 67°), and forearm supination from 50° to 90° (averaging 75°).Conclusion:When the fracture ends are exposed through the lateral Kocher approach, the fracture fragments fixated with cannulated screws only, and the patients encouraged to start elbow joint exercises in the early stage, the treatment of adult humeral capitulum fractures can result in satisfactory curative effects.

Objective:To compare proximal humerus internal locking system (PHILOS) and Multiloc intramedullary nail in the treatment of proximal humerus fracture-anterior dislocation.Methods:A retrospective study was performed to analyze the data of 33 patients with proximal humerus fracture-anterior dislocation who had been treated by open reduction and internal fixation from June 2015 to April 2021 at Department of Upper Limbs, Zhengzhou Orthopaedic Hospital. According to methods of internal fixation, the patients were divided into an extramedullary group and an intramedullary group. In the extramedullary group of 18 cases subjected to internal fixation with PHILOS, there were 8 males and 10 females with an age of (53.3 ± 10.6) years, and 1 2-part fracture, 15 3-part fractures and 2 4-part fractures by the Neer classification. In the intramedullary group of 15 cases subjected to internal fixation with Multiloc intramedullary nail, there were 8 males and 7 females with an age of (51.5 ± 11.2) years, and 14 3-part fractures and 1 4-part fracture by the Neer classification. The 2 groups were compared in terms of incision length, operation time, intraoperative blood loss, postoperative complications, and visual analog scale (VAS), range of shoulder motion, and Constant-Murley score at postoperative 12 months.Results:The 2 groups were comparable due to insignificant differences in their preoperative general data ( P>0.05). All patients were followed up for (20.8 ± 4.7) months. The incision length in the intramedullary group [(11.6 ± 1.7) cm] was significantly shorter than that in the extramedullary group [(17.6 ± 2.0) cm], and the intraoperative blood loss in the former [(106.7 ± 34.4) mL] was significantly lower than that in the latter [(151.7 ± 45.7) mL] ( P<0.05). The VAS scores at 1 week and 1 month after surgery [2.0 (2.0, 3.0) and 0.0 (0.0, 1.0) respectively] in the intramedullary group were significantly lower than those in the extramedullary group [3.0 (3.0, 3.3) and 1.0 (0.0, 1.3) respectively] ( P<0.05). The external rotation of the shoulder at the last follow-up in the intramedullary group (65.3° ± 15.5°) was significantly larger than that in the extramedullary group (50.6° ± 13.9°) ( P<0.05). There were no significant differences in operation time, incidence of postoperative complications, VAS score at 12 months after operation, Constant-Murley score or range of shoulder motion at the last follow-up between the 2 groups ( P>0.05). Conclusions:In the treatment of proximal humerus fracture-anterior dislocation, open reduction and internal fixation with both PHILOS and Multiloc intramedullary nail can result in a favorable prognosis when the fracture-dislocation is well reduced and fixated. However, the Multiloc intramedullary nail may lead to better early pain relief, less surgical invasion, and better functional recovery of the external rotation of the shoulder.

Objective To study the effects of atherosclerotic high-fat diet on body weight, blood glucose, blood lipid levels and atherosclerotic plaque formation in mice, and to determine the effect of fasting time on the results of blood lipid testing. Methods 10-week-old male ApoE knockout (ApoE^-/-) mice were given high-fat diet and normal diet. The atherosclerotic plaques were observed four months later. 10 week old C57BL/6J male mice were given regular diet for 4 weeks, regular diet for 2 weeks + high-fat diet for two or four weeks. Body weight、liver、glucose, and the serum lipid levels were examined. The influence of fasting for 12 h, 6 h or no fasting on blood lipid detection results before sacrificing were studied. Results The atherosclerotic plaque area of ApoE^-/- mice given high-fat diet increased significantly (P<0.01). C57BL/6J mice given high-fat diet gained weight (P<0.01). The glucose, TC, LDL-c and HDL-c were also increased in C57BL/6J mice with liver fat accumulation while the level of TG was significantly decreased(P<0.01). Compared with the fasting 12 h group, serum triglyceride (TG) was significantly increased (P<0.01）in fasting 6 h and no fasting groups. Conclusion The atherosclerotic high-fat diet can accelerate the formation of atherosclerotic plaques in ApoE^-/- mice, significantly increase blood sugar, TC and LDL-c levels, but significantly reduce TG values.. The fasting time can affect serum triglyceride (TG) level.

Objective To establish and optimize a mouse myocardial infarction (MI) model, and to use twice limb lead ECGs immediately after coronary ligation and 4 h after surgery to evaluate the occurrence of myocardial infarction. Methods Twenty-nine male C57BL/6J mice were anesthetized with isoflurane. then a myocardial infarction model was established by ligating the left anterior descending (LAD) coronary artery through the third/fourth intercostal space of left anterior chest. Immediate and 4 h postoperative limb lead ECGs were performed. Twenty-four hours after surgery, the chest was opened and the occurrence of myocardial infarction was evaluated. The heart samples were taken for TTC staining to determine the infarct area and calculate the infarct area. Results During the mice underwent coronary artery ligation the intraoperative mortality was 6.8% (2/29), and the early postoperative (<4 h) mortality was 10.3% (3/29). The 24 h survival rate was 82.8% (24/29). 24 hours after TTC staining confirmed the occurrence of infarction, the myocardial infarction model was established. The success rate of the model was 79.3% (23/29), and the average infarct size (infarcted myocardial weight / whole ventricular weight) was (28 ± 6)%; The mice successfully established by the model showed obvious ST-T changes in the ECG at 4 hours after surgery, suggesting that a myocardial infarction has occurred. Conclusions The mouse myocardial infarction model was successfully established. The combined use of ECG immediately after surgery and 4 h after surgery could be used as a rapid and non-invasive evaluation method for mouse myocardial infarction.

METRNL is a recently identified secreted protein with emerging functions. This study is to find major cellular source of circulating METRNL and to determine METRNL novel function. Here, we show METRNL is abundant in human and mouse vascular endothelium and released by endothelial cells using endoplasmic reticulum-Golgi apparatus pathway. By creating endothelial cell-specific Metrnl knockout mice, combined with bone marrow transplantation to produce bone marrow-specific deletion of Metrnl, we demonstrate that most of circulating METRNL (approximately 75%) originates from the endothelial cells. Both endothelial and circulating METRNL decrease in atherosclerosis mice and patients. By generating endothelial cell-specific Metrnl knockout in apolipoprotein E-deficient mice, combined with bone marrow-specific deletion of Metrnl in apolipoprotein E-deficient mice, we further demonstrate that endothelial METRNL deficiency accelerates atherosclerosis. Mechanically, endothelial METRNL deficiency causes vascular endothelial dysfunction including vasodilation impairment via reducing eNOS phosphorylation at Ser1177 and inflammation activation via enhancing NFκB pathway, which promotes the susceptibility of atherosclerosis. Exogenous METRNL rescues METRNL deficiency induced endothelial dysfunction. These findings reveal that METRNL is a new endothelial substance not only determining the circulating METRNL level but also regulating endothelial function for vascular health and disease. METRNL is a therapeutic target against endothelial dysfunction and atherosclerosis.