Objective:To analyze the clinical characteristics of bone tumors in children, so as to improve the understanding and diagnosis of bone tumors in children.Methods:The clinical data of bone tumors in children hospitalized in the Affiliated Hospital of Zunyi Medical University from January 2009 to December 2018 were collected, with the age ≤ 14 years old.All children′s gender, age, tumor type, location, number of lesions and first symptoms were counted, and the clinical characteristics of bone tumors in children in this area were analyzed.Results:Totally 548 children with bone tumor were collected, with 344 males and 204 females, and the ratio of males to females was 1.69∶1.00, with 462 single cases and 86 multiple cases.Among the multiple cases (86 cases), 82 cases (95.35%) were benign bone tumors.The total number of cases increased with age.The age of different tumors has its own characteristics.Tibia was the most common tumor location (223 in total), followed by femur (177 in total) and humerus (82 in total). According to the classification of tumor nature, there were 478 cases (87.22%) of benign bone tumors, 43 cases (7.85%) of intermediate bone tumors and 27 cases (4.93%) of malignant bone tumors.The incidence of benign bone tumors was significantly higher than that of intermediate and malignant bone tumors, with statistically significant differences ( χ2=72.604, P<0.05). Among the benign bone tumors (478 cases), osteochondroma was the most common (265 cases), accounting for 55.44%; among the intermediate bone tumors (43 cases), aneurysmal bone cyst was the most common (20 cases), occupying 46.51%; among the malignant bone tumors(27 cases), osteosarcoma was the most common (16 cases), accounting for 59.26%.Among the initial symptoms, 268 cases were local masses, and 166 cases were pain, which were significantly higher than that of 79 without symptoms, with 28 lameness, 4 deformity and 3 dysfunction, and the differences were statistically significant( χ2=71.422, P<0.05). Conclusions:The majority of bone tumors patients in children were male, and the incidence increased with age.Benign and solitary are common, and the multiple cases were mainly benign.The most common locations are tibia and femur.The initial symptoms were mainly local mass and pain.Most importantly, the clinical characteristics of different tumors are slightly different.

Objective:To explore the relationship between the transforming growth factor-β (TGF-β) signaling pathway and steroid-induced osteonecrosis of the femoral head in young rabbits.Methods:Sixty 8-week-old rabbits weighing 1.5-2.0 kg were randomly divided into steroid injection group (48 cases) and control group (12 cases). Rabbits in the former group were injected with Prednisolone Acetate 7.5 mg/kg into bilateral gluteal muscles twice a week for 8 weeks, and those with successful modeling were included in the disease group; otherwise, they were included in the non-disease group.Rabbits in control group were similarly injected with the same volume of 9 g/L saline.Penicillin sodium 50 000 U/rabbit was injected once a week for preventing infection.After 8 weeks of injection, CT was performed in all the experimental animals.They were then sacrificed for collecting bilateral femoral heads.Expression levels of TGF-β1, TGF-β2, Smad2 and Smad3 in the femoral head were detected by enzyme linked immunosorbent assay (ELISA), and the mRNA level of Runx2 in the femoral head was detected by quantitative real-time PCR (qPCR), the expression differences of related factors in each group were compared.Results:In steroid injection group (48 cases), 6 rabbits were sacrificed, and 32 survived, involving 6/32 cases (18.75%) experimental animals with positive avascular necrosis (disease group), and 26 negative ones (non-disease group). ELISA data showed that expression levels of TGF-β1 in control group, non-disease group and disease group were (77.12±14.62) ng/L, (90.17±11.90) ng/L and (126.14±25.66) ng/L, respectively ( t=3.35, 4.24, all P<0.05). The expression levels of TGF-β2 in control group, non-disease group and disease group were (74.54±7.63) ng/L, (89.24±9.51) ng/L and (109.74±16.45) ng/L, respectively ( t=4.12, 5.65, all P<0.01). The expression levels of Smad2 in control group, non-disease group and disease group were (17.74±2.72) μg/L, (23.82±3.58) μg/L and (31.28±3.88) μg/L, respectively ( t= 4.54, 7.99, all P<0.01). The expression levels of Smad3 in control group, non-disease group and disease group were (1.76±0.52) μg/L, (2.39±0.45) μg/L and (3.53±0.47) μg/L, respectively ( t=5.60, 6.71, all P<0.01). qPCR data showed that the mRNA levels of Runx2 in control group, non-disease group and disease group were 1.02±0.17, 1.27±0.14, and 1.72±0.11, respectively ( t=7.60, 8.91, all P<0.01). Conclusions:TGF-β is up-regulated in the model of steroid-induced osteonecrosis of the femoral head in young rabbits, which stimulates the proliferation and differentiation of osteoblasts and osteoclasts, and triggers the process of bone remodeling.The TGF-β signaling pathway involved in the repair of necrotic bone.