Objective To investigate the effect of hydrogen peroxide (H_2O_2) on apoptosis and calcium ion concentration of skeletal muscle satellite cells (SMSCs) in rats, and to explore the protective effect of erythropoietin (EPO).Methods The cultured SMSCs were divided into five groups: control group,H_2O_2 group, 10, 20 and 40 U/ml EPO intervention groups.Apoptosis rates and calcium ion concentration of SMSCs were analyzed by flow cytometry, and the morphology of apoptotic cells was observed by Hoechst33258 staining.Results The apoptosis rates showed significant differences (all P<0.05) among (1.93±0.57)% in control group, (22.13±1.79)% in H_2O_2 group, (16.47±2.53)%, (4.97±0.55)% and (2.93±0.47)% in 10, 20 and 40 U/ml EPO intervention groups, respectively.And calcium ion concentrations in SMSCs were 12.67 ±0.32, 27.90±0.06 and 44.53±0.93 in 10, 20 and 40 U/ml EPO intervention groups, respectively.There was significant difference in calcium ion concentration between H_2O_2 group and control group (9.70±0.09 vs.51.37± 0.64, P< 0.05).Morphology of apoptosis was observed by Hoeehst33258 dye stains in 10, 20 U/ml EPO intervention group and H_2O_2 group, while there were less apoptotic bodies in 40 U/ml EPO intervention group and control group.Conclusions EPO might have protective effects on SMSCs injured by H_2O_2 through inhibiting apoptosis and calcium ion releasing from SMSCs.

Ureteral artery fistula (UAF) is a rare complication after long-term indwelling of ureteral stent. In this study, two cases were presented. Both of them underwent pelvic tumor surgery and radiotherapy, and had a history of cutaneous terminal ureterostomy and long-term indwelling of ureteral stents. The first case, a 52-year-old female, was admitted to hospital because of intermittent bleeding from ureteral dermostomy for 1 week on April 2, 2020. CT examination revealed hematocele in the left upper urinary tract, and left nephrectomy was performed.However, bleeding still presented and the distal ureteral resection was performed at the same time, and partial ureteral was ligated. Postoperative diagnostic was ureteral artery fistula. After 8 months of follow-up, no recurrent bleeding presented. Another case, a 82-year-old male, was admitted to hospital because of bleeding at the ureteral dermostomy for an hour on June 15, 2020. Contrast enhanced CT examination revealed intersecting of the left ureter and common iliac artery, and interventional surgery was performed, by which UAF was diagnosed. Embolization of left internal iliac artery and stent implantation of common iliac artery and external iliac artery were performed intraoperatively. The bleeding stopped immediately after the operation, and there was no further bleeding during follow-up of 6 months.