What is minipig vesicoureteral reflux?

  Urinary bladder reflux (VUR) refers to the abnormal physiological phenomenon of bladder urine reflux to the urethra, renal pelvis and limbs caused by a variety of primary or secondary causes. VURs are prone to urea water, nephropathy, secondary infections and stones, impairing renal function, and can cause a series of reflux nephropathy, such as renal scarring, renal atrophy and renal failure. In severe cases, it can develop into end-stage renal disease, namely pediatric dialysis. It is also one of the main reasons for kidney transplantation. The incidence of reflux nephropathy is second only to urine reflux, and some people believe that abnormal development will affect the urinary tract and renal parenchyma, and that kidney damage is caused by postpartum infection. However, animal models could not answer these questions before. There are several models for studying VUR, but they are all new. Many clinical studies have confirmed that the relationship between kidney abnormalities and VUR is reflected in the fetal period. It is necessary to establish a fetal model. The establishment of this model is to establish a series of steps to induce VUR in the uterus by removing the urinary tract.

  1. The experimental design divides 9 pregnant pigs into three groups, and undergoes surgery in the first three months of pregnancy. The surgical procedure is different for each group. (1) In the first group, three pregnant pigs were fasted for 12 hours and were sedated with 0.2 mg/kg xylazine and 1 ml/kg ketamine. Intravenous injection of thiopental sodium was used for anesthesia, smudge and oxygen were given through tracheal intubation to maintain anesthesia, sodium chloride was supplemented intravenously during the operation, and amoxicillin and carbiprofen were infused. Make an incision in the skin on the right side of the back and abdomen, open the abdomen through muscle separation, touch the uterine horns to determine the number of fetuses, put a part of the uterus outside, put it on a wet towel, and cut the uterus along the other end. The fetus passes, avoiding major blood vessels. Cut the amniotic membrane, collect the amniotic fluid, and store it at a temperature consistent with body temperature. The fetal gluteal muscles are then passed through the uterine incision to determine the sex of the fetus. The female fetus immediately returns to the uterus. For each pregnant pig, select three male fetuses to make an incision in the lower abdomen, open the bladder to find the left urinary tract, and then perform excision. Continuously suture the bladder incision with 6-0 polyglycolic acid suture, and suture the incision of the fetal abdominal wall with 5-0 polyglycolic acid suture. Mark each postoperative fetus by cutting off the distal end of the tail, place the fetus back into the uterus, inject amniotic fluid, and suture the amniotic membrane with 4-0 polyglycolic acid suture. The uterus is located in the abdominal cavity. Return and sew the abdominal wall layer by layer with 3-0 polyglycolic acid thread. Pregnant pigs will recover spontaneously and carefully observe the subsequent pregnancy period.

  (2) Group 2 or 4 pregnant pigs. Unlike the first group, Isulin replaced Harlotan. The working environment temperature is about 25°C. Wrap pregnant pigs in heated blankets and illuminate them with heating lamps. The amniotic fluid was not removed, but the amniotic membrane was carefully cut and the posterior quarter of the fetus was placed in the incision to prevent amniotic fluid loss. The fetal heart rate was monitored by ultrasound before and after surgery, and antibiotics were not used directly in the laminar cavity.

  (3) Compared with the first group, the third group has two improvements in operation. One is to inject antibiotics (cephalosporins) directly into the amniotic fluid, and the other is to mark the fetus as a chip implanted under the skin. X-ray pictures of the bladder of twelve newborn pigs after delivery. The control pigs were anesthetized with halothane and oxygen through a face mask, and bladder X-rays were performed. Under ultrasound guidance, the catheter was inserted into the bladder and 10 ml of control solution was injected. After taking pictures, the newborn pigs were sacrificed, and urinary tract anatomy and histological analysis were performed.

  2. As a result, in the first group, 2 pregnant pigs were born naturally, and 1 pig was born through a royal incision. Except for the pigs undergoing intrauterine surgery, they are all muddy, while other newborn pigs are normal. In group 2, the fetal pigs survived during and after ultrasound imaging, but all pregnant pigs stopped production spontaneously one week after the operation, and bacteria were found in the pigs that stopped production. In group 3, a pregnant pig had a distorted uterus during delivery. One of the two fetuses was still born (uterine surgery) and the other was a mummy; the pregnant pig gave birth to healthy newborn pigs ( Only one survived after the operation), development was normal. After delivery, the bladder photos of the 12 newborn pigs in the third group and the X-ray photos of the surviving pigs showed tertiary reflux, the renal pelvis system was significantly dilated, and the renal parenchyma became thinner, but histological examination was performed. It's normal. In the early stages of the model, most of the fetuses were lost, but surgical procedures were established for the surviving pigs to ensure the body temperature and ambient temperature during the operation, shorten the anesthesia time, and so on. Improvement is very important. Thorough prevention and storage of amniotic fluid. After improvement, the model can specifically induce the production of neonatal VUR during fetal development. Neonatal renal parenchymal abnormalities are only related to VUR, so its importance lies in the possibility of any treatment for VUR. However, this model cannot answer all uncertain VURs. Other models need to be established to analyze the postpartum kidney condition in more detail and evaluate the results of various treatments.