Ischaemic postconditioning reduces serum and tubular TNF-α expression in ischaemic-reperfused kidney in healthy rats

OBJECTIVE

We studied the protective effects of postconditioning (PS) in healthy and hypercholesterolemic rats after renal ischaemia-reperfusion (IR) injury. We aimed to examine cytokine expression and apoptosis in tissue damage after revascularisation (TNF-α levels in serum and tissue).

METHODS

Male Wistar rats (n = 32) were divided into four groups. The animals of normal feed groups (NF) were fed with normal rat chow and the cholesterol feed groups (CF) were fed with 1.5% cholesterol containing diet for 8 weeks. Anaesthetized rats underwent a 45-min cross-clamping in both kidney pedicles. Ischaemia was followed by 120-min reperfusion with or without PS protocol (group PS vs. IR). Postconditioning was induced by four intermittent periods of ischaemia-reperfusion of 15-s duration each. Serum cholesterol, triglyceride, urea and creatinine levels were determined. Proinflammation was characterized by the measurement of serum TNF-α. Tissue injury in kidney was determined by formaline-fixed, paraffin-embedded tissue sections. Tissue TNF-α levels were determined by immunohistochemistry.

RESULTS

Significant elevation was observed in serum TNF-α level after IR injury in normal feed groups, which was reduced by PS. In CF group neither the elevation nor the postconditioning induced reduction were as significant as in the NF groups. In normal feed group PS caused a significant reduction in tissue TNF-α level which was significantly higher in CF.

CONCLUSIONS

Ischaemic postconditioning proved to be an effective defense against IR in NF groups, but it was ineffective in CF groups in kidney tissue.

Preconditioning is a method that may reduce the negative side-effect of pneumoperitoneum

Increased intra-abdominal pressure during laparoscopy leads to hypoxia due to reduced blood flow. Aim of our study was to investigate whether preconditioning can reduce this negative effect of the pneumoperitoneum. Fifty female Wistar rats were used, divided into 5 groups. I: Sham operation (Sham), II: conventional pneumoperitoneum (PP), III: transvaginal pneumoperitoneum (TV), IV: preconditioning for 2.5 minutes in two cycles (Pre 2.5), V: preconditioning for 5 minutes (Pre 5). Malondialdehyde (MDA), reduced glutathione (GSH), sulfhydrylgroup (SH-) concentrations, superoxide-dismutase (SOD) and mieloperoxidase (MPO) activity, and anti-apoptotic pathway marker p-AKT level and inflammatory cytokine TNF-α were measured. SOD activity and GSH concentration were decreased in PP and TV groups comparing to Sham and preconditioning groups. MPO activity was decreased also in PP and TV groups comparing to the Sham group but in the preconditioning groups it has remained high. MDA concentration in plasma was increased in PP and TV groups comparing to Sham and preconditioning groups. There was no difference in the case of blood MDA and SH-concentrations between groups. Anti-apoptotic pathway marker p-AKT level was decreased in the TV group comparing to the sham and preconditioning groups. TNF-α level was increased in TV and preconditioning groups compared to the sham group. According to the results preconditioning can reduce negative effects of pneumoperitoneum.

Transgastric small bowel resection by using hybrid technique — Experimental study

Introduction:The Natural Orifice Transluminal Endoscopic Surgery (NOTES) is an abdominal operation carried out with flexible endoscopic instruments and their advanced versions via natural orifices. The NOTES causes theoretically less pain, operative stress, shorter hospitalization, quicker recovery and it is scarless. The aim of this investigation was to evaluate the feasibility and safety of transgastric small bowel resection. Materials and methods: Seven domestic pigs were investigated and entered the study; body weight 25 kg in average. General anesthesia was performed. One trocar was used for laparoscopic observations during gastrotomy and transgastric penetration with the gastroscope, later for assistance with a grasper for manipulation of the bowel loops and for the application of the linear stapling device. Then the needle knife was used to complete a 1.5 cm long incision in the gastric wall. The gastroscope was advanced into the peritoneal cavity and a small bowel loop was identified and elevated with a flexible grasper. Through the second channel of the scope a coag grasper was used to dissect the mesentery. Then a linear stapler was inserted through the assisting trocar and the resection was performed. Afterwards the bowel ends were opened with the needle knife and the stapler was reinserted for a side-to-side anastomosis. The specimen was removed via the stomach. Gastric closure was completed by laparoscopic mini-instruments through the stapler-port. All special events and all problems were prospectively documented. Follow-up was performed over 2 weeks and body weight was recorded. Then a laparoscopy was performed to document adhesions or abscess formation. Finally the animals were sacrificed to evaluate further evidence of infection or adhesions. Results: The operations were carried without complications, there was no case of letal outcome. On the 12th day the abdominal laparoscopic revision was carried out, after the revision in one case adhesion could be detected, no other kinds of complications were noticed. Conclusion: According to our results, the transgastric small bowel resection is a safe procedure, but further special instruments are needed. These experimental procedures should be evaluated carefully and critically in clinical practice.