Investigation of hyperbaric oxygen therapy efficency in the treatment of renal injury due to unilateral ureteral obstruction: An experimental study in rat model

Aim: The aim of this study was to determine the effect of hiperbaric oxygen (HBO) treatment on renal injury due to acute unilateral ureteral obstruction (UUO) in rats.Materials and Methods: Twenty-eight male Wistar albino rats were randomly divided into four groups. Group I, underwent a control group and only HBO treatment was performed for 10 days. Group II sham operation; Group III left UUO and Group IV left UUO and HBO treatment was performed for 10 days.All surgical procedures were performed while the rats were under a single intramuscular injection of 60 mg/kg ketamine and 9 mg/kg xylazine. An incision was made in the midline of the abdomen, and the left proximal ureter was exposed and was ligated using 3-0 silk.HBO treatment was performed with a monoplace chamber. The rats in groups I and IV were subjected to two session of HBO (2.8-ATA treatment for 60 minutes) per day during 10 days after the surgery.Kidneys from all groups were collected from animals after sacrification. Histological specimens were fixed in 10% formalin solution. After routine paraffin embedding procedure for specimens, sections were stained routinely with hematoxyline-eosine stain for histochemical observation. In addition, e-NOS and i-NOS distributions were also detected using indirect immunohistochemistry technique.Results: After histochemical observation, cortex and medulla of kidney were observed as normal in group 1 and group 2. However, while glomerules were normal in both group 3 and group 4, there were picnotic nuclei and edema in collecting tubule cells. After TUNEL staining, while the TUNEL positive cells were negative in control group, they were detected other groups. TUNEL positive cells were rarely observed in sham group, they were increased in obstructive groups. However, after treatment with HBO, the number of TUNEL positive cells decreased. After immunohistochemical observation, weak immunoreactivities of e-NOS and i-NOS were detected in group 1 in both cortex and medulla, weak immunoreactivity of e-NOS and moderate immunoreactivity of i-NOS were observed in group 2. In group 3, e-NOS and i-NOS immunoreactivites were increased when compared with group 1, 2 and 4, after treatment with HBO, sligtly decreased intensity of e-NOS and i-NOS were detected. Glomerules in all group were not stained positively. Caspase-3 immunoreactivity was negative in both control and sham groups, it was slightly more detectable in obstructive group when compared with treated group.Conclusion: After obstruction of kidney, the apoptosis and the secretion of e-NOS, i-NOS and caspace-3 were slightly inhibited after short time period of HBO treatment.