A new utilization area for hyperbaric oxygen? Improving quality of stored blood.

BACKGROUND/AIM: Since blood bags have the ability for diffusion of gases, we investigated whether hyperbaric oxygen (HBO) exposure affects several vital parameters of stored blood. MATERIALS AND METHODS: Bloods obtained from the same persons were used as both control and HBO groups and stored in pediatric bags with citrate-phosphate-dextrose solution. HBO administration was performed at 2.5 atm for 90 min, started 1 day after blood collection and repeated every 2 days for a total of 10 times. The study was terminated on the 21st day. Complete blood count, glucose, pH, and osmotic fragility values were measured every week. RESULTS: Glucose and pH levels decreased in stored blood. In the HBO-exposed group, these decreases were less than in the control. In addition, mean corpuscular and platelet volumes tended to increase during storing process, but with HBO, these indexes remained lower, near physiologic levels. Another interesting finding of the study was the relative stable osmotic fragility ratio in the HBO group compared to the control blood. CONCLUSION: HBO exposure has positive effects on pH, stability of erythrocytes, and energy source (glucose) of the medium. Thus, we concluded that HBO may be a useful application for life and quality of stored blood.

Effects of hyperbaric oxygen treatment on liver functions, oxidative status and histology in septic rats.

OBJECTIVE: The liver is thought to be responsible for multiple organ failure during sepsis. Increase in tissue oxygen consumption is a major component of the septic response. Hyperbaric oxygen (HBO) therapy provides more oxygenation in the whole body. This study examined the effect of HBO alone or in combination with cefepime (CEF) on the liver in septic rats. DESIGN AND INTERVENTIONS: We divided 90 male rats into six groups; control, HBO, sepsis (SEP), SEP+HBO, SEP+CEF, and SEP+CEF+HBO. Sepsis was induced with an intraperitoneal injection of Escherichia coli (2.1 x 10(9) cfu). A total of six HBO sessions were performed at 2 atm absolute for 90 min at 6-h intervals. CEF was administered intraperitoneally at a dose of 50 mg/kg twice daily. Animals were killed 48 h after sepsis induction. Their liver and blood were removed for biochemical and histopathological analysis. MEASUREMENTS AND RESULTS: Liver thiobarbituric acid reactive substances as well as serum alanine transaminase, aspartate transaminase and alkaline phosphatase levels increased while the activity of the antioxidant enzymes superoxide dismutase and catalase decreased significantly in septic rats. These parameters returned to nearly control levels in the SEP+CEF+HBO group. Histological observations supported these findings: Hepatocellular degeneration was observed and intensive polymorphonuclear cell infiltration appeared in all fields of septic animal livers. HBO alone could not sufficiently reverse these histopathological changes, but most liver sections presented normal histology when it was combined with CEF. CONCLUSIONS: HBO may be a useful adjuvant therapy modality to improve the efficacy of sepsis treatment.

Correlation between hyperbaric oxygen exposure pressures and oxidative parameters in rat lung, brain, and erythrocytes.

OBJECTIVES: The oxygen toxicity risk of hyperbaric oxygen (HBO) treatment has long been of interest. However, there are no comprehensive articles describing the relationship between HBO protocols and oxidative parameters used clinically. The purpose of this study was to determine the effects of various HBO pressure modalities on the oxidative values of rat lung, brain, and erythrocytes. DESIGN AND METHODS: A total of 64 male Sprague-Dawley rats was randomly divided into 7 groups. Group A was used as a control. Groups C to G were subjected to 100% oxygen at a pressure of 1, 1.5, 2, 2.5, and 3 ATA (atmosphere absolute), respectively, for 2 h. Group B was exposed to normal atmospheric air at 3 ATA for the same duration. The rat's lung, brain, and blood were taken immediately after the exposure and thiobarbituric acid reactive substances (TBARS) and superoxide dismutase (SOD) levels were determined. RESULTS: Both TBARS levels and SOD activity increased concordantly with the pressure increase. Although a statistically significant change in TBARS levels started from 100% oxygen exposure at 1 ATA (normobaric), SOD activity was affected after 2 ATA. A significant correlation exists between exposure pressure and the aforementioned parameters. Ambient air exposure at 3 ATA did not affect any parameters besides the brain TBARS levels. CONCLUSIONS: It is clear that HBO exposure causes oxidative stress. The main reason for this effect seems to be exposure to pure oxygen, since pure high pressure has no significant effect on the aforementioned parameters. However, clinicians should use as low pressures as possible since all oxidative parameters appear to be directly proportional to the extent of HBO exposure.

Exogenously administered and endogenously produced melatonin reduce hyperbaric oxygen-induced oxidative stress in rat lung.

Hyperbaric oxygen (HBO) is a widely used treatment modality in many diseases. A known side effect of HBO is the production of reactive oxygen species. Many antioxidants such as vitamins C and E, riboflavin and selenium have been used successfully to scavenge the reactive oxygen species caused by HBO administration. In this study, we aimed to see if melatonin, a newly discovered antioxidant, has a protective effect against the overproduction of reactive oxygen species produced by HBO in rat lung tissue. Sixty male Sprague-Dawley rats were divided into 5 groups as follows: control, daytime HBO (3 ATA, 120 min), daytime HBO plus melatonin (10 mg/kg), nighttime HBO and nighttime HBO (under light exposure). The MDA, SOD and CAT levels of daytime and nighttime HBO (under light exposure) increased significantly. This significance was not found in the daytime HBO plus melatonin and nighttime HBO groups when compared with the control. In this study, HBO caused oxidant stress, and melatonin decreased the levels of MDA, SOD and CAT. Moreover, endogenous melatonin was found to be a more effective antioxidant than exogenous 10 mg/kg melatonin.

Involvement of nitric oxide and hyperbaric oxygen in the pathogenesis of cyclophosphamide induced hemorrhagic cystitis in rats.

PURPOSE: We evaluated the relationship between nitric oxide and hyperbaric oxygenation in the pathogenesis and treatment of cyclophosphamide induced hemorrhagic cystitis in rats. MATERIALS AND METHODS: Cyclophosphamide (100 mg/kg) was injected in male Sprague-Dawley rats for cystitis induction. Animals were treated before and the day after cyclophosphamide injection with 100 mg/kg of the nitric oxide substrate L-arginine, 20 mg/kg of the nonselective nitric oxide synthase inhibitor L-NG-nitroarginine methyl ester and 20 mg/kg of the selective inducible nitric oxide synthase inhibitor S-methylisothiourea. Animals were exposed to hyperbaric oxygen (2.8 atmospheres absolute for 90 minutes twice daily) with or without the administration of L-arginine and nitric oxide synthase inhibitors. RESULTS: Cyclophosphamide injection resulted in severe cystitis. S-methylisothiourea produced marked inhibition of cyclophosphamide induced bladder tissue damage. L-arginine and L-NG-nitroarginine methyl ester failed to a show meaningful protective effect. Hyperbaric oxygen protected the bladder only against ulceration. Moreover, hyperbaric oxygen did not contribute to the protective effects of L-arginine, L-NG-nitroarginine methyl ester or S-methylisothiourea. CONCLUSIONS: Nitric oxide produced by inducible nitric oxide synthase is an important mediator in the pathogenesis of cyclophosphamide induced cystitis. Hyperbaric oxygen has a beneficial effect on repairing bladder damage rather than on bladder protection.