The effects of cyclophosphamide and its uroprotective agents, mesna and hyperbaric oxygen, on urinary bladder motility in guinea pigs.

The aim of this research was to observe the effects of cyclophosphamide and its uroprotective agents, mesna and hyperbaric oxygen (HBO), on the motility of urinary bladder muscle in guinea pigs. In the experimental groups, mesna and cyclophosphamide were intraperitoneally injected at a dose of 21.5 mg/kg and 68.1 mg/kg, respectively. For the combination of mesna and cyclophosphamide, one dose of mesna was injected 20 min before cyclophosphamide administration and three additional injections of mesna were repeated every three hours. A total of 8 HBO exposures were performed at 2.8 ATA for 90 min twice daily for another experimental group. In the HBO and cyclophosphamide combined group 5 HBO exposures were given prophylactically before cyclophosphamide. The combination of mesna, HBO and cyclophosphamide was administered by the same procedure. The contractions obtained in response to acetylcholine (ACh, 10(-4) M) in the control group were reduced using cyclophosphamide and HBO individually, but not by mesna. However, the contractions belonging to the various combinations of these three agents were not different from those seen in the control group. On the other hand, the combinations of cyclophosphamide, mesna and HBO showed higher responses to ACh than the groups in which cyclophosphamide and HBO were used individually, while the responses elicited by the cyclophosphamide and HBO combination were greater than those seen in the group treated with HBO only.

Comparison of the uroprotective efficacy of mesna and HBO treatments in cyclophosphamide-induced hemorrhagic cystitis.

The aim of this research was to compare the protective effects of mesna, hyperbaric oxygenation (HBO), and their combination in cyclophosphamide-induced hemorrhagic cystitis in guinea pigs. Following one dose of i.p. 21.5 mg./kg. mesna administration 20 minutes before i.p. 68.1 mg./kg. cyclophosphamide, 3 additional doses of mesna were given every three hours. A total of 8 HBO exposures, 5 of which were applied prophylactically before cyclophosphamide, were performed at 2.8 ATA for 90 minutes 2 times a day. Although mesna or HBO provided significant protection for cyclophosphamide-cystitis in animal bladders, there was also significant damage compared with controls. The combination of mesna and HBO, which act through independent mechanisms, resulted in complete protection, since mean histological scores and hematuria levels in this group were not different from controls (p >0.05). Therefore, this combination may be a useful tool in the prophylaxis and treatment of cyclophosphamide-induced hemorrhagic cystitis.

Protective effect of antioxidant vitamins on red blood cell lipoperoxidation induced by SO2 inhalation.

The aim of this research was to determine whether administration of antioxidant vitamins can reduce oxidant damage in erythrocytes induced by sulfur dioxide (SO2) inhalation. Meth- and sulfhemoglobin ratios, malonyldialdehyde (MDA) levels, osmotic fragility ratios and hematological parameters of a total of 28 rats were compared. SO2 was given at 10 ppm, 1 hour daily, for 45 days in a specially designed chamber. DL-alpha-Tocopherol acetate (40 mg/kg) and Na-ascorbate (200 mg/kg) treatments, initiated 3 days before SO2 exposures, were applied intraperitoneally 3 times a week for 45 days. Meth- and sulfhemoglobin ratios, MDA levels and osmotic fragility ratios were significantly higher in the SO2-treated group (p < 0.05). Significant decreases in MDA levels and osmotic fragility ratios were observed in the antioxidant-treated group (p < 0.05). SO2 inhalation resulted in higher MDA levels and osmotic fragility ratios, which can be reduced by vitamin E + C combination.

The effect of antioxidant vitamins E and C on lipoperoxidation of erythrocyte membranes during hyperbaric oxygenation.

The aim of this research was to determine whether administration of an antioxidant vitamin combination can reduce oxidative damage in erythrocytes induced by hyperbaric oxygenation (HBO). Malonyldialdehyde (MDA) levels and osmotic fragility ratios in erythrocytes of 28 rats were compared in group A [control], group B [Vitamin (E + C)], group C [HBO] and group D [HBO + Vitamin (E + C)]. HBO was applied at a pressure of 2.8 atmospheres absolute (ATA), 1 hour daily, for 45 days in groups C and D. Administration of alpha-tocopherol acetate (40 mg/kg) and Na-ascorbate (200 mg/kg) was initiated 3 days before the start of HBO exposures and administered intraperitoneally 3 times a week for 45 days. MDA levels and osmotic fragility ratios were significantly higher in group C than in groups A and B (p < 0.05 for all). Significant decreases in MDA levels and osmotic fragility were observed in group D compared with group C, although these parameters were still significantly higher than in controls (p < 0.05 for all). Prolonged HBO resulted in oxidative damage indicated by significant increases in MDA levels and osmotic fragility ratios, which were reduced by concomitant vitamin (E + C) administration.

The effects of sulfur dioxide inhalation and antioxidant vitamins on red blood cell lipoperoxidation.

An attempt was made to determine whether sulfur dioxide (SO2,) inhalation at 10 ppm, 1 hr daily, for 30 days induces oxidant stress and whether vitamin E (40 mg/kg) together with vitamin C (200 mg/kg), administered intraperitoneally once in every 3 days, can reduce the damage in red blood cell membranes of guinea pigs. Malonyldialdehyde (MDA) levels, osmotic fragility ratios, and methemoglobin and sulfhemoglobin values were significantly higher in the SO2-treated group compared with the control group (P < 0.05), and marked decreases in MDA levels and osmotic fragility ratios were determined in the group treated with SO2 + antioxidant vitamins (P < 0.05).