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Influence of hyperbaric oxygenation on gene expression in diabetic and healthy female Sprague- Dawley rats

INTRODUCTION: Our previous study demonstrated increased expression of mRNA CYP4A1 in aortas of healthy male Sprague-Dawley (SD) rats treated with hyperbaric oxygenation (HBO2)1, 2. The aim of this study was to determine the influence of HBO2 on expression of CYP4A1, CYP4A3 and thromboxane-2 synthase (TXA2) (producing vasoconstrictor 20-HETE and TXA2, respectively) and CYP2J3 and CYP4A3 genes (producing vasodilator EETs) in aorta of healthy and diabetic female SD rats. METHODS: Female SD rats - control group, diabetic (DM) group ; and control-HBO2 rats and DM-HBO2 rats that underwent HBO2 (120 minutes in duration, at 2.0 atm for 4 consecutive days, 5th day sacrified) (12 weeks-old at the time of experiment, 6 weeks DM duration) were included in the study (N=9/per group). Diabetes mellitus was induced by 1 injection of 60mg/kg i.p. streptozocin in 6 weeks old rats. Prior to decapitation, rats were anesthetized with ketamin-klorid (75 mg/kg) and midazolam (2.5 mg/kg). Aortas were collected for mRNA expression analysis by RT-PCR. Data are normalized with expression of HPRT housekeeping gene. The data are presented as mean±SEM and analyzed with t-test ; p<0.05 was considered statistically significant. The Ethical Committee of Faculty of Medicine University of Osijek approved the study. RESULTS: There is significant up-regulation of CYP2J3 gene in DM-HBO2 rats compared to all groups, and significantly higher expression of CYP2J3 in control-HBO2 compared to control group. Control group has significantly higher expression of CYP2J3 and CYP4A3 genes compared to DM group. Additionally, expression of CYP4A3 is significantly higher in control-HBO2 compared to DM-HBO2 rats. Control-HBO2 rats had significantly higher expression of TXA2 mRNA compared to DM- HBO2. CONCLUSION: Present results demonstrated that there is a down-regulation of CYP genes in diabetic rats aortas. HBO2 led to up- regulation of CYP genes in both, control and diabetic rats, and in TXA2 expression in healthy- HBO2 rats. This finding is important in light of the role of eicosanoids produced by these enzymes in mediating various vascular responses to vasodilator stimuli, which are changed in diabetes3. Reference: 1. Kibel A, Cavka A, Cosic A, Falck JR, Drenjancevic I. Effects of hyperbaric oxygen treatment on vascular reactivity - responses of rat aortic rings to angiotensin II and angiotensin-(1-7).Undersea Hyperb Med. 2012 ; 39:1053-66. 2. Novak S, Ćosić A, Mihaljević Z, Kibel A, Drenjančević I. Influence of hyperbaric oxygen treatment on vascular gene expression in healthy Sprague-Dawley rat.1st International Doctoral Workshop on Natural Sciences of the University of Pécs (1st IDWoNS / UP), Book of Abstracts.Pecs, Hungary, 30-31.9.2012. 3. Manojlovic D, Cavka A, Drenjancevic I. Vascular relaxation to acetylcholine in female diabetic rats that underwent hyperbaric oxygenation ; the role of EETs and 20-HETE. Proceedings of The Physiological Society 27. London, UK, 2012. PC180

Hyperbaric oxygenation; diabetes mellitus; CYP2J3; CYP4A1; CYP4A3; TXA2 gene expression

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