Objectives: To determine optimal duration of transient middle cerebral artery occlusion (t- MCAO) for stroke model in female diabetic Sprague-Dawley (SD) rats. To evaluate effects of acute and repetitive hyperbaric oxygenation (HBO2) as well as 20- HETE inhibition by N-hydroxy-N'-(4-butyl-2methylphenyl)-formamidine (HET0016) on experimental stroke outcomes. Material and Methods: 25 streptozotocin-induced type-1 diabetic SD female rats (N=25, 12 weeks old, 5 groups; N=5 per group), were subjected to different duration of t-MCAO (20 minutes (’), 30’, 45’, 60’ and 90’) followed by reperfusion. Control group of rats without diabetes (N=5) was subjected to 30’ of t-MCAO followed by reperfusion. 42 streptozotocin- induced type-1 diabetic Sprague-Dawley female rats (N=42, 12 weeks old, N=7/group), were subjected to transient middle cerebral artery occlusion (t-MCAO) for 30’ followed by reperfusion and divided in following groups; a) control group, without treatment; and groups exposed to; b) HBO2; c) multiple HBO2 (first HBO2 immediately and second 12h after t- MCAO); d) HET0016 pretreatment (1mg/kg/3 days prior to t-MCAO) combined with HBO2 after t-MCAO; e) HET0016 treatment (1h before, during and for 6 hours after t-MCAO); and f) HET0016 treatment followed by HBO2 after t-MCAO. 24h after reperfusion infarct volumes were evaluated by 2,3,5-triphenyltetrazolium chloride (TTC) staining. mRNA expression of CYP2J3, CYP3C11 was determined by real-time qPCR. Results: Intra-ischemic reductions of regional cerebral blood flow (rCBF) were similar in all groups (68%-75% of baseline values). Reperfusion was significantly impaired in 90’ ischemia group (56-62% vs. 80-125% in other groups). 20’ t-MCAO induced small infarct (3±5% of ischemic hemisphere). 30’ ischemia produced significantly larger infarct (46±6%). In 45’ and 60’ ischemia infarct was 52±5% and 59±3% of ischemic hemisphere, respectively. Ischemia of 90’ led to massive stroke (89±6% of ischemic hemisphere encompassing the whole striatum (22±3%) and almost the whole MCA irrigated cortex area (67±6%)). 30’ t -MCAO did not produce stroke in the control group. HBO2 and HET0016 treatment equally significantly reduced size brain infarct compared to control. Combined treatment with HET0016 and HBO2 provided no significant additive effect compared to HET0016 treatment only, regardless of administration method. mRNA of Cyp2J3 was significantly increased in all study groups compared to control, and mRNA of Cyp2C11 was significantly increased in multiple HBO2 and HET0016 pretreatmen+HBO2 groups compared to control. Conclusion: Diabetic rat stroke model should be different from non-diabetic, because female type-1 diabetic SD rats are highly sensitive to brain ischemia and it is necessary to significantly shorten duration of t-MCAO, optimally to 30’. In diabetic female SD rats HBO2 and HET0016 are highly effective stroke treatments, suggesting involvement of CYP450 metabolites in this therapeutic effect.