Treatment of traumatic brain injury with 17α-ethinylestradiol-3-sulfate in a rat model.

OBJECTIVE 17α-ethynylestradiol-3-sulfate (EE-3-SO4) is a highly water-soluble synthetic estrogen that has an extended half-life (∼ 10 hours) over that of naturally occurring estrogen (∼ 10 minutes). In this study, EE-3-SO4 was evaluated in a lateral fluid percussion-induced traumatic brain injury (TBI) model in rats. METHODS A total of 9 groups of Sprague-Dawley rats underwent craniectomy. Twenty-four hours later, lateral fluid percussion was applied to 6 groups of animals to induce TBI; the remaining 3 groups served as sham control groups. EE-3-SO4 (1 mg/kg body weight in 0.4 ml/kg body weight) or saline (vehicle control) was injected intravenously 1 hour after TBI; saline was injected in all sham animals. One day after EE-3-SO4/saline injection, intracranial pressure (ICP), cerebral perfusion pressure (CPP), and partial brain oxygen pressure (PbtO2) were measured in Groups 1-3 (2 TBI groups and 1 sham group), and brain edema, diffusion axonal injury, and cerebral glycolysis were assessed in Groups 4-6 using MRI T2 mapping, diffusion tensor imaging (DTI), and FDG-PET imaging, respectively. Four days after dosing, the open-field anxiety of animals was assessed in Groups 7-9 by measuring the duration that each animal spent in the center area of an open chamber during 4 minutes of monitoring. RESULTS EE-3-SO4 significantly lowered ICP while raising CPP and PbtO2, compared with vehicle treatment in TBI-induced animals (p < 0.05). The mean size of cerebral edema of TBI animals treated with EE-3-SO4 was 25 ± 3 mm3 (mean ± SE), which was significantly smaller than that of vehicle-treated animals (67 ± 6 mm3, p < 0.001). Also, EE-3-SO4 treatment significantly increased the fractional anisotropy of the white matter in the ipsilateral side (p = 0.003) and cerebral glycolysis (p = 0.014). The mean duration that EE-3-SO4-treated animals spent in the center area was 12 ± 2 seconds, which was significantly longer than that of vehicle-treated animals (4 ± 1 seconds; p = 0.008) but not different from that of sham animals (11 ± 3 seconds; p > 0.05). CONCLUSIONS These data support the clinical use of EE-3-SO4 for early TBI treatment.

Salutary Effects of Estrogen Sulfate for Traumatic Brain Injury.

Estrogen plays an important role as a neuroprotector in the central nervous system (CNS), directly interacting with neurons and regulating physiological properties of non-neuronal cells. Here we evaluated estrogen sulfate (E2-SO4) for traumatic brain injury (TBI) using a Sprague-Dawley rat model. TBI was induced via lateral fluid percussion (LFP) at 24 h after craniectomy. E2-SO4 (1 mg/kg BW in 1 mL/kg BW) or saline (served as control) was intravenously administered at 1 h after TBI (n=5/group). Intracranial pressure (ICP), cerebral perfusion pressure (CPP), and partial brain oxygen pressure (pbtO2) were measured for 2 h (from 23 to 25 h after E2-SO4 injection). Brain edema and diffuse axonal injury (DAI) were assessed by diffusion tensor imaging (DTI), and cerebral glycolysis was measured by (18)F-labeled fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging, at 1 and 7 days after E2-SO4 injection. E2-SO4 significantly decreased ICP, while increasing CPP and pbtO2 (p<0.05) as compared with vehicle-treated TBI rats. The edema size in the brains of the E2-SO4 treated group was also significantly smaller than that of vehicle-treated group at 1 day after E2-SO4 injection (p=0.04), and cerebral glycolysis of injured region was also increased significantly during the same time period (p=0.04). However, E2-SO4 treatment did not affect DAI (p>0.05). These findings demonstrated the potential benefits of E2-SO4 in TBI.

Effects of systemic chlorogenic acid on random-pattern dorsal skin flap survival in diabetic rats.

There has been considerable interest in understanding the effects of antioxidants in flap survival during diabetes. Previous studies showed that chlorogenic acid (CGA) exhibits potent antioxidant effects. We aimed to determine the effects of systemic CGA treatment on skin flap survival in an experimental random-pattern dorsal skin flap model in diabetic rats. Twenty-eight male Wistar rats were divided into four groups: phosphate buffered saline (PBS)-treated or CGA-treated nondiabetic rats, PBS-treated or CGA-treated diabetic rats. Diabetes was induced by streptozotocin (45 mg/kg). Caudally based bipedicled dorsal skin flaps were elevated. CGA (100 mg/kg) or PBS (mL/kg; as vehicle) was administered intraperitoneally once daily. On postoperative day 7, flap survival, regional blood perfusion and microangiography were evaluated. The malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD) and nitric oxide (NO) levels were evaluated from the flap tissue. Capillary density and vascular endothelial growth factor (VEGF) expression were assessed. Harmful effects of diabetes on flap survival were observed. CGA attenuated these effects and allowed greater survival and blood perfusion. CGA decreased MDA and NO levels and increased GSH and SOD levels. CGA elevated capillary density and VEGF expression. This study showed that peripherally administered CGA significantly improved flap survival in diabetic and nondiabetic rats.

Hemostatic effect of a chitosan linear polymer (Celox®) in a severe femoral artery bleeding rat model under hypothermia or warfarin therapy.

BACKGROUND: In this study, the hemostatic efficacy of Celox® in rats under hypothermia or warfarin treatment was investigated. METHODS: A total of forty-eight Sprague-Dawley female rats weighing 200-350 g were used in the study. Six experimental study groups were designed, as follows: Group 1: Normothermia + compression; Group 2: normothermia + Celox®; Group 3: hypothermia + compression; Group 4: hypothermia + Celox®; Group 5: normothermia + warfarin + compression; and Group 6: normothermia + warfarin + Celox®. RESULTS: Celox® provided effective hemorrhage control in all three tested groups. There was a statistically significant difference between compression and Celox® implementation in all groups in terms of hemostasis (p-values for the normothermia, hypothermia and warfarin groups were p<0.05, p<0.01 and p<0.01, respectively). Furthermore, the compression numbers were significantly lower in all of the groups that received Celox ® than in those in which compression alone was applied (p-values for the normothermia, hypothermia and warfarin groups were p<0.01, p<0.01 and p<0.001, respectively). CONCLUSION: Celox® provides effective hemorrhage control under conditions of normothermia, hypothermia and use of the oral anticoagulant agent warfarin.

Effect of peripherally-injected glucagon-like peptide-1 on gastric mucosal blood flow.

The aim of this study was to investigate the mechanisms involved in the effect of glucagon-like peptide-1 (GLP-1) on the decrease in gastric mucosal blood flow (GMBF) induced by intragastric ethanol. After preparation of the stomach for GMBF recording, a probe was placed to the gastric mucosa and basal GMBF recordings were obtained by a laser Doppler flowmeter after a 30-minute stabilization period. Following GLP-1 (1000 ng/kg; i.p.) injection, 1 ml of absolute ethanol was applied to the gastric chamber and GMBF was recorded continuously during a 30-minute period. GLP-1 (1000 ng/kg; i.p.) prevented the decrease in GMBF induced by ethanol. Nitric oxide (NO) synthase inhibitor L-NAME, (30 mg/kg; s.c.), calcitonine gene-related peptide (CGRP) receptor antagonist CGRP-(8-37) (10 microg/kg; i.p.), and cyclooxygenase inhibitor indomethacin (5 mg/kg; i.p.) all inhibited the GMBF-improving effect of GLP-1. We concluded that, NO, CGRP and prostaglandins may be involved in the effect of peripherally-injected GLP-1 on GMBF reduction induced by intraluminal ethanol.

Peripheral GLP-1 gastroprotection against ethanol: the role of exendin, NO, CGRP, prostaglandins and blood flow.

The aim of this study was to investigate the effects of peripherally injected glucagon like peptide-1 (GLP-1) on ethanol-induced gastric mucosal damage and the mechanisms included in the effect. Absolute ethanol was administered through an orogastric cannula right after the injection of GLP-1 (1, 10, 100, 1000 or 10,000 ng/kg; i.p.). The rats were decapitated an hour later, the stomachs removed and the gastric mucosal damage scored. 1000 ng GLP-1 inhibited gastric mucosal damage by 45% and 10,000 ng GLP-1 by 60%. The specific receptor antagonist exendin-(9-39) (2500 ng/kg; i.p.), calcitonin gene related peptide (CGRP) receptor antagonist CGRP-(8-37) (10 microg/kg; i.p.), nitric oxide (NO) synthase inhibitor l-NAME (30 mg/kg; s.c.) and cyclooxygenase inhibitor indomethacin (5 mg/kg; i.p.) inhibited the preventive effect of GLP-1 on ethanol-induced gastric mucosal damage. GLP-1 also prevented the decrease in gastric mucosal blood flow caused by ethanol when administered at gastroprotective doses (1000 and 10,000 ng/kg; i.p.). In conclusion, GLP-1 administered peripherally prevents the gastric mucosal damage caused by ethanol in rats. CGRP, NO, prostaglandin and gastric mucosal blood flow are thought to play a role in this effect, mediated through receptors specific to GLP-1.

Central effects of glucagon-like peptide-1 on cold-restraint stress-induced gastric mucosal lesions.

BACKGROUND/AIMS: Intracerebroventricular (i.c.v.) glucagon-like peptide-1 (GLP-1) has been shown to prevent gastric mucosal lesions induced by reserpine and ethanol. Here, we aimed to investigate the effects of i.c.v. GLP-1 on stress-induced gastric mucosal lesions and the mechanisms which may mediate these effects. METHODS: Rats were equipped with intravenous and i.c.v. cannulas under ether anesthesia. To induce cold-restraint stress, rats were kept individually in wire cages, specifically prepared according to their sizes, at 7-9 degrees C for 5 hours. They were then decapitated, and their stomachs were removed and scored for mucosal damage. GLP-1 (1, 10, 100, 1000 ng/10 microl; i.c.v.) was injected 5 min before cold-restraint stress induction. Rats were pretreated with exendin-(9-39) (2.5 ng/10 microl; i.c.v. and 250 ng/kg; intraperitoneal [i.p.]), calcitonin gene-related peptide (CGRP)-(8-37) (10 microg/kg; i.p.), N(G)-nitro-L-arginine methyl ester (L-NAME) (3 mg/kg; i.v.), indomethacin (5 mg/kg; i.p.) and atropine (1 mg/kg; i.p.) to investigate mechanisms which may mediate the gastroprotective effect of GLP-1. RESULTS: GLP-1 (1000 ng/10 microl; i.c.v.) significantly prevented gastric mucosal lesions induced by cold-restraint stress (p<0.01). Intracerebroventricular (i.c.v.), but not i.p., injection of exendin-(9-39) significantly blocked the gastroprotective effect of the peptide (p<0.05). Pretreatment with CGRP-(8-37), L-NAME and indomethacin also prevented the gastroprotective effect of i.c.v. GLP-1 (p<0.05, p<0.05 and p<0.01, respectively), while pretreatment with atropine did not prevent the gastroprotective effect of the peptide. CONCLUSIONS: We conclude that i.c.v GLP-1 inhibits the gastric mucosal damage induced by cold-restraint stress via the activation of its specific receptors, and CGRP, nitric oxide and prostaglandins, but not cholinergic muscarinic receptors, mediate this effect.