Function In Rabbits Research Articles

Effects of right stellate ganglion block on expression of .BETA.3-adrenoceptor in rabbits with heart failure

Objective To evaluate the effects of the right stellate ganglion block on the expression of β3adrenoceptor (β3-AR) in rabbits with heart failure.Methods Forty-eight Japanese white rabbits of both sexes,weighing 2.5-3.0 kg,were randomly divided into 3 groups (n =16 each):sham operation group (group S),heart failure group (group HF) and right stellate ganglion block group (group RSGB).Heart failure was induced by occlusion of left anterior descending branch of coronary artery and confirmed by ultrasonic cardiography 4 weeks later.A PE-10 catheter was inserted into the right stellate ganglion for administration of drugs.0.25％ bupivacaine 2 ml was injected through the catheter once a day for 2 weeks in group RSGB,while the equal volume of normal saline was injected instead of bupivacaine in S and HF groups.The left ventricular end-diastolic diameter (LVEDD),left ventricular end-systolic diameter (LVESD),ejection fraction (EF) and left ventricular fractional shortening (LVFS) were measured at 1 day before ligation (T0),before catheter insertion (T1),before 8th administration (T2),and 1 day after the last administration (T3).Eight rabbits were sacrificed at T1 and T3 in each group and myocardial specimens were obtained from the apex of the left ventricle for determination of the expression of β3-AR by Western blot.Results Compared with group S,the LVEDD and LVESD were significantly enlarged and LVEF and LVFS were decreased at T1-3,and the expression of β3-AR was up-regulated at T1,3 in groups HF and RSGB (P ＜ 0.05).Compared with group HF,the LVEDD and LVESD were significantly decreased,LVEF and LVFS were increased,and the expression of β3-AR was significantly down-regulated at T3 in group RSGB (P ＜ 0.05).Conclusion The right stellate ganglion block can improve the cardiac function of rabbits with heart failure through down-regulating the expression of β3-AR in myocardium. Key words: Stellate ganglion ; Nerve block ; Heart failure ; Heart function tests; Receptors, adrenergic, beta-3

The timing of infusion of hypertonic saline to exert protective effect on intestinal barrier function in the rabbit with intestinal ischemia/reperfusion injury

To study the timing of infusion of hypertonic saline solution (HTS) to exert its protective effect on intestinal barrier function in rabbits with intestinal ischemia/reperfusion (I/R) injury. Seventy-two rabbits were randomly divided into four groups (each n=18): sham operation group, I/R group, HTS pretreatment group and HTS delayed treatment group. The intestinal I/R models were produced by blocking the superior mesenteric artery (SMA) for 1 hour followed by release of the SMA. 7.5% HTS (6 ml/kg) was infused in HTS pretreatment group 5 minutes before release of SMA, and HTS was infused in delayed treatment group 2 hours after reperfusion and finished in 5 minutes. Levels of D-lactic acid (D-Lac), lipopolysaccharide (LPS), tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10) were determined before ischemia and 2, 4, 6 hours after reperfusion. The levels of malonaldehyde (MDA), superoxide dismutase (SOD), myeloperoxidase (MPO) in intestinal tissues of 8 rabbits in each group were measured at 6 hours after reperfusion. Meanwhile the intestinal morphological changes were observed, and the Chin score, which reflected the degree of injury to intestinal mucosa was calculated. Compared with sham operation group, D-Lac, LPS, TNF-α and IL-10 in I/R group were significantly increased from 2 hours after reperfusion (D-Lac: 18.91 ± 3.46 mg/L vs. 3.92 ± 0.61 mg/L, LPS: 869 ± 85 EU/L vs. 422 ± 27 EU/L, TNF-α: 23.80 ± 4.22 μg/L vs. 3.65 ± 0.51μg/L, IL-10: 8.90 ± 2.75 μg/L vs. 2.53 ± 0.80 μg/L, all P<0.05); MDA, MPO and Chiu score were significantly increased (MDA: 398 ± 28 nmol/mg vs. 173 ± 20 nmol/mg, MPO: 465 ± 52 mU/mg vs. 183 ± 25 mU/mg, Chiu score: 4.36 ± 0.52 vs. 0.38 ± 0.22, all P<0.05), while SOD decreased significantly (35 ± 9 U/mg vs. 52 ± 8 U/mg, P<0.05). Compared with I/R group, the levels of D-Lac, LPS, TNF-α, MDA, MPO and Chiu score in HTS pretreatment group were lower (D-Lac: 11.45 ± 0.92 mg/L vs. 18.91 ± 3.46 mg/L, LPS: 455 ± 114 EU/L vs. 869 ± 85 EU/L, TNF-α: 10.32 ± 2.11 μg/L vs. 23.80 ± 4.22 μg/L, MDA: 221 ± 21 nmol/mg vs. 398 ± 28 nmol/mg, MPO: 271 ± 20 mU/mg vs. 465 ± 52 mU/mg, Chiu score: 1.69 ± 0.24 vs. 4.36 ± 0.52, all P<0.05), while IL-10 and SOD were significantly increased (IL-10: 14.54 ± 2.02 μg/L vs. 8.90 ± 2.75 μg/L, SOD: 90 ± 14 U/mg vs. 35 ± 9 U/mg, both P<0.05). The levels of the above indexes in HTS delayed treatment group were similar to I/R group, and the effect was lower than that in HTS pretreatment group. HTS had the protective effect on intestine suffering from I/R injury. But the protective effect was time dependent, and early treatment shows protective effect.

Effects of different fentanyl anaesthetic mixtures on cortico-adrenal function in rabbits

The involvement of the adrenal gland in short- and long-term adaptation of organisms to stress-inducing agents is known. A number of studies have shown that anaesthetics might regulate these systems...

Effects of exogenous hydrogen sulfide on brain metabolism and early neurological function in rabbits after cardiac arrest

Some of the neuroprotective effects of hydrogen sulfide (H(2)S) have been attributed to systemic hypometabolism and hypothermia. However, systemic metabolism may vary more dramatically than brain metabolism after cardiac arrest (CA). The authors investigated the effects of inhaled exogenous hydrogen sulfide on brain metabolism and neurological function in rabbits after CA and resuscitation. Anesthetized rabbits were randomized into a sham group, a sham/H(2)S group, a CA group, and a CA/H(2)S group. Exogenous 80 ppm H(2)S was administered to the sham/H(2)S group and the CA/H(2)S group which suffered 3 min of untreated CA by asphyxia and resuscitation. Effects on brain metabolism (cerebral extraction of oxygen (CEO(2)), arterio-jugular venous difference of glucose [AJVD(glu)] and lactate clearance), S100B, viable neuron counts, neurological dysfunction score, and survival rate were evaluated. CEO(2), AJVD(glu), and lactate increased significantly after CA. Inhalation of 80 ppm H(2)S significantly increased CEO(2) (25.04 ± 7.11 vs. 16.72 ± 6.12 %) and decreased AJVD(glu) (0.77 ± 0.29 vs. 1.18 ± 0.38 mmol/L) and lactate (5.11 ± 0.43 vs. 6.01 ± 0.64 mmol/L) at 30 min after resuscitation when compared with the CA group (all P < 0.05). In addition, neurologic deficit scores, viable neuron counts, and survival rate were significantly better whereas S100B was decreased after H(2)S inhalation. The present study reveals that inhalation of 80 ppm H(2)S reduced neurohistopathological damage and improves early neurological function after CA and resuscitation in rabbits. The increased CEO(2) and decreased AJVD(glu) and enhanced lactate clearance may be involved in the protective effects.

Assessment of the systemic effects of low-level laser therapy (LLLT) on thyroid hormone function in a rabbit model

The aim of this study was to assess the effects of low-level laser therapy (LLLT) applied to a dental extraction socket on thyroid gland function in a rabbit model, based on serum triiodothyronine and thyroxine levels. Sixteen male New Zealand rabbits were randomly distributed into two groups: a control group (non-irradiated animals) and an experimental group (irradiated animals: one irradiation point in the extraction socket of the lower incisor). Animals in the experimental group were irradiated with an aluminium gallium arsenide diode laser (AlGaAs; wavelength 830nm, 40mW, CW laser), for 13 days, every 48h, at a dose of 6J/cm2 per session, resulting in a total dose of 42J/cm2. Serum triiodothyronine and thyroxine levels were measured in both groups before extraction and on the last day of observation (day 15). There were no statistically significant differences between the groups in pre- and post-irradiation triiodothyronine and thyroxine values. With the irradiation protocol used in this study, LLLT did not affect thyroid function in rabbits as assessed by circulating serum triiodothyronine and thyroxine levels.

Neuroprotective effects of allicin on spinal cord ischemia–reperfusion injury via improvement of mitochondrial function in rabbits

Allicin, the active substance of garlic, exerts a broad spectrum of pharmacological activities and is considered to have potential therapeutic applications. The present study was designed to investigate the beneficial effects of allicin against spinal cord ischemia–reperfusion (I/R) injury and its associated mechanisms. Male New Zealand white rabbits were pretreated with allicin (1, 10 and 50mg/kg) for two weeks, and exposed to infrarenal aortic occlusion-induced spinal cord I/R injury. We found that allicin significantly reduced the volume of the spinal cord infarctions, improved the histopathologic features and increased the number of motor neurons in a dose-dependent manner. This protection was associated with an improvement in neurological function, which was measured by the hind-limb motor function scores. Furthermore, allicin also significantly suppressed the accumulations of protein and lipid peroxidation products, and increased the activities of endogenous antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX) and glutathione S-transferase (GST). In addition, allicin treatment preserved the function of mitochondria respiratory chain complexes and inhibited the production of ROS and the release of mitochondrial cytochrome c in the spinal cord of this model. Collectively, these findings demonstrated that allicin exerts neuroprotection against spinal cord I/R injury in rabbits, which may be associated with the improvement of mitochondrial function.

Chemical compositions and properties of Schinus areira L. essential oil on airway inflammation and cardiovascular system of mice and rabbits

The main purpose was to investigate the effects of essential plant-oil of Schinus areira L. on hemodynamic functions in rabbits, as well as myocardial contractile strength and airways inflammation associated to bacterial endotoxin lipopolysaccharide (LPS) in mice.This study shows the important properties of the essential oil (EO) of S. areira studied and these actions on lung with significant inhibition associated to LPS, all of which was assessed in mice bronchoalveolar lavage fluid and evidenced by stability of the percentage of alveolar macrophages, infiltration of polymorphonuclear leukocytes and tumor necrosis factor-α concentration, and without pathway modifications in conjugated dienes activity. Clinical status (morbidity or mortality), macroscopic morphology and lung/body weight index were unaffected by the administration of the EO S. areira.Furthermore, the ex vivo analysis of isolated hearts demonstrated the negative inotropic action of the EO of S. areira in a mice model, and in rabbits changes in the hemodynamic parameters, such as a reduction of systolic blood pressure. We conclude that EO S. areira could be responsible for modifications on the cardiovascular and/or airway parameters.

Retinal Function and Morphology in Rabbit After Intravitreal Injection of VEGF Inhibitors

Purpose/Aim: To explore changes in morphology and function in the rabbit retina after intravitreal high-dose injection of three commonly used VEGF inhibitors.Materials and methods: Forty-eight rabbits of mixed strain (6 months of age, body weight ≈ 3 kg) were randomized into four groups (n = 12). They were examined with full-field electroretinography (ERG) and with multifocal electroretinography (mf ERG) prior to drug exposure. The rabbits were then injected intravitreally with bevacizumab, ranibizumab, pegaptanib, or with a balanced saline solution. The dose of VEGF inhibitor was chosen to achieve a vitreous concentration approximately three times higher than the one clinically used in the adult human eye. ERG was then performed 8 weeks postinjection, and mf ERG 9 weeks postinjection. After 9 weeks, the rabbits were sacrificed and the sectioned retina was studied. Immunohistochemical analysis was performed of rods, cones, rod bipolar cells, horizontal cells, and amacrine cells.Results: Rabbits injected with VEGF inhibitors all showed significantly lower amplitude of the dark-adapted b-wave rod-mediated response to dim light, compared to the rabbits injected with BSS. The a wave (reflecting photoreceptor function) in the response to single flash white light was however not affected. Immunohistochemistry revealed a significant reduction in PKC labeling of rod bipolar cells in pegaptanib and ranibizumab injected eyes whereas bevacizumab injected eyes displayed normal PKC labeling. No apparent morphological change was seen with markers for remaining retinal cells.Conclusions: Our results indicate that the use of high-dose intravitreal VEGF inhibitors in the rabbit eye affects rod-mediated retinal function and PKC expression in rod bipolars cells for at least 9 weeks after drug administration. The three VEGF inhibitors influence the retina slightly differently. These results are important for the understanding of drug action and when devising therapeutical strategies in new areas such as retinopathy of prematurity where vitreous volume is significantly lower compared to the adult eye.

Effects of different fluids on cardiac function of rabbits with thermal burn-induced shock

Objective To study the effects of different fluids on on cardiac function of rabbits with thermal burn-induced shock Methods 40 rabbits were randomly divided into four groups,group Ⅰ:control group (without thermal injury),group Ⅱ:0.9％ NaC1 solution,group Ⅲ:lactated Ringer's solution,group Ⅳ:acetated Ringer's injection.The infusion rate was 0.33 ml/kg/％(area percentage of heat injury)/h in 4 h when the thermal injury of rabbit body surface area was 25％ to 30％.Cardiac function were measured in each group by working heart preparation in vitro model.Results Cardiac output(CO)[ (85±9),(90±9),(102±11),(103±10),(99±10),(101±11) ml/min],dp/dt[(1 200±110),(1 350±125),(1 210±100),(1 200±115),(1 150±120),(1 000±95) mmHg/s (1 mm Hg=0.133 kPa)],-dp/dt[(1 000±95),(1 150±100),(1 110±105),(1 100±110),(1 050±105),(1 000±100) mm Hg/s]in group Ⅱ were significantly lower than those in group Ⅰ (P＜0.05,P＜0.01 ),and these parameters were improved in group Ⅲ,but could not return to the levels in group.The parameters in group Ⅳ were similar to those in group Ⅰ (P＞0.05).Stroke work [ (21.2±2.3 ),(23.3±2.1),(27.2±2.3),(26.3±2.4),(26.1±3.2),(25.1±2.3) Q·mm Hg·bpm-1] and aortic peak systolic pressure[(55±4),(54±4),(56±4),(55±4),(53±4),(53±5) mm Hg] in group Ⅱ were significantly lower than those of group Ⅰ (P＜0.05,P＜0.01) while these parameters in group Ⅲ and Ⅳ were not different,compared to those of group. Conclusions Compound electrolyte solution infusion can improve cardiac function of rabbits with thermal burn-induced shock. Key words: Acetated ringer's injection; Lactated ringer's injection; Cardiac function; Rabbit

Vascular Hyporeactivity to Angiotensin II and Noradrenaline in a Rabbit Model of Obesity

This study was conducted to explore the vascular reactivity of angiotensin II and noradrenaline and their relationship with endothelial function in rabbits fed a high-fat diet (HFD). The animals were fed either an HFD or regular chow [control diet (CD)]. After 12 weeks, the rabbits fed the HFD showed higher blood pressure, body weight, and insulin levels. Glucose tolerance was impaired and positively related to blood pressure. An endothelium-independent decrease of the sensitivity to angiotensin II [pD2 endothelium-intact aortic rings (E+) in CD: 8.02 ± 0.07 vs. HFD: 7.60 ± 0.01; pD2 endothelium-removed aortic rings (E-) in CD: 8.16 ± 0.11 vs. HFD: 7.83 ± 0.16] and noradrenaline (pD2 E+ in CD: 6.36 ± 0.06 vs. HFD: 5.29 ± 0.06; pD2 E- in CD: 6.11 ± 0.08 vs. HFD: 5.80 ± 0.08) was found. Noradrenaline desensitized the angiotensin II response (pD2 with noradrenaline pretreatment in E+: 7.03 ± 0.16; in E-: 7.10 ± 0.02), but angiotensin II did not change the noradrenaline response. Acetylcholine maximal relaxation and basal nitric oxide (NO) release were comparable in both diet groups. The efficacy of angiotensin II (Rmax CD: 4604 ± 574 mg vs. HFD: 3251 ± 533 mg) and noradrenaline (Rmax CD: 11,675 ± 804 mg vs. HFD: 7975 ± 960 mg) was reduced in E+. L-N-nitroarginine methyl ester (L-NAME) recovered the efficacy of noradrenaline (Rmax L-NAME: 12,015 ± 317 mg). In contrast, L-NAME had no effect on the angiotensin II response. Noradrenaline enhanced NO levels, but angiotensin II did not. Therefore, NO was associated with hyporeactivity to noradrenaline. The resting potential was more negative in E+, and the endothelium diminished the angiotensin II-induced depolarization. These findings demonstrated that the crosstalk and the endothelium may induce hyporeactivity to angiotensin II and noradrenaline as a mechanism to compensate the increase in the blood pressure in HFD-induced obesity.

The Effect of Aqueous Leaf Extract of Vernonia amygdalina on Liver Function in Rabbits

The Effect of Aqueous Leaf Extract of Vernonia amygdalina on Liver Function in Rabbits

132 A NEW APPROACH TO ASSESS OVARIAN STRUCTURES IN LIVE RABBITS: SURGICAL TRANSLOCATION AND ULTRASOUND BIOMICROSCOPY

For the purpose of determining factors associated with ovulation induction in rabbits, there is a need to examine the ovaries in a serial fashion. To this end, a study was designed to develop an approach that would permit serial evaluation of ovarian structures in vivo using ultrasound biomicroscopy (UBM) while preserving ovarian function in rabbits. The use of UBM has enabled characterisation of ovarian dynamics in live mice and has recently been validated for assessing structures in excised rabbit ovaries (Cervantes et al. 2011 Reprod. Fertil. Dev. 23, 183–184). However, acoustic impedance of the body wall prevented acquisition of high-quality ovarian images in vivo by transabdominal UBM in rabbits. Female New Zealand White rabbits (5 months old; n = 12) underwent surgical ovarian translocation. Each ovary was exteriorized through a lateral flank incision on the respective sides, without compromising vascular supply. The mesovarium at each pole of the ovary was transfixed to the muscle layers of the abdominal wall to keep the ovary in a subcutaneous position. Finally, the subcutaneous and skin layers were closed. No postoperative complications were observed. The surgical site was allowed to heal for 2 weeks and the skin sutures were removed before UBM was attempted. The rabbits were wrapped in a towel for restraint without sedation. Acoustic gel was applied to the shaved skin over the translocated ovary and ovarian structures were imaged transcutaneously by UBM using a 25-MHz transducer on 3 consecutive days. Both ovaries were clearly distinguished in all 12 rabbits during each examination. Antral follicles ranging from 0.6 to 3.1 mm were detected and the number of follicles ≥0.6 mm per pair of ovaries ranged from 7 to 18. Data were analysed by one-way ANOVA. The number and diameter of follicles ≥0.6 mm per rabbit did not differ among the 3 examinations (mean ± s.e.m.; 11.0 ± 0.82, 11.8 ± 0.85 and 12.3 ± 0.75 follicles and 1.3 ± 0.07, 1.3 ± 0.07 and 1.4 ± 0.07 mm, respectively). However, follicles ≥2 mm in diameter were detected in 3 out of 12 rabbits on the first and second days and in 5 out of 12 rabbits on the third day. One or more corpora lutea were detected in the same 2 rabbits (2/12) during each of the 3 examination days. Two months after surgery, ovarian structures were clearly discernible by UBM in 11 of 24 translocated ovaries. Image deterioration was attributed to the attenuation of sound waves associated with increased skin thickness and growth of subcutaneous fat and connective tissue around the ovary, assessed at necropsy. In summary, translocated ovaries continued to function in their new location and transcutaneous UBM permitted serial visualisation of ovarian structures in live rabbits. Therefore, this new approach provides a nonterminal alternative for repetitive examination of rabbit ovaries and is particularly appropriate for experiments involving factors associated with ovulation induction in rabbits. This research was supported by the Natural Sciences and Engineering Research Council of Canada.

Effects of Epidural Capsaicin on Nociceptive Threshold and Neurological Functions in Rabbits

Capsaicin, as a principle active component of Chili peppers, is popularly consumed by many people around the world. Whether capsaicin-induced neuropathy alters the function of sensory neurons is still unknown. The objectives of this study were to determine the effects of epidural capsaicin on nociceptive threshold and neurological functions in a rabbit model. An intrathecal injection system was set up using a rabbit model. Rabbits were treated with capsaicin at doses of 0.04, 0.10, and 0.20 mg/kg once. The changes in neurological functions and morphology of the spinal cord and spinal nerve roots were determined within 24 hours. Changes in the nociceptive threshold in the hind limbs of the rabbits were observed for 30 days. Capsaicin's effect on the changing neurological functions was evaluated by the neurological functional scores. The structural changes of spinal cord and spinal nerve roots were observed by hematoxylin and eosin staining and transmission electron microscopy. The nociceptive threshold changes in the rabbits were measured by the responding time for pain induced by a thermostimulation. The results showed that capsaicin reversed changes in the neurological function of rabbit hindlimbs. In the 0.10 and 0.20 mg/kg groups, structural abnormalities were found in the rabbit's spinal nerves. Capsaicin also significantly increased the pain threshold in rabbits when compared with the control group (P < 0.05 or P < 0.01). The maximum values of pain threshold were found in the 0.10 mg/kg capsaicin group after 3 days of capsaicin treatment. With the exception of a potential toxicity, capsaicin may be a potential candidate agent for providing pain relief of both neuropathic and nociceptive conditions.

Therapy with cardiac contractility modulation electrical signals improves left ventricular function in rabbits with heart failure

ObjectivesThis study examined the effects of short-term delivery of cardiac contractility modulation (CCM) electric signals on LV function in rabbits with HF.MethodsIn one study, rabbits with the transverse ascending aorta...

Effects of chronic sympatho-inhibition on renal excretory function in renovascular hypertension

Treatment of renovascular hypertension with drugs that directly target the renin-angiotensin system may compromise glomerular filtration and renal excretory function, leading to renal failure. Centrally acting sympathoinhibitory agents also inhibit the renin-angiotensin system, so we determined whether this treatment modality alters renal excretory function in rabbits with renovascular hypertension. Rabbits were equipped with bilateral renal artery flow probes and a renal nerve electrode. Hypertension was induced with a renal artery clip (2K1C) or rabbits were sham-clipped. After 2 weeks, a subcutaneous minipump was implanted to deliver rilmenidine (2.5 mg/kg per day) or vehicle for 3 weeks. Haemodynamic variables and renal function were studied under control conditions and during intravenous infusion of isotonic saline (154 mmol/l NaCl) at increasing rates of 4, 12 and 36 ml/kg per hour. Mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) were greater in 2K1C rabbits than sham-clipped rabbits, but total urine flow, sodium excretion and glomerular filtration rate were similar in the two groups. In 2K1C rabbits, rilmenidine reduced MAP to close to control levels and reduced RSNA (40%), but did not significantly alter basal renal blood flow, glomerular filtration rate, urine flow or sodium excretion. The natriuretic response to isotonic saline load in 2K1C rabbits was not significantly altered by rilmenidine. These observations show that chronic treatment of rabbits with renal artery stenosis with a centrally acting sympathoinhibitory agent, despite normalizing MAP, does not compromise renal excretory function. Thus, this treatment modality may be particularly useful in renovascular hypertension.

Protective effects of ischemic postconditioning on intestinal mucosa barrier function in rabbits with crush injury of hind limb: an experimental study

Objective To explore the protective effects of two types of ischemic postconditioning (IP) on intestinal mucosa barrier in rabbits with crush injury of the hind limb. Methods This study was conducted between August and December 2008 in the Department of Trauma Surgery, Daping Hospital, Third Military Medical University, Chongqing, China. The model of crush injury to the hind limb of rabbits was firstly developed by a 25 kg object with the right hind limbs fixed by wooden splints, and then two types of IP were established, including occluding/opening the common iliac artery and vein alternatively (traditional IP, IP A) and binding/loosening the proximum of the injured hind limb alternatively (modified IP, IP B). Thirty-six male New Zealand white rabbits were randomly divided into three groups: IP A group, IP B group and control group, with 12 rabbits in each group. The serum levels of diamine oxidase (DAO) and intestinal fatty acid-binding protein (I-FABP) were detected at 2, 6, 12 and 24 hours after injury. Pathological changes of ileum were examined at 24 hours after injury. Results The serum levels of I-FABP at 2, 6, 12 and 24 hours after injury in both IP A and IP B groups had a significant decrease, compared with control group. DAO levels also showed the same change trend at 2 and 6 hours after injury, but showed no significant difference between two IP groups. No difference in pathological changes of ileum was found among the three groups. Conclusions IP can protect intestinal mucosa barrier function on the model of hind limb crush injury in rabbits. Meanwhile the modified IP B shows the same protection as the traditional IP A, and is worth applying in clinic.

GnRH agonist active immunization influences ovarian development and GnRH receptor mRNA expression levels of pituitary in Japanese white rabbits ( Oryctolagus cuniculus)

The present study was conducted to assess the effects of active immunization against the gonadotropin-releasing hormone agonist (GnRHa) on ovary development and GnRH receptor mRNA expression levels in pituitary in Japanese white rabbits ( Oryctolagus cuniculus). Twenty-four three-month-old rabbits were randomly divided into four groups (n = 6). The animals were subcutaneously injected with 100 μg of GnRHa (alarelin) antigen in experimental group I (EG-I), 100 μg in experimental group II (EG-II) and 50 μg in experimental group III (EG-III) respectively. Alarelin antigens were re-injected in EG-II and EG-III with the same dosage on 20 days. CG was blank. The samples of ovaries and uteri were collected aseptically at the end of the experiment (70 days). Tissue slices were observed under light and electron microscopes. Serum anti-GnRH antibody titers and concentrations of FSH and LH were measured with ELISA. The anti-GnRH antibody titers reached the peak levels respectively at 30 days in EG-I (1:800), at 40–50 days in EG-II (1:1600) and at 40–50 days in EG-III (1:800). From 40 to 70 days, anti-GnRH antibody titers in EG-II were higher than that in EG-I and EG-III ( p < 0.05). The highest FSH levels in EG-II and EG-III were detected on 40 days. FSH level in EG-II was higher than those in EG-I, CG ( p < 0.01) and EG-III ( p < 0.05) on 40 days. There was no significant difference in FSH levels between EG-I and CG. Serum LH concentrations in EG-II and EG-III reached the peak levels on 50 days and 40 days, LH level in EG-II exceeded other 3 groups on 50 days ( p < 0.05). Real-time quantitative PCR analysis indicated that the levels of FSH-β mRNA and GnRH-R mRNA in pituitary significantly declined, while LH-β mRNA increased at 70 days following alarelin antigen treatment. The results also showed that alarelin antigen treatment improves the development of ovaries, follicles and uteri in Japanese white rabbits. Alarelin antigen treatment and re-injection with 100 μg dose had better effects than 50 μg treatment. This may have significance for the development of novel GnRH-based techniques in regulative functions in rabbits.

Plasma nitric oxide and left ventricular function in rabbits after cardiac lymphatic obstruction

This study was designed to investigate the effect of cardiac lymphatic obstruction on plasma nitric oxide (NO) and left ventricular function. The plasma NO was measured in study group (n = 21) and control group rabbits (n = 12) before, and 3, 7, 14, 30 and 90 days after the obstruction of cardiac lymphatic vessels. Left ventricular ejection fraction was measured with echocardiography. There was a significant reduction in the left ventricular ejection fraction following the lymphatic obstruction (0.72±0.02 vs. 0.61±0.02, p<0.01). Plasma NO in the control group remained unchanged during the observation period (54.2±4.4 vs. 52.0±4.2 μmol/L, p>0.05). In the study group, there was a small but significant increase in the plasma NO on day 3, 7 and 14 following the lymphatic obstruction (52.3±4.1 vs. 73.4±5.9 μmol/L, p<0.01). The plasma NO returned to the baseline levels on day 30 but reduced to 44.9±3.6 μmol/L on 90 days after the lymphatic obstruction (p<0.05). In conclusion, cardiac lymphatic obstruction was associated with a significant reduction in left ventricular function. It was also associated with an increase in the plasma NO in the first 2 weeks but there was a significant reduction in the NO levels three months after the lymphatic obstruction.

Role of blood flow in carotid body chemoreflex function in heart failure

Peripheral chemoreflex sensitivity is potentiated in clinical and experimental chronic heart failure (CHF). Blood supply to tissues is inevitably reduced in CHF. However, it remains poorly understood whether the reduced blood flow is the cause of increased peripheral chemoreflex sensitivity in CHF. This work highlights the effect of chronically reduced blood flow to the carotid body (CB) on peripheral chemoreflex function in rabbits. In pacing-induced CHF rabbits, blood flow in the carotid artery was reduced by 36.4 ± 5.2% after 3 weeks of pacing. For comparison, a similar level of blood flow reduction was induced by carotid artery occlusion (CAO) over a similar 3 week time course without pacing. CB blood supply was reduced by similar levels in both CHF and CAO rabbits as measured with fluorescent microspheres. Compared with sham rabbits, CAO enhanced peripheral chemoreflex sensitivity in vivo, increased CB chemoreceptor activity in an isolated CB preparation and decreased outward potassium current (Ik) in CB glomus cells to levels similar to those that were observed in CHF rabbits. In CAO CB compared to sham, neural nitric oxide (NO) synthase (nNOS) expression and NO levels were suppressed, and angiotensin II (Ang II) type 1 receptor (AT1-R) protein expression and Ang II concentration were elevated; these changes were similar to those seen in the CB from CHF rabbits. A NO donor and AT1-R antagonist reversed CAO-enhanced chemoreflex sensitivity. These results suggest that a reduction of blood flow to the CB is involved in the augmentation of peripheral chemoreflex sensitivity in CHF.

Dual energy CT ventilation imaging after aerosol inhalation of iodinated contrast medium in rabbits

Purpose To assess the feasibility of dual energy CT (DECT) after aerosol inhalation of iodinated contrast medium for the evaluation of ventilation function in rabbits with airway obstruction. Materials and methods The study was approved by our institutional animal experimental committee and performed according to animal care guidelines. Airway obstruction was created by injecting gelatin sponge into the right bronchus of 6 New Zealand rabbits. One additional rabbit served as control without airway obstruction. All 7 rabbits then underwent inhalation of aerosol iodinated contrast medium for 5 min, followed by DECT of the lungs from which ventilation CT images were created. CT number and overlay value (calculated iodine enhancement on the ventilation images in hounsfield unit) of the obstructed and non-obstructed lung lobes were measured at 80-kVp, 140-kVp, and weighted average 120-kVp. Immediately after DECT scan, the rabbits were sacrificed, the lungs were removed and detailed pathological examination of the locations and parenchymal changes of the obstructed lung lobes were performed and correlated with DECT ventilation imaging findings. Results Data from one rabbit with airway obstruction were excluded because of post-procedure pneumatothorax. Seventeen normal lung lobes without airway obstruction proven by histopathology had nearly homogeneous ventilation, while 13 abnormal lung lobes had ventilation defects on DECT ventilation images. CT numbers and overlay values of the normal (CT number, −737.77 ± 71.46 HU, −768.84 ± 73.86 HU, −731.86 ± 65.92 HU for 140-kVp, 80-kVp, and weighted average 120-kVp; overlay value, 46.58 ± 19.49 HU) and abnormal lung lobes (CT number, −183.58 ± 173.37 HU, −124.93 ± 242.23 HU, −166.07 ± 191.57 HU for 140-kVp, 80-kVp, and weighted average 120-kVp; overlay value, 0.00 ± 0.00 HU) were significantly different at 80-kVp, 140-kVp, and weighted average 120-kVp ( P < 0.001 for all). Diffuse hemorrhage, inflammatory cell infiltration, and exudation were observed at histopathology in the obstructed lung lobes. Conclusions It is feasible to study regional lung ventilation function using DECT after aerosol inhalation of iodinated contrast medium in rabbit. The safety of inhalation of iodine contrast medium is unknown, and has to be investigated further before use of this new method in humans.