Understanding the postmortem changes in concentrations of methanol in ocular matrices in rabbits

Death due to abuse and accidental ingestion of methanol is widely known around the globe. The paper presents the postmortem changes in concentrations of methanol in the vitreous humor, aqueous humor, and ocular tissues in a rabbit model in methanol intoxication. Rabbits were intoxicated with methanol at a dose of 6.3 ml/kg through oral gavage. After 3.5 h of methanol administration, the rabbits were sacrificed. Vitreous humor, aqueous humor, and ocular tissues were collected both, perimortem (immediately) and postmortem (17 h post-death). Whole blood and plasma samples were also collected to explore the correlation between levels of methanol in whole blood/plasma and ocular fluids/ocular tissues if any. All the samples were analyzed by Headspace Gas Chromatography. The analysis revealed a decrease in methanol levels at postmortem for all the matrices, except for retina-choroid than its perimortem value. For retina-choroid, no significant change in methanol levels at postmortem was found.     

MR diffusion-weighed imaging of rabbit liver

AIM: To study the techniques of MR diffusion-weighed imaging (DWI) for normal rabbit liver. METHODS: After 15 normal New Zealand white rabbits and one New Zealand white rabbit implanted with VX-2 tumor were anesthetized with 3% soluble pentobarbitone, DWI was performed respectively for different b values, repetition times (TR) or thicknesses, when other parameters were the same and magnetic resonance imaging (MRI) was performed respectively, or with different field of views (FOV) or coil when other parameters were the same. The distinction between groups was analyzed by SPSS10.0 with apparent diffusion coefficient (ADC), quality index (QI) or signal-noise ratio (SNR). RESULTS: As b value increased, liver ADC, QI and SNR of DWI became smaller and simultaneously (F=292.87, 156.1, 88.23, P<0.01). QI of DWI was high, when b value was 10, 50 or 100 respectively, but the distinction between them was insignificant; when b value was 800, QI and SNR of DWI were low. QI and SNR of DWI had no significant difference between TR=4000, 6000 and 8000. QI of DWI with 2 mm thickness was bigger than that with 5 mm thickness (t=3.04, P<0.01), but SNR of DWI with 2 mm thickness was significantly smaller (t=-17.86, P<0.01). SNR of MRI with knee joint coil was obviously bigger than that with cranium coil [t=-5.77 (T1WI) or -4.02 (T2WI), P<0.01], but QI of MRI was smaller on the contrary [t=7.10 (T1WI) or 3.97 (T2WI), P<0.01]. When FOV was enlarged gradually, SNR of MRI increased [F=85.81 (T1WI) or 221.96 (T2WI), P<0.01], but QI firstly increased, then decreased [F=68.67 (T1WI) or 69.46 (T2WI), P<0.01] and QI of MRI was the biggest when FOV was 20 cm脳15 cm. CONCLUSION: The scanning technique is very important in DWI of rabbit iiver and the overall quality of DWI with b (100 s/mm~2), thickness (2 mm), cranium coils and FOV (20 cm×15 cm) was best in our study, when other parameters were the same.     

Myocardial injury following endogenous catecholamine release in rabbits

Catecholamines (CAT) given in large doses produce cardiomyopathic changes in several animal species. This study was designed to determine if endogenous release can also induce cardiac injury. Rabbits were infused with doses of tyramine (TYR), ranging from 200 to 500 micrograms/min/kg, i.v. for 90 min. Arterial pressure and heart rate were measured, as were total CAT concentrations, blood gases, pH and glucose. Two days later the animals were killed and cardiac injury assessed using a histological scoring system. All data were compared with controls given saline. Initial CAT averaged 452 pg/ml, rose to 2890 pg/ml after starting TYR, 500 micrograms/min/kg, and remained elevated for the duration of infusion. Circulating CAT levels were a function of TYR dose, and bore a linear relationship to the histological score (P less than 0.001). Development of lesions was unaltered by beta 1 blockade with practolol, but sharply reduced by alpha blockade with phentolamine (P less than 0.01). Pretreatment with insulin also reduced lesion formation, but diabetic (alloxan) rabbits showed no greater CAT injury. It is concluded that endogenous release of CAT induces myocardial injury in the rabbit in a dose-dependent manner. This is unrelated to myocardial O2 demand, and microvascular pathology was absent. Activation of alpha adrenergic pathways is likely the dominant or exclusive mechanism.     

高脂饮食上调兔子血管内膜与血清炎性因子表达

目的:分析高脂饮食致肥胖或动脉粥样硬化兔子血管内膜白细胞介素-1β(IL-1β)和肿瘤坏死因子-α(TNF-α)水平变化。方法:12只健康新西兰大白兔,分为普通饮食组(OD组)和高脂饮食组(HFD组)。依据动脉粥样硬化造模方法,高脂饮食喂养兔8周后,获取兔子血液或颈动脉组织。检测血细胞相关参数和血液生化参数及动脉内膜的厚度,同时用ELISA检测IL-1β和TNF-α水平,Western Blot法检测血管内膜IL-1β和TNF-α蛋白的表达。比较分析两组各检测参数的差异。结果:两组兔子外周血细胞检测项目无统计学差异(P>0.05)。HFD组脂质检测指标甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)和载脂蛋白B(ApoB)均显著高于OD组(P<0.05,P<0.01),而高密度脂蛋白胆固醇(HDL-C)则显著低于OD组(P<0.05)。其它血液生化项目在两组间的水平无显著差异(P>0.05)。ELISA检测OD组血浆IL-1β和TNF-α的水平显著低于HFD组(P<0.05)。以高脂饮食喂养健康兔子发现HFD组兔血管内膜的厚度明显高于OD组(P<0.05),且血管内膜炎性因子IL-1β和TNF-α蛋白表达具有同样的趋势。结论:以高脂饮食喂养健康兔子发现动脉粥样硬化模型兔子炎性因子IL-1β和TNF-α在血液中和血管内膜均有表达增高,或可与动脉粥样硬化相关。     

The effects of dexamethasone in vitro on the production of collagenase and inhibitor by synovial and cartilage explants from the joints of rabbits with a proliferative arthritis

Summary Using a rabbit model arthritis we have investigated the ability of dexamethasone to alter the production of collagenase and the specific metallo-proteinase inhibitor TIMP by explants of synovium and cartilage in vitro. The patterns of collagenase and TIMP production by untreated explants from arthritic joint tissues in culture were similar to those described previously [1, 2]. Dexamethasone dramatically altered the patterns of production of collagenase and TIMP. At a dose of 10 nM, or above, the patterns of production by treated synovium resembled those of normal rabbit synovium: collagenase production was suppressed and TIMP increased compared with untreated arthritic synovium. The levels of latent collagenase in cartilage also fell with increasing doses of dexamethasone and TIMP levels were higher, although normal levels were not reached.These experiments have been conducted as a prelude to testing the effects of various anti-rheumatic drugs in vivo, and attempting to correlate changes in clinical parameters with the subsequent production of collagenase and TIMP in vitro. The data are discussed in relation to the therapeutic use of corticosteroids and to their mode of action on joint tissues.     

CEUS观察兔肝VX2肿瘤坏死演变

目的应用CEUS技术观察兔肝VX2肿瘤坏死过程,探讨VX2肿瘤生长坏死规律及其对实验产生的影响。方法应用超声引导下经皮穿刺种植法成功建立24只兔VX2肝肿瘤模型,并通过CEUS技术分别在肿瘤种植后10、14、21、28天动态观察肝肿瘤演变过程,测量肿瘤体积及坏死体积,计算瘤内坏死率。结果在肿瘤种植后10、14、21、28天兔肝VX2肿瘤体积、坏死灶体积和坏死率比较,差异均有统计学意义(P均0.05);肿瘤种植后10、14、21、28天的CEUS表现能反映出肿瘤的病理学特征。实验依据CEUS和病理特点将肿瘤生长过程细分为5个时期,0~10天为肿瘤实质前期;11~14天为肿瘤实质后期;15~21天为肿瘤坏死初期;22~28天为加速坏死期;28天后为肿瘤囊变期。结论 CEUS可准确判断肝肿瘤实质及坏死范围;VX2肿瘤的生长演变及肿瘤坏死具有规律性,可根据不同实验要求选择适宜的研究时间段。     

建立家兔梗阻性无精症模型对显微外科培训的实验性探讨

目的 建立家兔梗阻性无精症的动物模型,为男科医生“显微输精管附睾管吻合术”技能的培养寻找一种可行的方法.方法 依据月龄、体重及精液分析结果,筛选出38只健康5～6月龄加利福尼亚雄性大白兔作为实验对象.对家兔实施“双侧输精管近睾端结扎术”,以建立家兔梗阻性无精症模型.2月后取精检查,无精子发现后,家兔行双侧“显微纵向两针叠套式输精管附睾管吻合术”.术后2～4月内,对每只雄兔每月连续采精3次,每次间隔3d,连取3月结束实验.运用SCA精液分析仪行精液分析,并记录主要精液参数;若未见精子,先对精液标本离心处理,在高倍镜下检查精子有无,记录最终结果.结果 (1)家兔梗阻性无精模型建立实验中,1例家兔因睾丸附睾坏死、伤口感染死亡;1只因麻药推注速度过快,心脏骤停,余36例梗阻模型的建立进行顺利,术后无发热,元腹泻等; (2)吻合部分,2只家兔因为单侧输精管近端回缩与睾丸鞘膜、精索粘连严重,而只行单侧吻合,余34只实验进行顺利; (3)术后4月内,行精液分析辅助离心后检测,其结果显示:共23只雄兔精液中检测到精子,4只在离心后高倍镜下仅检测到少数精子而无精液分析结果.另3例中途曾检测到精子,继续实验又未见精子.结论 显微输精管附睾管吻合动物实验具有具有微创、简易、安全的特点,可作为临床男科医生开展“显微镜输精管附睾管吻合术”前的一种良好技能训练平台.     

壮医通路酒皮肤毒性动物实验研究

目的：观察实验家兔皮肤接触壮医通路酒后的毒性反应。方法以实验家兔为试验动物,选取体重（2.5±0.25）kg的家兔按雌雄各半标准随机分组并造模,用壮医通路酒涂于创面,以米酒作对照,观察各组皮肤反应。结果与对照组比较,用药后实验用药各组家兔的正常皮肤和破损皮肤均无急性毒性、长期毒性及皮肤刺激反应,并且实验用药组与对照组对比无明显差异（ P＞0.05）。结论壮医通路酒皮肤局部用药治疗痹证有较好的安全性。     

Histomorphometric analysis of the temporal bone after change of direction of force vector of mandible: an experimental study in rabbits

Objectives

The present study aimed at performing a histological evaluation of the response of temporal bone tissue to a change of direction of the force vector of the mandible in relation to the base of the skull.

Material and methods

Adult rabbits were assigned into four groups with two control and four experimental animals in each group. Experimental animals underwent surgery, which resulted in a change of direction of the force vector on the right temporomandibular joint. Samples were collected after 15, 30, 60 and 90 days for histological analysis.

Results

In the two-way analysis of variance, the effect of group and time was statistically significant (p<0.001). Additionally, a statistically significant interaction between group and time was observed (p<0.001). Control animals showed normal growth and development of the temporal region. In the experimental group, the change in direction of the force vector of the mandible induced significant changes in the temporal bone, with a bone modeling process, which suggests growth of this cranial structure.

Conclusions

The methodology used in this experiment allows us to conclude that the change in direction of the force vector of the mandible in relation to the skull base induces remodeling and modeling processes in the temporal bone. The resumption of normal oral functions after bone healing of the mandibular fracture appears to increase cell activation in the remodeling and modeling of the temporal bone structure. The observation of areas of temporal bone modeling shows the relevance of further investigation on the correlation between the joint structures and craniofacial growth and development.     

Eritoran对蛛网膜下腔出血兔基底动脉IL-1β、TNF-α和IFN-β mRNA表达的影响

目的 探讨eritora对蛛网膜下腔出血(subarachnoid hemorrhage,SAH)兔基底动脉炎性细胞因子白细胞介素-1β(interleukin-1β,IL-1β)、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)和干扰素-β(interferon-β,IFN-β)mRNA表达的影响.方法 36只健康成年雄性新西兰兔随机分为SAH组(n=12)、生理盐水组(n=12)和eritoran组(n=12).采用枕大池自体动脉血二次注血法建立SAH模型,生理盐水组用生理盐水等量置换脑脊液,SAH组置换脑脊液后立即注入等量自体非肝素化动脉血,eritoran组在每次经枕大池注血后立即静脉注射eritoran( 1.5 mg/kg).进行摄食情况和神经功能缺损评分.实时荧光定量聚合酶链反应检测基底动脉IL-1β、TNF-α和IFN-β mRNA表达.结果 Eritoran组进食评分[(1.20 ±0.41)分对(2.20±0.61)分;t=53.073,P=0.002]、神经功能缺损评分[(1.46±0.32)分对(2.60±0.08)分;t=306.431,P=0.001]、IL-1β [(1.22±0.48)对(2.38±0.06);P=0.000]、TNF-α[(1.39±0.07)对(3.32±0.21),P=0.000]和IFN-β[(1.51±0.08)对(2.18±0.05),P=0.000] mRNA表达均显著低于SAH组.结论 Eritoran可下调SAH兔基底动脉炎性细胞因子IL-1β、TNF-α和IFN-β mRNA表达,增加摄食量,减轻神经功能缺损.