Customized 3D-printed occluders enabling the reproduction of consistent and stable heart failure in swine models

Reproducibility of clinical output is important when investigating therapeutic efficacy in pre-clinical animal studies.Due to its physiological relevance,a swine myocardial infarction(MI)model has been widely used to evaluate the effectiveness of stem cells or tissue-engineered constructs for ischemic heart diseases.Several methods are used to induce MI in the swine model.However,it is difficult,using these approaches,to obtain a similar level of functional outcomes from a group of animals due to interpersonal variation,leading to increased experimental cost.Hence,in order to minimize human intervention,we developed an approach to use a customized occluder that has dimensional similarities with that of the coronary artery of animals in the case of the swine model.We carried out angiography to measure the diameter of the middle left anterior descending artery of each individual animal to fabricate the customized occluder using a 3D-printing system.The fabricated occluder contained a central hole smaller than that of the targeted middle left anterior descending artery to mimic an atherosclerotic coronary artery that has an approximately 20%blocked condition.Interestingly,the 3D-printed occluder can provide continuous blood flow through the central pore,indicating a high survival rate(88%)of up to 28 days post-operation.This method showed the possibility of creating consistent myocardial infarction induction as compared to the conventional representative closed-chest method(50%survival rate),thus highlighting how our method can have a profound effect on accelerating reliable experiments for developing new therapeutic approaches to ischemic heart diseases.

Swine model in transplant research: Review of anaesthesia and perioperative management

Pigs are one of most common animal species to be used in biomedical models due to their many anatomical visceral similarities with humans, particularly with regards to transplantation. Despite this use, in many of the researches in which pigs are selected for transplantation, the anaesthesia used is an adaptation of human anaes-thesia and presents some limitations such as a reduced analgesia a limited control in perioperative period. In this review we show some of the most important conditions in the preanaesthetic management and of swine as well as we review of anaesthetic protocols for the most common types of swine model of transplantation.

Effect of SAM junctional tourniquet on respiration when applied in the axilla: A swine model

Purpose:SAM junctional tourniquet(SJT)has been applied to control junctional hemorrhage.However,there is limited information about its safety and efficacy when applied in the axilla.This study aims to investigate the effect of SJT on respiration when used in the axilla in a swine model.Methods:Eighteen male Yorkshire swines,aged 6-month-old and weighing 55-72 kg,were randomized into 3 groups,with 6 in each.An axillary hemorrhage model was established by cutting a 2 mm transverse incision in the axillary artery.Hemorrhagic shock was induced by exsanguinating through the left carotid artery to achieve a controlled volume reduction of 30% of total blood volume.Vascular blocking bands were used to temporarily control axillary hemorrhage before SJT was applied.In Group I,the swine spontaneously breathed,while SJT was applied for 2 h with a pressure of 210 mmHg.In Group II,the swine were mechanically ventilated,and SJT was applied for the same duration and pressure as Group I.In Group III,the swine spontaneously breathed,but the axillary hemorrhage was controlled using vascular blocking bands without SJT compression.The amount of free blood loss was calculated in the axillary wound during the 2 h of hemostasis by SJT application or vascular blocking bands.After then,a temporary vascular shunt was performed in the 3 groups to achieve resuscitation.Pathophysiologic state of each swine was monitored for 1 h with an infusion of 400 mL of autologous whole blood and 500 mL of lactated ringer solution.Tb and T0 represent the time points before and immediate after the 30% volume-controlled hemorrhagic shock,respectively.T30,T60,T90 and T120,denote 30,60,90,and 120 min after T0(hemostasis period),while T150,and T180 denote 150 and 180 min after T0(resuscitation period).The mean arterial pressure and heart rate were monitored through the right carotid artery catheter.Blood samples were collected at each time point for the analysis of blood gas,complete cell count,serum chemistry,standard coagulation tests,etc.,and thromboelastography was conducted subsequently.Movement of the left hemidiaphragm was measured by ultrasonography at Tb and T0 to assess respiration.Data were presented as mean±standard deviation and analyzed using repeated measures of two-way analysis of variance with pairwise comparisons adjusted using the Bonferroni method.All statistical analyses were processed using GraphPad Prism software.Results:Compared to Tb,a statistically significant increase in the left hemidiaphragm movement at T0 was observed in Groups I and II(bothp<0.001).In Group III,the left hemidiaphragm movement remained unchanged(p=0.660).Compared to Group I,mechanical ventilation in Group II significantly alleviated the effect of SJT application on the left hemidiaphragm movement(p<0.001).Blood pressure and heart rate rapidly increased at T0 in all three groups.Respiratory arrest suddenly occurred in Group I after T120,which required immediate manual respiratory assistance.PaO_(2) in Group I decreased significantly at T120,accompanied by an increase in PaCO_(2)(both p<0.001vs.Groups II and III).Other biochemical metabolic changes were similar among groups.However,in all 3 groups,lactate and potassium increased immediately after 1 min of resuscitation concurrent with a drop in pH.The swine in Group I exhibited the most severe hyperkalemia and metabolic acidosis.The coagulation function test did not show statistically significant differences among three groups at any time point.However,D-dimer levels showed a more than 16-fold increase from T120 to T180 in all groups.Conclusion:In the swine model,SJT is effective in controlling axillary hemorrhage during both spontaneous breathing and mechanical ventilation.Mechanical ventilation is found to alleviate the restrictive effect of SJT on thoracic movement without affecting hemostatic efficiency.Therefore,mechanical ventilation could be necessary before SJT removal.

基于模式病毒评价商品化消毒剂对非洲猪瘟病毒的消杀效果

为了解常用商品化消毒剂对非洲猪瘟病毒(ASFV)的消杀效果,为其消毒剂的筛选提供参考。该研究利用伪狂犬病毒(pseudorabies virus,PRV)与ASFV病毒理化特征的相似性,以PRV作为替代标识毒株,建立了消毒剂细胞评价模型,于体外检测了3种市售消毒剂对生长在BHK-21细胞中PRV的灭活效果。分别从3类消毒剂的不同方面对消毒剂抗病毒作用的影响进行消杀效果的评估。研究显示,有效含量为0.125 g·L^(-1)的戊二醛癸甲溴铵溶液,以及有效含量为0.5 g·L^(-1)的过氧乙酸溶液和二氯异氰脲酸钠,在室温作用30 min,均可有效灭活PRV。其中,过氧乙酸综合评价最优;戊二醛癸甲溴铵性价比最高,但所需消杀时间较长,受低温影响比较严重。该研究可为养殖场防控ASFV的感染提供消毒剂筛选的理论依据,并对ASFV的消毒标准提供参考。

猪流行性腹泻病毒PEDV SD株的分离及体外3D肠道类器官感染模型建立

猪流行性腹泻病毒(PEDV)是一种主要感染仔猪小肠的肠道冠状病毒。本研究旨在建立一种用于PEDV体外研究的仔猪小肠类器官模型。首先从PEDV发病猪场的临床仔猪腹泻样品中分离PEDV并进行全基因组测序,结果显示成功分离1株PEDV,命名为PEDV SD株。另外采用肠道类器官的培养技术,从10日龄健康仔猪小肠中分离小肠隐窝组织,经过体外培养7 d左右分化成具有肠道隐窝结构的猪小肠类器官,并能进行连续传代。然后将分离的PEDV SD株感染传代培养的猪小肠道类器官,通过间接免疫荧光试验显示PEDV可以很好地感染猪小肠道类器官,表明成功建立了PEDV感染肠道类器官的模型。猪小肠类器官感染模型可以在体外很好地重现PEDV感染肠道细胞的复杂结构的过程,为深入研究PEDV的致病机制提供一种新的可再生的体外研究模型。

H5N1亚型猪流感病毒A／Swine／Fujian／1／01感染性克隆构建及其对小鼠致病性研究

2001年从福建某猪场分离到1株H5N1亚型猪流感病毒(SIV)A/Swine/Fujian/1/01(SW/FJ/1/01)。SW/FJ/1/01对小鼠具有强致病性,致死率为100%,为进一步研究SW/FJ/1/01对BALB/c小鼠致病性的分子基础,本研究构建了SW/FJ/1/01的8个节段重组质粒构成的反向基因操作系统,成功拯救了病毒(R-SW/FJ/1/01)。R-SW/FJ/1/01和野生型SW/FJ/1/01对BALB/c小鼠致病性没有差别。SW/FJ/1/01反向基因操作系统的建立为进一步阐明H5N1亚型SIV对哺乳动物模型BALB/c小鼠的致病机制等方面的研究奠定了基础。

Price Transmission in China's Swine Industry with an Application of MCM

The paper studies the relationship, adjustment ability, path, efficiency and intensity of price transmission in the swine industry chain in China, which consists of the prices of corn, compound feed for fattening pig, piglet, pig and pork. Monthly prices covering a period of 18 yr （1994-2011） are analyzed using a Market-Chain Cooperated Model （MCM）. The empirical results show that there exists a stable long-term cointegration and short-term dynamic relationship in the price system. First, the adjustment speed of each price series is very slow and the transmission path is top-down and one-way significantly. Second, the price from upstream to downstream lags about 2 mort, while there is no lag in price transmission from midstream to downstream. Third, in terms of price transmission intensity, the price of pig impacted greatly on pork price, not only in the current period but also through the whole period. Besides, the price of corn has the largest lagged effects on pork price. According to the above empirical results, we suggest that government should strengthen monitoring and early warning of the swine industry chain, especially the upstream and midstream, attach great importance to the timely adjustment of feed prices and perfect the measures of price subsidy.

生猪产业规模化发展与碳排放:促进还是抑制?

在使用生命周期法测算2007−2020年省际生猪碳排放的基础上,系统考察了生猪产业规模化发展对生猪碳排放的影响与作用机制。结果表明:第一,生猪碳排放呈现出明显的空间溢出效应和聚集效应,即一个地区的生猪碳排放与周边地区密切相关;第二,生猪产业规模化发展对生猪碳排放呈现显著的“倒U型”关系,规模化发展对生猪碳排放的影响存在显著的门槛效应,当生猪产业规模化率保持在45.1%以上时,规模化发展可有效促进生猪产业碳减排;第三,小规模生猪养殖占比与生猪碳排放是显著的单调递增关系,而中规模和大规模生猪养殖占比与生猪碳排放之间表现显著的“倒U”型关系;第四,聚集效应和技术进步效应是生猪产业规模化发展影响生猪碳排放的主要作用途径。建议合理规划生猪产业的空间布局,发展适度规模养殖,发挥技术进步的推动作用,稳妥实现生猪产业碳减排与规模化发展的“双赢”目标。

不同缺血时间对中国小型猪心肌缺血再灌注损伤的影响研究

目的探讨不同缺血时间对中国小型猪急性心肌缺血再灌注损伤的影响,为建立适合的小型猪心肌缺血再灌注模型提供依据。方法中国小型猪29只,随机分为假手术组(6只)、缺血30 min组(7只)、缺血60 min组(7只)及缺血90 min组(9只)。各组戊巴比妥钠麻醉后行左冠状动脉造影,后将球囊经导丝交换入冠脉左前降支中部,术中连续心电监护记录ST段改变情况、室颤及除颤次数,再灌注3 h后处死。于缺血前、再灌即刻、再灌后1 h、2 h及3 h采集超声心动图,描记心脏收缩功能左心室射血分数(left ventricular ejection fraction,EF)及左心室短轴缩短率(left ventricular fractional shortening,FS);检测血清肌酸激酶同工酶(creatine kinase isoenzyme,CKMB)、乳酸脱氢酶(lactate dehydrogenase,LDH)及超氧化物歧化酶(superoxide dismutase,SOD)活性,丙二醛(malondialdehyde,MDA)含量。TTC/伊文思蓝双重染色观察心肌梗死面积,硫磺素S染色法观察再灌后无复流面积。结果缺血90 min组动物死亡率较缺血30 min组、缺血60 min组高;随缺血时间增长,室颤及除颤次数明显增加(P<0.05,P<0.01);缺血90 min组再灌注3 h时EF值、FS值较其他组明显降低(P<0.05,P<0.01);模型组动物在心电图缺血性改变、心肌梗死及无复流面积、心肌组织染色及血清CK-MB、LDH、SOD、MDA含量方面无显著性差异。结论心肌缺血90 min再灌注小型猪模型的恶性心律失常及死亡率高,缺血30 min再灌注3 h条件建立的模型能复制临床疾病的特征性病变且死亡率低,适合于发病机制及药物作用研究。

A novel access method for endovascular procedures in the porcine model

Objective To evaluate the use of the saphenous artery as an alternative access for endovascular procedures in the porcine model. Methods Fourteen adult pigs (25-35 kg) were used in this study, 3 pigs from an acute study and 11 from chronic studies. A 2-3 cm incision was made and a saphenous artery cutdown was performed in 24 sides. Micropuncture sets (Boston Scientific) or 18 G puncture needles were used to access the artery. Different sizes of introducers (4-7 F) were used to establish endovascular access. Angiographic catheters were then used to confirm if the access was usable. Four saphenous arteries were explanted in the pigs from a chronic study 4 to 28 days after surgical procedure. Results The saphenous artery was very easy to expose and 4-5 F introducer sheaths were able to be inserted to establish access for endovascular procedures in the pigs. The saphenous artery was unable to accomodate an introducer with a size larger than 6 F. Four saphenous arteries were injured when 5 and 6 F introducers were used, but angiographic procedures could still be performed. Morphologic evaluation of the explanted arteries demonstrated occlusion of the saphenous arteries without injury or disruption of the adjacent femoral arteries. Conclusion The saphenous artery can be used as an access site in pigs for angiographic and interventional procedures if the catheter size is less than 6 F. This vessel is easier to access and can preserve the femoral artery for repeat procedures in the future.

小香猪DCD边缘供体模型的构建及其供肾病理学观察

目的建立一种小香猪心脏死亡后器官捐献(donation after cardiac death,DCD)供体模型,并对DCD供肾进行病理学评价。方法7只4~6月龄的雄性小香猪(13~17 kg)分为标准供体对照组(C组,n=3)和DCD组(n=4),两组肌注苯巴比妥钠麻醉诱导后,建立耳缘静脉通道,行血压、心电图和氧饱和度(SaO_(2))监测,同时注射丙泊酚、舒芬太尼强化麻醉诱导效果。C组气管插管后机械通气,丙泊酚、瑞芬太尼和顺阿曲库铵维持麻醉,行开腹术摘取肾脏;DCD组静脉推注肝素(300 IU/kg)抗凝,后注射丙泊酚600 mg和顺阿曲库铵10 mg使猪心跳呼吸停止,待心停跳30 min时摘取肾脏。2组肾脏均切成小块组织,4%多聚甲醛固定,行石蜡包埋,采用HE染色,光镜下观察正常肾脏和DCD边缘供体肾脏的病理结果变化并进行组织损伤评分。结果DCD组共成功建模4只猪在注射过量麻醉药后SaO_(2)下降至80%的平均时间为(3.25±1.89)min,心脏骤停平均时间为(7.75±3.10)min;热缺血30 min后获取的DCD边缘供肾与C组供肾相比,肾小管损伤评分增高(P<0.05),肾小球损伤评分均值增高,但差异无统计学意义。结论采用静脉注射过量丙泊酚和顺阿曲库铵的方法可有效建立猪DCD边缘供体模型。

突发性动物疫情事件对生猪价格的冲击效应分析——以非洲猪瘟事件为例

在我国,生猪价格的走向引发着社会各界的持续关注。一方面猪肉是我国居民生活消费的必需品,另一方面猪肉价格的波动对中国居民消费价格指数和物价水平有着尤为显著的影响。近年来,我国突发性动物疫情事件频发,尤其是非洲猪瘟疫情的产生,使得生猪价格异化更为严重,波动更加频繁。文章以2015年1月-2018年7月我国生猪月平均价格为建模基础,借助ARIMA时间序列模型深入剖析突发性动物疫情事件对生猪市场价格的冲击作用,并为其提供科学的量化结果。研究显示:突发性动物疫情事件一般是通过降低生产者饲养能力与打击消费者购买信心等渠道影响供需,进而对生猪价格产生强烈冲击,并且这种冲击效应存在时滞性与阶段性特征。

Nakagami-Gamma统计模型参数成像表征高强度聚焦超声致热损伤:体外研究

目的观察基于Nakagami-Gamma统计模型参数成像表征高强度聚焦超声(HIFU)致热损伤的效果。方法对离体猪里脊组织行HIFU热消融,于辐照间隙采集超声射频数据,以Nakagami-Gamma统计模型估计β参数并形成参数图,计算其与参考帧的对数差分;同步构建传统灰阶声像图和灰阶超声差分图,与Nakagami-Gamma对数差分图对比,根据热损伤区与周围组织的对比度噪声比(CNR)评价模型性能。结果利用Nakagami-Gamma模型可在灰阶声像图无明显相应表现时监测热损伤,且能明显提高消融区对比度。Nakagami-Gamma对数差分图的CNR[(1.04±0.60)dB]明显高于灰阶超声差分图[(0.35±0.18)dB](t=18.189,P<0.001),整体相对提升49.64%。结论Nakagami-Gamma统计模型可用于表征HIFU致热损伤。

经胸腔镜建立巴马小型猪冠状动脉狭窄模型

目的探讨一种高效、稳定的经胸腔镜构建不同程度冠状动脉狭窄动物模型的方法。方法 20头巴马小型猪,在胸腔镜直视下手术丝线永久性环扎左前降支近端,从而造成前降支不同程度的狭窄。术后进行定量冠状动脉造影检查评价狭窄程度。结果 20头小型猪中18头手术顺利完成,2头术中出现室颤,除颤成功后分别于术后8 h和48 h死亡。术后行定量冠状动脉造影显示7头小型猪狭窄程度不超过50%,6头狭窄程度在50%到70%,5头狭窄程度在70%以上,即时手术成功率100%,建模成功率90%。结论完全胸腔镜下应用丝线环扎法可成功地制作不同程度的冠脉狭窄动物模型。

猪气喘病实验猪模型的建立

目的研究建立猪气喘病人工发病模型。方法将分离得到的一株猪肺炎支原体(Mycoplasma hyopneumoniae,Mhp)Js株进行各种试验鉴定,证实其为Mhp强毒株。每头猪肺内接种Js株培养物2ml,15～25d后观察临床症状和病理变化,采集病变组织,经冻干制成攻毒用组织毒。安检合格,批号为20000324。给15头小梅山二元杂交猪分别气管内注射以KM_2培养基作10^(-2)、10^(-3)、10^(-4)和10^(-5)稀释的强毒,每头猪5ml,对照组注射培养基。攻毒后25d观察试验猪临诊症状,X线透视,记录病理变化。结果10^(-2)、10^(-3)、10^(-4)稀释的强毒试验组猪均出现了典型的猪气喘病临床症状和病理变化。结论人工发病试验测得Mhp Js株组织强毒接种气管内注射最小发病剂量为10^(-4)稀释5ml,正式试验人工发病可用100个最小发病剂量即强毒冻干物1:100稀释气管内注射5ml,可确保攻毒成功。

介入法建立猪急性心肌梗死再灌注模型及其效果评价

目的:用介入法行球囊堵闭猪冠状动脉左前降支(LAD)建立急性心肌梗死再灌注动物模型并评价其效果。方法:选用小型雄性家猪11只。麻醉后经股动脉或颈总动脉置入经皮腔内冠状动脉成形术(PTCA)球囊至冠状动脉LAD远端,堵闭血流60 min。术中持续静脉滴注胺碘酮。60min后负压撤除球囊及鞘管。行超声心动图、磁共振成像(MRI)评价心肌梗死模型建立情况,并行病理分析。结果:2只猪死于心肌梗死模型制备,存活的9只猪经超声心动图、MRI检测显示梗死部位均为左心室前壁、心尖区,部分模型累及室间隔,左室下壁,并有室壁瘤、室速等心肌梗死常见并发症的发生。结论:运用介入法经PTCA球囊LAD可成功建立猪急性心肌梗死模型。这种模型重复性强,可控性好,模型的梗死部位基本一致,易于术后评价。

经皮冠脉内球囊封堵建立猪心梗模型

目的探讨经皮冠状动脉内球囊封堵建立猪急性心肌梗死模型的方法。方法健康猪11只，4-5月龄，体重25～40kg。其中7例球囊置于第三间隔支动脉分出处，4例置于第二间隔支动脉分出处。试验前每只动物均进行缺血预适应，阻断前向血流1min、2min、5min，每次间隔60s，然后持续阻断前向血流60min。球囊扩张压力为2atm。观察心电图、心脏二维超声及冠状动脉和左心室造影。结果成功建立猪心肌梗死模型9例，2只因术中顽固性室颤死亡，死亡者一例为左前降支中段阻断，心电图及活检证实为广泛前壁心梗。共有7例发生室颤，其余5例均抢救成功。心电图显示急性心肌梗死典型图形变化，术后1h超声检查出现梗塞部位局部运动异常，心脏MRI检查出现梗塞部位首过灌注缺损，延迟强化。结论经皮腔内球囊封堵冠状动脉可成功建立猪急性心肌梗死模型，具有创伤小、动物生存时间长并易于术后饲养等优点。

介入法建立比格犬和小型猪急性心肌梗死模型的对比研究

目的比较介入法建立比格犬与小型猪两组动物急性心肌梗死模型的成功率及风险,为选择更合适的动物建模提供理论基础。方法比格犬和五指山小型猪各6头,全身麻醉下行右侧股动脉切开穿刺术,左冠状动脉造影后选择冠状动脉球囊送至前降支中段行缺血预适应,并持续封堵180min后撤出球囊,术前、术后均连续观察心电图变化,术后7d处死动物取出心脏行病理学检查。结果比格犬组均存活,小型猪组死亡1例(1/6);比格犬组发生心肌梗死1例(1/6),小型猪组5例(5/6);比格犬组未发生恶性心律失常,小型猪组6例均发生恶性心律失常(6/6);两组造模所需时间比较[(4.61±0.47)h vs.(4.82±0.55)h],差异无统计学意义(P>0.05)。结论小型猪在介入法建立心肌梗死模型中虽然风险高于比格犬,但是成功率仍较高,是建模的理想动物。

中国小型猪阻塞型睡眠呼吸暂停模型的建立

目的 建立一个稳定、可靠、与临床病理状态接近的阻塞型睡眠呼吸暂停 (OSA)动物模型。方法 中国小型猪 10头 ,分为A、B两组 ,A组采用凝胶外部注射法制作模型 ;B组采用凝胶内部注射法制作模型。手术过程中及结束后 ,用多导睡眠仪检测脑电图、口鼻气流、鼾声、胸式呼吸、腹式呼吸、血氧饱和度。 1周后复查多导睡眠图。 2周后行CT检查 ,3个月后处死动物行病理形态学检查。结果 手术结束后两组动物均出现呼吸暂停或低通气及血氧饱和度下降 ,组间相比呼吸暂停时间、呼吸暂停指数、血氧饱和度无明显差别。 1周后复查 ,两组呼吸暂停时间、呼吸暂停指数均较术后当天明显增加 ,血氧饱和度明显下降 ,P <0 0 5 ,B组上述指标的变化更为明显 ,P <0 0 5。CT检查结果 :A组咽腔有一定程度的狭窄 ;B组咽腔呈明显狭窄状。病理形态学结果 :光镜下可见呈交联状的凝胶 ,表面有一层由排列整齐的胶原纤维和弹性纤维形成的结缔组织薄膜 ,胶原纤维和弹性纤维向凝胶内部生长。结论 凝胶注射法建立的慢性阻塞型睡眠呼吸暂停模型稳定、可靠、重复性好 ,与临床病理状态接近 ,可进行长期的、动态的研究 ,可广泛应用于睡眠呼吸暂停综合征发病机制、病理生理及治疗学等领域的研究 ,相比而言 ,内部注射法更优。

西藏猪模型对新型生物人工肝治疗安全性的评估

目的评估新型生物人工肝大动物实验的安全性。方法将6只西藏猪采用混合与单纯两种生物治疗模式,观察记录实验过程中每小时生命体征、静脉压、跨膜压、入浆壶压的变化,并在实验开始时及实验4、8h抽取静脉端血做内毒素及血培养检测。结果生物人工肝机器的静脉压、跨膜压、入浆壶压值在实验5h较实验开始时明显增高(P<0.05),而其余各时间点与实验开始时比较差异无统计学意义(P>0.05)。各时间点平均动脉压、呼吸频率比较差异无统计学意义(P>0.05),实验2h心率与实验开始时比较差异有统计学意义(P<0.01),实验开始时及实验4、8h抽血所测得的内毒素结果均小于0.5EU/mL,血培养结果显示培养15d未见细菌生长。结论新一代生物人工肝大动物实验安全,可以进一步评价猪的肝衰竭模型的有效性。