弹力酶诱导兔动脉瘤模型修复过程初步研究

目的:观察猪胰弹性酶快速诱导建立兔囊状动脉瘤模型的形态学改变和早期病理学变化,探讨动脉瘤的创伤修复机制,为动脉瘤的治疗寻找新的切入点。方法:应用猪胰弹性酶消化兔右侧颈总动脉起始部建立动脉瘤模型,3 d、7 d、21 d灌注取出动脉瘤组织,采用病理学、免疫组织化学、脑血管造影技术研究该模型的影像学和病理学变化。结果:病理学观察发现动脉瘤顶部均有红血栓形成,血管内皮细胞消失,瘤壁完全缺失弹力层,载瘤动脉的弹力层在动脉瘤颈部突然消失,动脉瘤内膜逐渐增生,但仍缺乏弹力层,平滑肌细胞和胶原纤维增生明显。免疫组织化学均显示内膜VonWillebrand因子(vWF)染色阴性。对照组动物均形成动脉残端,动脉残腔内无或少量血栓,血管壁结构完整。造影显示21 d动脉瘤长径(6.40±1.62)mm,宽径(4.41±1.15)mm,瘤颈宽(5.30±2.51)mm,载瘤动脉直径(3.99±1.59)mm。结论:通过简单外科手术方法结合弹力酶消化局部血管壁,可以建立病理学和形态学上与人颅内动脉瘤相似的动脉瘤模型。动脉瘤模型早期存在一定的自身修复机制,内膜逐渐增生,以平滑肌细胞和胶原纤维增生为主,未见弹力纤维和内皮细胞增生修复。     

Invasive rabbits host immature Ixodes ticks at the urban-forest interface

Introduced wildlife may be important alternative hosts for generalist ticks that cause health issues for humans and companion animals in urban areas, but to date are rarely considered as part of the tick-host community compared to native wildlife. In Australia, European rabbits, Oryctolagus cuniculus, are a widespread and abundant invasive species common to a range of human-modified ecosystems. To understand the potential role of rabbits in the life cycle of Australian ticks, we investigated the seasonal abundance of all tick life stages (larva, nymph, and adult) on rabbits collected from pest control programs in two urban forest remnants in Sydney, Australia. We also recorded whether larvae, nymphs, and adults were attached to the head, body, or limbs of rabbits to reveal patterns of tick attachment. Of the 2426 Ixodes ticks collected from 42 rabbits, larvae were by far the most abundant life stage (2360), peaking in abundance in autumn, while small numbers of nymphs (62) and adults (4) were present in winter and summer respectively. Larvae were found all over the body, whereas adults and nymphs were predominantly attached to the head, suggesting that the mature life stages use the host landscape differently, or that adults or nymphs may be groomed off the body. The most abundant tick species, as determined by morphology and DNA sequencing, was Ixodes holocyclus, a generalist tick responsible for significant human and companion animal health concerns in Australia. Our findings highlight the importance of understanding the role of introduced wildlife in tick dynamics particularly in novel ecosystems where non-native hosts may be more abundant than native hosts.     

Gelfoam haemostatic agent with or without autologous bone marrow-derived stem cells for the regeneration of critical-size mandibular defects in the rabbit

This study evaluated the effect of Gelfoam sponge with and without autologous bone marrow-derived stem cells (BMSCs) on bone regeneration in critical-size mandibular defects. The study involved 56 New Zealand rabbits assigned to four groups (14 in each). The osseous defects in group I were irrigated with normal saline, those in group II were grafted with autogenous tibial bone, and those in group III were filled with Gelfoam sponge. Group IV defects were treated as for group III, but the interface between the Gelfoam sponge and bone surface was injected with BMSCs. At the end of 4 weeks, seven rabbits in each group were euthanized; the remaining animals were euthanized at the end of the experiment, at 8 weeks postoperative. The percentage area of newly formed bone was significantly higher in group IV at week 4 (0.030 ± 0.01%) and week 8 (0.060 ± 0.03%) than in group I (0.01 ± 0.00% and 0.02 ± 0.00%, respectively) and group III (0.08 ± 0.01% and 0.015 ± 0.02%, respectively), but was lower than that in group II (0.038 ± 0.02% and 0.082 ± 0.01%, respectively). Thus, the combination of Gelfoam and autologous BMSCs promoted the regeneration of mandibular critical-size defects better than the use of Gelfoam alone. However, the amount of newly generated bone was lower than in defects grafted with autogenous bone.     

针刀松解联合丹参注射液关节腔注射治疗骨性关节炎模型兔

文题释义： 针刀疗法：用一个完整的语言来概括应该是一种介于手术方法和非手术疗法之间的闭合性松解术。针刀疗法是将东方中医学的基本理论和西方医学的手术解剖基本理论融为一体，针刀疗法其操作的特点是在治疗部位刺入深部到病变处进行轻松的切割、剥离等不同的刺激，以达到止痛祛病的目的。 丹参注射液：其化学成分主要是水溶性酚酸类化合物，通过多种靶标起到促进血液循环和祛瘀的作用。动物研究表明，丹参注射液可通过抑制IκBα磷酸化来抑制NF-κB信号通路的激活。保护软骨下骨及软骨细胞，有效防治骨关节炎。 背景：丹参注射液与针刀松解术都是临床中治疗骨关节炎很常用的技术，目前缺乏对2种治疗方法联合使用的研究。 目的：对比单独使用针刀松解术、单独使用丹参注射液与两种方法联合使用治疗兔模型骨关节炎的效果。 方法：实验方案经黑龙江中医药大学动物实验伦理委员会批准。50只新西兰白兔分为5组：空白对照组；模型组；丹参注射液组；针刀组；针刀联合丹参注射液组。除空白对照组外，其他4组兔均制备膝关节骨关节炎模型。造模成功后，对针刀组兔内外侧支持带、内外侧膝眼，膝关节上方髌上囊、股四头肌各肌肌腹，膝关节内侧股薄肌肌腹及止点、收肌肌群肌腹及止点和胫骨平台附近部位进行针刀松解；空白对照组及模型组兔关节腔注射生理盐水0.3 mL；丹参注射液组兔关节腔每次注射0.3 mL丹参注射液；针刀联合丹参注射液组：每周进行1次针刀治疗同针刀组，每次针刀干预之后，关节腔注0.3 mL丹参注射液。上述干预每周1次，持续5周。对各组兔膝关节软骨进行大体观察及病理切片组织学观察，ELISA 检测关节液白细胞介素1、肿瘤坏死因子α水平。 结果与结论：①大体观察：模型组膝关节磨损较为严重，针刀组、丹参注射液组、针刀联合丹参注射液组膝关节轻度磨损；②病理切片评分：丹参注射液组评分略高于针刀组和针刀联合丹参注射液组差异无显著性意义；③ELISA 检测结果：针刀联合丹参注射液组白细胞介素1、肿瘤坏死因子α水平显著低于或针刀组或丹参注射液组(P < 0.05)；④结果说明，在兔膝关节骨关节炎模型中降低白细胞介素1、肿瘤坏死因子α水平方面，针刀松解术结合丹参注射液关节腔注射治优于单独使用针刀或单独使用丹参注射液关节腔注射。ORCID: 0000-0003-4119-633X(刘广宇) 中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程     

Study on prevalence and genotype of hepatitis E virus isolated from Rex Rabbits in Beijing,China

Summary. A novel genotype of hepatitis E virus (HEV) isolated from rabbits is reported. The aim of this study was to confirm and further investigate the prevalence of the novel HEV genotype in rabbits in China. Sera and faecal samples were collected from farmed rex rabbits in Beijing, China. All serum samples were tested for anti‐HEV antibody by EIA. Both the serum and the faecal samples were evaluated for detection of HEV RNA using a nested RT‐PCR assay. The nucleotide sequences of rabbit HEV were then analysed, and sequence homology of rabbit HEV compared against human HEV genotypes 1–4, and avian HEV. Results: The prevalence of positive serum anti‐HEV from rex rabbits was 54.62% (65/119). The detection rate of HEV RNA using ORF2 primers was 6.96% (8/115) amongst rabbit faecal samples. All eight amplicons shared 98.3–100% nucleotide homology with each other and had identities of 75.8–78.6%, 73.9–75.0%, 77.5–81.0%, 74.2–78.6% and 54.8–57.6% with the corresponding regions of genotypes 1–4 and avian HEV, respectively. Phylogenetic analysis showed that the eight sequences formed one individual branch and were on the same branch with GDC9 and GDC46, both of which were reported to be a novel genotype of HEV isolated from rabbits. The conclusion is that this study provides further information about HEV infecting rabbits, which may be a new animal host of HEV, as well as genetical evidence of a new mammalian genotype of HEV.     

Difference in the Burst Patterns of Digastric and Mylohyoid Activities during Feeding in the Freely Behaving Rabbit

Burst patterns in the digastric, mylohyoid, and masseter muscles and the resultant jaw movement orbits during chewing and swallowing were investigated in the freely behaving rabbit. Activities in the posterior mylohyoid fibers consisted of two continuous bursts. Peaks in the first burst of the posterior fibers occurred in the middle part of opening and preceded the digastric burst. Peaks in the second burst occurred in the final part of opening and coincided with those in the working side of the digastric burst. After removal of the bilateral digastric muscles, the gape size during chewing was largely reduced in the final part of opening and in the early part of closing. The results suggest that (a) the digastric may have a role in opening the mandible widely beyond the rest position but may not have a major role in the control of the horizontal (mediolateral) jaw movement, (b) the posterior mylohyoid fibers may have a function as an elevator of the tongue in the early part of opening, and (c) the posterior mylohyoid fibers may have a function as a depressor of the jaw in the late part of opening. Electromyographic burst in the mylohyoid muscle began with marked activity in the mid-closing phase. The results support a role for the mylohyoid muscle as a leading muscle of swallowing. Swallowing events in the rabbit are easily distinguished from the activities of the mylohyoid muscle and the thyrohyoid muscle.     

Dual‐Dye Optical Mapping after Myocardial Infarction: Does the Site of Ventricular Stimulation Alter the Properties of Electrical Propagation?

Introduction: Myocardial infarction (MI) disrupts electrical conduction in affected ventricular areas. We investigated the effect of MI on the regional voltage and calcium (Ca) signals and their propagation properties, with special attention to the effect of the site of ventricular pacing on these properties.
Methods: New Zealand White rabbits were divided into four study groups: sham-operated (C, n = 6), MI with no pacing (MI, n = 7), MI with right ventricular pacing (MI + RV, n = 6), and MI with BIV pacing (MI + BIV, n = 7). At 4 weeks, hearts were excised, perfused, and optically mapped. As previously shown, systolic and diastolic dilation of the LV were prevented by BIV pacing, as was the reduction in LV fractional shortening.
Results: Four weeks after MI, optical mapping revealed markedly reduced action potential amplitudes and conduction velocities (CV) in MI zones, and these increased gradually in the border zone and normal myocardial areas. Also, Ca transients were absent in the infarcted areas and increased gradually 3–5 mm from the border of the normal zone. Neither BIV nor RV pacing affected these findings in any of the MI, border, or normal zones.
Conclusions: MI has profound effects on the regional electrical and Ca signals and on their propagation properties in this rabbit model. The absence of differences in these parameters by study group suggests that altering the properties of myocardial electrical conduction and Ca signaling are unlikely mechanisms by which BIV pacing confers its benefits. Further studies into the regional, cellular, and molecular benefits of BIV pacing are therefore warranted.     

Effects of neferine on Kv4.3 channels expressed in HEK293 cells and ex vivo electrophysiology of rabbit hearts

Aim:

Neferine is an isoquinoline alkaloid isolated from seed embryos of Nelumbo nucifera (Gaertn), which has a variety of biological activities. In this study we examined the effects of neferine on Kv4.3 channels, a major contributor to the transient outward current (I_to) in rabbit heart, and on ex vivo electrophysiology of rabbit hearts.

Methods:

Whole-cell Kv4.3 currents were recorded in HEK293 cells expressing human cardiac Kv4.3 channels using patch-clamp technique. Arterially perfused wedges of rabbit left ventricles (LV) were prepared, and transmembrane action potentials were simultaneously recorded from epicardial (Epi) and endocardial (Endo) sites with floating microelectrodes together with transmural electrocardiography (ECG).

Results:

Neferine (0.1–100 μmol/L) dose-dependently and reversibly inhibited Kv4.3 currents (the IC₅₀ value was 8.437 μmol/L, and the maximal inhibition at 100 μmol/L was 44.12%). Neferine (10 μmol/L) caused a positive shift of the steady-state activation curve of Kv4.3 currents, and a negative shift of the steady-state inactivation curve. Furthermore, neferine (10 μmol/L) accelerated the inactivation but not the activation of Kv4.3 currents, and markedly slowed the recovery of Kv4.3 currents from inactivation. Neferine-induced blocking of Kv4.3 currents was frequency-dependent. In arterially perfused wedges of rabbit LV, neferine (1, 3, and 10 μmol/L) dose-dependently prolonged the QT intervals and action potential durations (APD) at both Epi and Endo sites, and caused dramatic increase of APD₁₀ at Epi sites.

Conclusion:

Neferine inhibits Kv4.3 channels likely by blocking the open state and inactivating state channels, which contributes to neferine-induced dramatic increase of APD₁₀ at Epi sites of rabbit heart.     

Antioxidant effects and anti-elastase activity of the calcium antagonist nicardipine on activated human and rabbit neutrophils--a potential antiatherosclerotic property of calcium antagonists?

Activated neutrophils which produce certain proteases, such as elastase and reactive oxygen species (ROS) are involved in oxidative stress and inflammation. In the present study, we have shown that nicardipine, a calcium channel blocker, affects the release of elastase and superoxide anion radicals (O₂ ^–) in vitro during human and rabbit neutrophil respiratory bursts. The drug inhibited the release of elastase and O₂ ^– by fMLP (N-formyl-methionylleucin-phenylalaninin), calcium ionophore (A23187) and PMA (phorbol-myristate-acetate)-stimulated human and rabbit neutrophils. Besides the release of elastase, strongly inhibited in the fMLP and A23187 stimulated systems, nicardipine affected elastase and O₂ ^– in a dose-dependent manner. The corresponding 50% inhibitory concentration (IC₅₀) of nicardipine for elastase, released in PMA-stimulated human and rabbit neutrophils, was 15.95 ± 0.17 M and 18.06 ± 0.08 M, respectively, whereas for O₂ ^–, the IC₅₀ of nicardipine in PMA, fMLP and A23187-stimulated human and rabbit neutrophils was 55.41 ± 0.09 M and 58.43 ± 0.03 M, 45.21 ± 0.13 M and 37.19 ± 0.53 M, 33.54 ± 0.09 M and 30.54 ± 0.29, respectively. The mechanisms underlying the inhibition of elastase and superoxide anion radicals by nicardipine appear related to an inhibiting effect on the mobilisation of cytosolic calcium and on activation of protein kinase C (PKC). These antioxidant and anti-elastasic activities contribute to the properties of nicardipine, as positive side effects of its antihypertensive activity and may be useful to prevent inflammatory disorders (tissue damage, oxidative injury) involved in the pathogenesis of hypertension.