兔胎儿肝脏发育及造血作用的形态学观察

为阐明兔胎儿肝脏发育与造血作用的组织学特征,用4组兔胎儿(平均体长分别为1.9、2.75、4.7 cm和10.35cm)肝脏,经石蜡切片,显微镜观察组织结构变化。结果显示:在1.9 cm组,肝实质已形成几个初级中央静脉,细胞索细胞密度稀疏,索内细胞以卵圆样细胞为主,散在少量多边形细胞,在细胞索间隙充满含有核幼红细胞的造血灶;在2.75cm组,中央静脉增多,肝细胞索细胞密集,窦状隙内以无核红细胞为主,有核幼红细胞减少;在4.7 cm组,中央静脉内皮细胞连续完整,肝细胞索多边形细胞增多,卵圆样细胞减少,索间隙变窄,含有成熟的有核红细胞,造血灶消失;在10.35 cm组,肝细胞索以多边形细胞为主,分散有少量的卵圆样细胞。这些结果表明,1.9 cm胎儿组是肝脏造血作用旺盛时期,2.75 cm胎儿肝脏造血作用减弱,而4.7 cm胎儿已无造血作用。     

发育中后期羊胎儿肺脏显微与超微结构的研究

现今对哺乳动物胚胎发育方面的研究主要侧重于对胚胎早期发育，以及早期胚胎发育的调控因素的研究。而对胚胎着床以后，特别是妊娠中后期胎儿发育的研究报道较少。国内外对胎儿发育中后期肺脏超微结构的研究报道更少，仅检索到一篇关于胎羊围产期肺脏的报道，到目前为止还未发现有对绵羊胎儿肺脏发育过程中组织超微结构的研究报道。本文旨在揭示小尾寒羊妊娠中后期胎羊肺脏组织的发育规律，为早产胎儿的护理提供理论知识，并为研究其他动物胎儿肺脏成熟提供借鉴。     

胚兔牙板发育的形态学观察

用光镜、电镜及特殊染色方法，对胚兔15－25日龄的胚胎发育阶段牙板（dental laminae,DL)进行形态学观察，表明胚兔在发育过程中DL来源于外胚层衍化的上皮，在可能发生牙齿部位，外胚、间充质这些细胞的相互作用（胚胎诱导），为DL发生创造条件，使口腔黏膜上皮向间充质组织增生的DL形成牙胚；在牙胚形成的过程中，DL的牙源性上皮细胞存在着增生与调亡，以调控牙胚发育生理性的稳定及牙齿的数目、形态的异常，进一步表明胚兔DL在发育过程中存在着形成牙齿遗传的潜能及细胞凋亡现象，为研究人类DL形成、分化、结构及颌骨内牙源性肿瘤和牙畸形提供动物模型。     

兔胎儿后肾发育的组织学观察

为阐明兔胎儿肾脏发育的组织学特征,采集四组比利时兔胎儿(平均体长1.9、2.75、4.7 cm和10.35 cm)肾脏,经石蜡切片,显微镜观察肾脏发育变化。结果显示:胎儿体长1.9 cm组肾脏呈果蝇卵型,在肾脏中央可见积聚的5个初级肾小体,远端小管位于其背后方,近端小管位于肾周边;胎儿体长2.75 cm组皮髓质已分化,皮质深层含第1代肾小体,皮质浅层含有分支的输尿管芽及不同发育阶段的肾小体;胎儿体长4.7 cm组皮质增厚,含第1~3代肾小体,浅层皮质类似2.75 cm组;胎儿体长10.35 cm组皮质进一步增厚,含1~7代肾小体,皮质浅层已无输尿管芽及不同发育阶段的肾小体,肾椎体和髓放线明显,肾乳头细长。这些结果表明,兔胎儿肾单位的发育是经输尿管芽的分支,从后肾中央起始向外推移,在皮质浅层大量形成肾单位,到临近出生时肾单位生成停止。     

胚兔牙囊发育生物行为的组织形态学观察

研究胚兔的牙囊发育生物行为与人的牙囊发育是否相似，为人口腔疾病的研究提供模拟实验动物模型，采用光镜、电镜及激光扫描共聚焦显微镜对43只胚兔的牙囊发育过程进行形态学观察。结果显示，牙囊来源于外胚间质，通过胚胎诱导形成牙支持组织，分化产生成牙骨质细胞、成骨细胞、成纤维细胞，形成牙骨质、固有牙槽骨、牙周韧带及其基质，对牙齿发育阶段具有保护和稳定作用，调控未来形成的牙周结构，在早期发育阶段首先出现，与人牙囊发育基本相似；最终牙囊在牙冠的顶部形成索引带，诱导继承牙萌出，在牙冠的根部形成牙支持组织，一部分牙囊细胞有程序性细胞死亡，以维持牙囊发育期内环境的生理平衡。     

热应激对小鼠心脏和肺脏组织形态学的影响

当机体受到来自外界环境的各种刺激时,机体内环境的稳定会受到冲击而发生波动,甚至危及机体的生命过程。此时,机体往往动员其内部力量来克服或消除各种强烈刺激对机体所产生的不良影响。如此一系列旨在提高机体适应能力、维护内环境稳定的非特异性反应称为应激（stress）。而热应激是指机体对于其生理不利的热环境产生的非特异性应答反应的总和。     

胎儿宫内发育迟缓胎盘形态学的研究进展

胎儿宫内发育迟缓(intrauterine growth retardation,IUGR)是发生在多胎动物中的围产期主要并发症之一。胎盘是维系胎儿在子宫内正常发育的重要器官,也是各种致病因素影响胎儿的作用渠道。胎盘形态的病态改变严重损害胎盘正常功能的发挥,从而导致或加剧IUGR的发生。本文对IUGR胎盘的形态变化作一综述,包括胎盘的重量和体积变化,胎盘绒毛的变化、代表母儿交换能力的血管合体膜的变化、代表胎儿血液循环能力的胎盘血管的变化以及标志胎盘缺氧退化的合体结节的异常变化等,以期从形态学上更有效的揭示IUGR的发病机制,从而为制定早期预防措施提供理论依据。     

羊驼胎儿毛囊结构的形态学观察

选择8月龄的羊驼胎儿,颈部取皮肤组织进行石蜡切片,HE染色,观察羊驼胎儿期毛囊形态学结构。结果表明,羊驼胎儿期毛囊在生长过程中的不同结构形态,包括生长期、退化期、静止期以及各期之间的过渡形态结构。生长期的特点是毛球细胞快速增殖,毛乳头包被在毛球内;退化期毛囊底部密封,形成上皮束;静止期整个毛囊的组织结构变短,毛球细胞接近干细胞。     

小鼠软骨发育的形态学观察

应用茜素红—阿利新蓝双重染色技术制作骨与软骨透明标本,观察幼龄小鼠软骨发育的形态学变化。取1、3、5、7、9、15日龄完整幼鼠,水淹致死后去除皮肤、眼、脑、内脏和脂肪组织,乙醇固定,丙酮脱脂,自来水冲洗,茜素红—阿利新蓝混合染色,氢氧化钾透明,各梯度甘油脱水,纯甘油保存。结果小鼠骨骼双重染色硬骨显示为红色,软骨显示为蓝色。随着小鼠日龄的增长,小鼠肋软骨的骨化最为明显,后肢长骨末端的骺软骨板和髋部软骨骨化过程清晰可见。此试验可以清晰的显示不同日龄小鼠肋软骨、后肢关节软骨、髋部软骨的骨化过程。     

Histological development of the small intestinal mucosa in the ovine fetus.

Histological changes in the small intestine of 85 ovine fetuses were studied, with particular reference to the mucosa. In 24-day-old fetuses the endoderm of the intestine consisted of a single layer of epithelium. By the 26th day the epithelium was flattened and stratified. The first evidence of rudimentary villus formation was noted in 39-day-old fetuses. Intestinal glands were first observed at 56 days. Other mucosal structures were present by 101 days. At birth the intestinal mucosa was fully mature.     

Effects of intrauterine crowding on available uterine space per fetus in rabbits

The aim of this study was to examine the effects of uterine crowding on available uterine space per fetus and fetal development at 18 days of gestation in unilaterally ovariectomized and intact does from the sixth generation of a divergent selection experiment on uterine capacity. Uterine capacity was estimated as litter size in unilaterally ovariectomized (ULO) does. Records from 37 ULO and 26 intact does were used. All does were slaughtered on d 18 of gestation. Ovulation rate per side in ULO does was almost twice as much as intact does (12.41 ova vs. 6.47 ova, P < 0.001). ULO does showed higher intrauterine crowding at implantation than intact does (9.36 implanted embryos/uterine horn vs. 5.31 implanted embryos/uterine horn, P < 0.001) and a lower available uterine space per live fetus (3.60 cm vs. 4.44 cm, P < 0.001). The available uterine space per embryo decreased quadratically with the number of implanted embryos (b₁ = − 2.46 ± 0.18, b₂ = 0.13 ± 0.01), and showed a negative linear regression coefficient with number of dead fetuses (− 0.18 ± 0.08). The available uterine space affects quadratically the development of the maternal placenta, and to a lesser extent is linearly related to the development of the fetus and its fetal placenta. The coefficients of these regressions were higher in ULO does than intact does, due to the higher degree of uterine overcrowding in these females.

Although the fetal position within the uterus did not affect the proportion of dead embryos, the uterine position could affect the survival of fetuses with a lower available uterine space. A poor blood supply had a negative effect on survival of the fetus and its development. Probability of death for fetuses with placenta receiving less than 3 blood vessels was higher than those receiving more than 3 blood vessels in both ULO and intact does (75.61% vs. 7.32%). Probability of survival asymptotically increases with available uterine space, as a result of the greater availability of uterine space which allows more blood vessels to reach each implantation site. The uterine overcrowding of ULO does was therefore associated with less uterine space and blood supply available at each implantation site, which could be related to higher fetal mortality in these females. Blood supply also affects fetal development. The implantation sites receiving less than 3 blood vessels showed lighter placentas (1.31 g vs. 1.41 g, P < 0.05) and fetuses (2.02 g vs. 2.12 g, P < 0.05) than those receiving more than 3 blood vessels in both ULO and intact does. These results suggest that available uterine space is a limitation component of fetal survival, which is related to an adequate vascular supply for nutrient exchange from the maternal to fetal blood streams and an adequate surface area for development of the placenta.     

Hemostasis development in the lamb fetus and neonate

Fetal and neonatal lamb hemostasis were studied from the 60th day of pregnancy to birth. Platelet counts and blood coagulation, as assessed by tests such as recalcification time and thromboelastography, were similar in fetuses, neonates, and adult sheep. The values of coagulation factors were low, ie, vitamin K-dependent Factors II, VII, IX, and X remained unchanged (30 and 40% of adult reference values) until the last 10 days of gestation, and then increased until birth (40 to 60%). Values of fibrinogen and Factor V followed a similar pattern, although their activities became identical to adult values at birth. Also, we measured values of protein C and antithrombin III, which are synthesized by the liver. The importance of hepatic failure and fetal vitamin K deficiency were discussed. Factors VIII and XII activities increased gradually during pregnancy to reach adult values at birth. Fetal fibrinolytic activity increased. This could not be explained by the values of tissue-type plasminogen activator (it was not detectable) or by the presence of its fast-acting inhibitor, whose concentration did not decrease.     

Histological lesions in vascular tissues of bovine herpes virus type 4-infected rabbits

The gamma-herpes virus bovine herpes virus type 4 (BoHV-4) is distributed worldwide in cattle populations with unknown pathogenicity. Bovine endothelial cells were recently shown to be susceptible to BoHV-4 infection in vitro and this virus accelerated the cholesterol-induced atherosclerotic process in rabbits. In this study, the in vivo effect of BoHV-4 on cardiovascular tissue was investigated by intravenous infection of rabbits fed a cholesterol free diet. Inflammatory lesions of vascular tissue in aortic and valvular endothelial cells, and smooth muscle cells were detected by H&E staining, PCR, IF, EM immunohistochemistry, while virus isolation was used to detect virus particles. Acute and chronic vasculitis, signs of chronic endocarditis, with mononuclear cell accumulation and a fresh thrombus was found. Herpes viruses have already been thought to initiate cardio-vascular disorders, now this paper shows that a bovine gamma-herpes virus could also be a causative agent of vascular lesions in mammals fed a normal diet. BoHV-4-infection of rabbits could serve as a useful animal model for research into virus-induced human cardio-vascular diseases.     

Functional development of immune response in rabbits

The aim of our study was to extend knowledge concerning postnatal development of the immune system in rabbits from two aspects. Firstly, capability of lymphocytes from peripheral blood, spleen, mesenteric, and popliteal lymph nodes to respond to Concanavalin A stimulation was investigated. Secondly, changes in the ability to produce antibodies against tetanus toxoid by rabbits during maturation were studied. Proliferation of lymphocytes was reduced in mesenteric lymph nodes in newborns, in PB up to the age of two weeks, and in popliteal lymph nodes up to the age of four weeks when compared to adults. High spontaneous lymphocyte proliferation that lasted up to the age of two weeks was recorded in spleen. The study of antibody response showed that even one-day-old rabbits were able to form specific antibodies of isotype IgM and IgG. Nevertheless, significantly lower formation of both isotypes was noted in one-day and two-week-old rabbits, and commencement of IgG isotype formation was delayed in one-day, two-week, and four-week-old rabbits when compared to adults.     

绵羊心壁组织学结构特征的研究

分别制作绵羊左、右心房,左、右心室石蜡组织切片,通过HE、改良PTAH染色法研究绵羊心壁的组织结构特征。结果发现绵羊心壁由心内膜、心肌膜和心外膜构成,心内膜中富含浦肯野纤维;心肌膜最厚,心肌纤维较细,呈螺旋状环绕分层排列;心外膜内可见大量脂肪细胞。改良PTAH染色将肌纤维染成紫蓝色,闰盘着色深蓝,纤维结缔组织染成玫瑰红色。研究结果表明,绵羊心肌纤维较细,肌纤维横纹清晰,闰盘较稀疏。H2O2因其氧化和漂白作用,在改良PTAH染色中有一定的作用。