Expression of the matrix metalloproteinases 2 and 9 in the rat small intestine during intrauterine and postnatal life

The expressions of matrix metalloproteinases 2 and 9 have been described during the development, as an example in heart and tooth but not in the small intestine yet. In this context, this study aimed to evaluate the expressions of MMP-2 and MMP-9 in the small intestine of Wistar rats during intrauterine (IU) and postnatal (PN) life. Expressions were determined on the 15th and 18th days of IU life and the 3rd, 10th, 17th, 25th, and 32nd days of PN life. Intestinal samples obtained from six animals were submitted to zymography, immunohistochemistry, and staining with Masson's trichrome. The results showed that MMP-2 and MMP-9 were not expressed during IU life; however, after birth, MMP-9 was immunolocalized in the goblet and mast cells. In conclusion, our results showed that MMP-2 and MMP-9 were not expressed in absorptive epithelial cells during the IU period of the small intestine but after birth, MMP-9 was expressed in the goblet cells, and mast cells present in the lamina propria.     

实验性过敏性脑脊髓炎豚鼠脊髓病理学及Bcl-2 和Bax蛋白表达的研究

目的:通过观察实验性过敏性脑脊髓炎(EAE)豚鼠脊髓内的病理改变及Bcl-2和Bax蛋白的表达,探讨EAE发病中影响细胞凋亡的机制。方法:采用完全弗氏佐剂和豚鼠脊髓匀浆诱发实验性过敏性脑脊髓炎(EAE)豚鼠模型,动物分别存活14d和28d后取脊髓颈膨大和腰骶膨大段,石蜡切片,HE染色和免疫组化ABC法染色,光镜观察。结果:HE染色发现:除典型的脊髓白质小血管周围的炎性细胞浸润外,在脊髓腹侧静脉、脊髓背侧静脉和沟静脉等较大血管周围也有炎性细胞浸润,28d较14d严重。免疫组化染色发现:模型组脊髓病灶部位和非病灶部位Bcl-2阳性细胞的表达均高于正常组,第28d模型组Bcl-2阳性细胞的表达数目明显高于第14d,模型组Bax阳性细胞的表达比正常组高,在病灶部位Bax的表达第28d高于第14d,而在非病灶部位两个存活期差别不大。结论:实验提示与细胞凋亡密切相关的基因蛋白Bcl-2和Bax参与EAE的发病过程。     

Immunological studies on tartrazine and its metabolites. I. Animal studies

Tartrazine is occasionally associated with some clinical changes which have been attributed to allergy. In tests on laboratory animals with tartrazine and its metabolites by methods which should have detected potential to induce antibody formation, no antibodies were detected except by methods which are artificial in terms of human exposure. Similarly, laboratory methods have shown that the metabolites of tartrazine, and in some cases tartrazine itself, can induce contact sensitization in guinea pigs, although there is little evidence that tartrazine can induce similar changes in man.     

小肠缺血再灌注损伤导致Cajal间质细胞凋亡的实验研究

目的探讨小肠缺血再灌注损伤对Cajal间质细胞（interstitial cells of Cajal,ICC）的影响。方法采用缺血60 min再灌注6 h（I60/R6h）、12 h（I60/R12h）和14 d（I60/R14d）的豚鼠小肠,通过免疫细胞化学和TUNEL法检测ICC的凋亡。结果I60/R6h豚鼠小肠可见少量TUNEL阳性ICC。I60/R12h可见较多的凋亡ICC,同时ICC细胞数量明显减少,细胞网络不完整。I60/R14d的ICC恢复正常数量和分布。不同时间点之间Kit/TUNEL双标阳性细胞数量存在显著差别（P〈0.05）。结论小肠缺血再灌注损伤导致ICC凋亡,一段时间后ICC能够恢复正常。     

Species difference in mechanisms of D-xylose absorption by the small intestine

Comparisons were made for the ability of D-xylose to evoke changes in the transepithelial potential difference upon its addition to the mucosal solution between guinea pig and rat small intestines. Also, Na+-dependence of D-xylose influx from the mucosal solution into epithelial cells, and the phlorizin-sensitivity of the influx, were compared between these animals. In guinea pig intestine, the sugar caused an immediate and sustained increase in the transmural potential difference, and this potential increment was completely abolished by phlorizin. In contrast, the sugar did not cause any electrical changes in the rat small intestine. The influx of D-xylose across the mucosal border was Na+-dependent and phlorizin-sensitive in guinea pigs, while it was Na+-independent and phlorizin-insensitive in rats. The results indicate that there is a qualitative difference in the mode of transport of D-xylose between guinea pigs and rats.     

Prenatal and postnatal development of the small intestine in the insectivore Suncus murinus

The development of the small intestine in the insectivore Suncus murinus was noted during the period from 21 days' gestation to 20 clays after birth. At 21 days of gestation, the proximal small intestine exhibited the beginning of villus formation, whereas the distal small intestine preserved the stratified epithelium. Stratified epithelium in the distal small intestine changed into a single layer by 24 days' gestation. At 26 day's gestation, each epithelial cell was immature; but by 28 days mature-looking epithelial colls were found. The shape of the villi changed from cuboid to columnar during the same period. The connective-tissue cores of the villi began to develop at 7 days after birth in the proximal small intestine and at 15 days after birth in the distal small intestine. Crypts appeared at 15 days after birth. Endocytosis of epithelial cells took place at 28 days of gestation. In the proximal small intestine, supranuclear vesicle clusters were observed first at birth; they began to decrease both in number and size at 10 days' gestation and then disappeared completely by 20 days after birth. In the distal small intestine, large supra-nuclear vacuoles were observed first at 28 days of gestation. Although these vacuoles invariably were found up to 15 days after birth, they also disappeared completely by 20 days. Epithelial cells showed a structure similar to those of the adult after weaning.     

Host specificity of enteropathogenic Escherichia coli from rabbits: lack of correlation between adherence in vitro and pathogenicity for laboratory animals.

The pathogenicity of four attaching and effacing strains of enteropathogenic Escherichia coli originally isolated from diarrheic rabbits was investigated by inoculating them perorally into rabbits, guinea pigs, and mice. The ability of the four strains to adhere to cultured epithelial cells, erythrocytes, and intestinal brush borders from various animal species, including rabbits, guinea pigs, and mice, varied considerably. Only one strain carried AF/R1 fimbriae, which are believed to determine the host specificity of these bacteria. Despite these differences, the pattern of behavior of the four strains in experimentally infected animals was similar. Each strain caused fatal diarrhea in rabbits (although the virulence of individual strains for rabbits differed significantly), and none was virulent for guinea pigs or mice. None of the strains colonized the intestinal tract of guinea pigs, but all were able to cause attaching-effacing lesions in ligated loops of guinea pig small intestine. By contrast, all four strains colonized mice, in particular the distal intestine, but none induced attaching-effacing lesions in mouse intestinal loops. These findings suggest that there may be previously unrecognized host-restricted adhesins in enteropathogenic E. coli and indicate that adherence to erythrocytes or intestinal brush borders in vitro does not necessarily reflect colonizing ability or pathogenicity in vivo.     

Experimental infection of piglets with a korean strain of porcine epidemic diarrhoea virus

Thirty colostrum-deprived piglets aged 1 day were inoculated with a Korean strain of porcine epidemic diarrhoea virus (PEDV). The purpose was to elucidate the pathogenicity and viral distribution in PEDV-infected piglets over a period of 60 h, by morphometric analysis, in-situ hybridization and immunohistochemistry. At 24-60 h post-inoculation (hpi), the villous height/crypt depth (VH/CD) ratio of infected pigs was significantly less than that of control pigs. Positive cells typically exhibited a dark black reaction product (in-situ hybridization) or brown reaction product (immunohistochemistry) in the cytoplasm, without background staining. PEDV nucleic acid and antigen were detected in the duodenum, jejunum and ileum of experimentally infected pigs. The results suggested that the Korean strain was virulent and caused severe villous atrophy in the small intestine.     

Prenatal development of “synaptic” ribbons in the guinea pig pineal gland

Pineal “synaptic” ribbons are a heterogeneous population of organelles. “Synaptic” ribbons (SR) sensu stricto, “synaptic” spherules (SS), and intermediate forms (IMF) are present. Their function and origin are unknown, and a knowledge of their prenatal development is lacking. Thus the pineal glands of prenatal, neonatal, and adult guinea pigs were prepared for electron microscopy. “Synaptic” ribbons were studied morphologically and quantitatively. The three categories of “synaptic” ribbons reported in adult pineal glands were also present in prenatal pineal glands. Their structural features, distribution, grouping, and composition patterns are similar to those in adults. “Synaptic” ribbons were first detected in pinealocytes of the distal region of a 42-day postcoitus (PC) pineal gland and were comparable with those in adults. They increased in number with age and reached a peak at 63 days PC, followed by a steep decline at 66 and 67 days PC. By day 69 PC, the numbers increased again and showed a dramatic increase after birth. Several true ribbon synapses were seen at day 63 PC between pinealocyte cell processes or between pinealocyte cell process and pinealocyte cell body. Since true ribbon synapses have not been found in adult guinea pig pinealocytes, their synaptic nature could have been lost during development. No precursors for the “synaptic” ribbons were found. The endoplasmic reticulum cisternae may be the origin for the ribbon vesicles because of their close association with the “synaptic” ribbons.     

Pathogenesis of a Chinese strain of bovine adenovirus type 3 infection in albino guinea pigs

Bovine adenovirus type 3 (BAV-3) is considered one of the most important respiratory tract agents of cattle and is widespread among cattle around the world. A BAV-3 strain was isolated from a bovine nasal swab for the first time in China in 2009 and named HLJ0955. Subsequently, BAV-3 has frequently been isolated from calves with respiratory diseases in China. To date, only limited study on the pathogenesis of BAV-3 infection in cotton rats has been conducted, and the pathogenesis of BAV-3 infection in guinea pigs has not been reported. Therefore, sixteen albino guinea pigs were inoculated intranasally with HLJ0955. All of the infected guinea pigs had apparently elevated rectal temperatures (39.2 °C–39.9 °C) at 2–7 days post-inoculation (PI). Consolidation and petechial hemorrhage were also observed in guinea pigs experimentally infected with HLJ0955. Viral replication was detectable by virus isolation and titration and by immunohistochemistry in the lungs of guinea pigs as early as 24 h PI. Viral DNA was detectable in the lungs of infected guinea pigs during 11 days of observation by real-time PCR. Virus-neutralizing antibodies against BAV-3 were detectable from 11 days PI and reached a peak titer at 15 days PI. Histopathological changes mainly occurred in the lungs of infected guinea pigs and were characterized by thickening of alveolar septa, mononuclear cell infiltration, hemorrhage and alveolar epithelial necrosis. These results indicate that HLJ0955 can replicate in the lungs of guinea pigs and cause fever and gross and histological lesions. The guinea pig infection model of BAV-3 would serve as a useful system for monitoring the infection process and pathogenesis of the Chinese BAV-3 strain HLJ0955, as well as immune responses to BAV-3 vaccines.     

Hylan G-F 20 induces delayed foreign body inflammation in Guinea pigs and rabbits

Recent clinical evidence suggests that hylan, a modified hyaluronan, and related products potentially elicit foreign body granulomatous inflammation in human soft tissue. We investigated the biocompatibility of hylan G-F 20 (Synvisc) for up to 28 days after intradermal injection in guinea pigs and intramuscular injection in rabbits. Compared to saline and unmodified hyaluronan, hylan induced definitive macroscopic changes in guinea pigs by day 14 or later and in rabbits by 28 days after injection. Histologically, at the injection sites, there was severe granulomatous inflammation in guinea pigs and acute inflammation with minimal infiltration of macrophages and foreign body giant cells in rabbits. Furthermore, specific antibodies against hylan were demonstrated in guinea pigs by passive cutaneous anaphylaxis, and substantial deposits of IgG on hylan were evident by immunohistochemistry. The present results contradict previous reports on biocompatibility of hylan and suggest that hylan may potentially induce similar unfavorable reactions in humans.     

大鼠单叶肝去细胞生物支架的制备与鉴定

目的通过灌注法制备大鼠单叶肝去细胞生物支架,并对其进行鉴定。方法健康成年SD大鼠20只,随机分为去细胞组和正常对照组,每组10只。去细胞组经门静脉灌胃针插管,恒温37℃依次灌注肝素化PBS溶液,1%Triton X-100(p H 7.5~8.0)及PBS溶液。HE、Masson染色及扫描电子显微镜观察组织学及超微结构改变;免疫荧光结合4’,6-二脒基-2-苯基吲哚(DAPI)观察2组胶原蛋白Ⅳ和Ⅰ、层黏连蛋白和纤维连接蛋白观察细胞外基质的主要成分;DNA定性和定量分析组织中残留DNA浓度和片段长度;聚甲基丙烯酸甲酯铸型观察肝脏内血管分布情况。结果 Triton X-100灌注4h左右即可制备单叶肝脏去细胞生物支架。在灌注过程中,肝内细胞和细胞碎片逐渐被清洗,最终变成半透明状。HE、Masson、免疫荧光染色及扫描电子显微镜显示,去细胞组肝生物支架较完整地保留了细胞外支架的成分,未见明显细胞及细胞核成分残留;去细胞组支架DNA残留量较正常对照组下降了97.32%,琼脂糖凝胶电泳未见明显的DNA条带。血管铸型标本显示,去细胞组血管分布与正常对照组相仿,其分支完整、清晰。结论运用Triton X-100灌注法所制备的大鼠单叶肝生物支架去细胞彻底,较完整地保留细胞外基质和血管网络结构,是一种简单易行且较为理想的制备实验用单叶肝生物支架的方法。     

Age-related changes in gallbladder contractility and gallbladder cholecystokinin receptor population in the guinea pig

We have examined the effects of aging on guinea pig biliary motility both in vitro and in vivo. The first experiment compared contractile tension of gallbladder strips from young adult (6-12 months old) and 3-year-old guinea pigs in vitro. Contraction of gallbladder strips from the young guinea pigs was twice as forceful and was more sensitive to octapeptide of cholecystokinin (CCK-8) stimulation than the gallbladder strips from the older guinea pigs. The two groups were also studied in vivo by measuring changes in the intraluminal pressure of the gallbladder in response to exogenously administered doses of CCK-8. Young adult guinea pigs were more sensitive to CCK-8 at the lower doses tested and demonstrated gallbladder contractions that were more forceful than that of the old guinea pigs. CCK receptors were measured on gallbladder muscularis membranes from young adult and old guinea pigs. The number of receptors on gallbladder membranes decreased with age: 65.0 +/- 17.7 fmoles/mg protein on membranes from 1 year old; 7.9 +/- 2.0 fmoles/mg protein on membranes from 3 years old. The binding affinity of CCK receptors on gallbladder muscularis membranes for binding to CCK-8 was not significantly different in the two age groups studied. We conclude that age-related decreases in gallbladder responses to CCK-8 may be due to decreased concentrations of CCK receptors on gallbladder muscle cells.     

Mechanism of Action of the Enteropathogenic Factor of Clostridium perfringens Type A

Cell extract of an enteropathogenic strain of Clostridium perfringens type A was administered intravenously to lambs, rabbits, and guinea pigs. Lambs developed transitory diarrhea, lacrimation, salivation, nasal discharge, lassitude, and dyspnea in 1 to 5 hr after inoculation. Large doses of the inoculum caused rapid onset of the clinical signs and subsequent death. Examination of dead animals revealed intensely hyperemic small intestinal mucosa and some congestion in the liver, lungs, spleen, and kidneys. Rabbits showed excessive salivation, frequent defecation, tranquility, and dyspnea, followed by death. Guinea pigs became weak and died in 15 min to 7 hr. Congestion was evident in lungs, liver, spleen, and in the small intestine. In lambs and guinea pigs tested, atropine and epinephrine alleviated the clinical signs. Intradermally injected cell extract caused an immediate increase in capillary permeability and subsequent erythematous reaction without necrosis in the skin of guinea pigs. It is hypothesized that in the enteric infection C. perfringens enteropathogenic factor acts on the small intestine causing increased capillary permeability, vasodilation, and increased intestinal motility.     

Post-natal development of the median eminence of the guinea pig.

The ultrastructure of the median eminence of neonatal (newborn) 1-, 3-, 5-, and 10-day old) and adult guinea pigs was studied to determine the dynamic changes occurring in this structure during early life. At birth the portal vasculature consists of the Mantelplexus and a few, non-fenestrated capillary loops. The number of ansae and the degree of fenestration increase rapidly after birth. The abundance of cytoplasmic and ciliary projections into the ventricular recess and the large numbers of organelles indicate that the ependymal cells are more active in the neonatal period than in the adult male. Moreover, the ependymal endfeet cover most of the surface area of the primary portal plexus during this time. The neuronal layers of the median eminence are difficult to distinguish at birth due to the lack of myelinated fibers in the zona interna. Significant myelination appears on day 3 but is not complete until day 10. There is a progressive increase in the numbers of Herring bodies and large neuro-secretory granules (1,500-1,700 A) during this same time period. In the zona externa, few nerve terminals abut on the perivascular space until day 3. Increases in numbers of granules per axon profile were noted for each day after birth. Despite the relatively long gestation period of the guinea pig (68-72 days), the morphologic appearance of the median eminence at birth suggests that the neurovascular link controlling anterior pituitary function is not yet complete.     

Post-natal development of the median eminence of the guinea pig

The ultrastructure of the median eminence of neonatal (newborn, 1-, 3-, 5-, and 10-day old) and adult guinea pigs was studied to determine the dynamic changes occurring in this structure during early life. At birth the portal vasculature consists of the Mantelplexus and a few, non-fenestrated capillary loops. The number of ansae and the degree of fenestration increase rapidly after birth. The abundance of cytoplasmic and ciliary projections into the ventricular recess and the large numbers of organelles indicate that the ependymal cells are more active in the neonatal period than in the adult male. Moreover, the ependymal endfeet cover most of the surface area of the primary portal plexus during this time. The neuronal layers of the median eminence are difficult to distinguish at birth due to the lack of myelinated fibers in the zona interna. Significant myelination appears on day 3 but is not complete until day 10. There is a progressive increase in the numbers of Herring bodies and large neurosecretory granules (1,500-1,700 Å) during this same time period. In the zona externa, few nerve terminals abut on the perivascular space until day 3. Increases in numbers of granules per axon profile were noted for each day after birth. Despite the relatively long gestation period of the guinea pig (68-72 days), the morphologic appearance of the median eminence at birth suggests that the neurovascular link controlling anterior pituitary function is not yet complete.     

Cryptosporidiosis in guinea pigs: an animal model.

Cryptosporidia from natural cryptosporidiosis in guinea pigs were experimentally transmitted to both adult and juvenile guinea pigs. Cryptosporidia were associated with the villi of the ileum, jejunum, and duodenum. Both juveniles and adults were equally susceptible to cryptosporidia, as determined by decreases in villus height, increases in crypt depth, and decreases in villus height/crypt depth ratios, when compared with uninoculated animals. When multiple paired comparisons were made between 2 and 10 days postinoculation, there were significant decreases in villus height/crypt depth ratios with time. A dose study showed that 6-week-old guinea pigs were all infected with doses as low as 325 oocysts per animal. When sampled at weekly intervals postinoculation, guinea pigs had significant evidence of infection up to 2 weeks but had recovered completely by 4 weeks. Guinea pigs mounted a specific humoral immune response against cryptosporidia, as measured by an immunoperoxidase technique. Guinea pigs challenged by reinoculation with cryptosporidial oocysts were completely refractory to reinfection. These studies show that cryptosporidiosis in guinea pigs is a useful small animal model of this disease.     

Effects of microflora on the neonatal development of gut mucosal T cells and myeloid cells in the mouse

Colonization with commensal flora in very early life may profoundly influence intestinal lymphoid development and bias later immune responses. We defined gut-homing T cell phenotypes and the influence of flora on intestinal immune development in mice. Intestinal T cells were phenotyped and quantified in conventional (CV), germfree (GF) and conventionalized germfree (GF/CV) neonatal mice by immunohistochemistry. Mucosal adressin cell adhesion molecule 1 (MAdCAM-1) was expressed by mucosal vessels at birth in CV and GF mice and was more prevalent in CV than GF small intestine, but was distributed similarly and did not change with age. Less MAdCAM-1 was expressed in the colon; its distribution became restricted after weaning, with no difference between CV and GF mice. CD3(+)beta(7) (+) cells were present in similar numbers in CV and GF intestine at birth. They were CD62L(-) in CV mice and were accompanied by further CD3(+)beta(7) (+)CD62L(-) T cells as development progressed, but in GF and GF/CV intestine they expressed CD62L and numbers did not change. IEL numbers increased at weaning in CV mice in both small and large intestine, but showed delayed development in GF intestine. Macrophages were present at high levels from birth in GF intestine, but dendritic cells did not develop until day 16. Thus, fetus-derived T cells seed the intestinal lamina propria before birth via beta-MadCAM interactions. Their activation status depends on the microbiological status of the dam, and without a commensal flora they remain naive. We propose that these cells regulate antigen responsiveness of the developing mucosal T cell pool.     

胚胎时期小鼠小肠的组织发生

目的　观察小鼠胚胎各个时期小肠组织的形态结构及杯状细胞在小肠内的分布规律,为小鼠小肠的组织发生提供形态学依据。 方法　采用HE染色和PAS染色,对小鼠胚胎第13.5天（E13.5d）至出生后第1天（P1d）胚胎的石蜡切片染色并行光学显微镜观察。 结果　(1)小鼠肠壁于E13.5 d已分化出现黏膜层、黏膜下层、肌层及浆膜。(2)肠绒毛于E15.5 d分化形成,杯状细胞于E16.5 d逐渐发育分化出现,肠腺于E18.5~P1 d发育分化形成,此时小肠基本结构形成。(3)杯状细胞主要分布于小肠绒毛上皮,其中以回肠末端最多,回肠、空肠、十二指肠顺次递减（P<0.05）。杯状细胞数量随胎龄逐渐增加而逐渐增多,于P1 d最多（P<0.05）。 结论　小肠上皮分化于E15.5 d至E17.5 d最为迅速,胚胎时期小肠基本结构形成,其吸收消化功能基本建立完成。     

豚鼠胆囊胆固醇结石形成过程中肠道传输功能下降的细胞及分子机制探讨

目的探讨豚鼠胆囊胆固醇结石形成过程中肠道传输功能下降的细胞和分子机制及其与胆石形成的关系。方法健康雄性豚鼠40只,4周龄,体质量120～125g。将其随机分为实验组与对照组,每组20只。实验组给予致石饲料（胆固醇含量2%）,对照组给予正常颗粒饲料。8周造模结束后,用逆转录聚合酶链反应（RT-PCR）检测小肠组织中c-kit及scf的mRNA的表达情况,利用末端回肠全层铺片免疫荧光化学染色及激光共聚焦显微镜观察各组Cajal样间质细胞（ICCs）数量的变化。结果 RT-PCR结果显示,与对照组相比,实验组豚鼠小肠c-kit（0.316±0.056vs0.912±0.103;t=6.582,P〈0.01）和scf（0.499±0.012 vs 0.899±0.124;t=6.163,P〈0.01）的mRNA水平的表达量下降;对照组豚鼠回肠ICCs平均阳性面积为（56.24±2.68）%,实验组为（22.26±1.14）%,较对照组明显降低（t=15.256,P〈0.01）。结论饮食诱导的豚鼠胆囊胆固醇结石形成过程中,小肠c-kit和scf基因mRNA表达水平下降,ICCs数量明显减少。c-kit/scf通路抑制可能参与胆囊胆固醇结石的形成过程中肠道传输功能下降的发生。