Muscle cells become necrotic rather than apoptotic during reperfusion of ischaemic skeletal muscle

While necrosis is known as a major mechanism for the loss of viability of skeletal muscle following ischaemia and reperfusion, much less is known of the role of apoptosis. In this study rat hind limbs were subjected to 2 h of tourniquet ischaemia, then reperfused for either 0, 0.25, 0.5, 1, 3, 8, 16 or 24 h (n = 6 per group). Mean viability of muscle, assessed by tetrazolium dye reduction, after 2 h ischaemia and 24 h reperfusion was 17%. Histological examination revealed disrupted, necrotic muscle fibres from 30 min to 24 h reperfusion. Apoptotic nuclei were identified by haematoxylin staining and TUNEL, terminal deoxynucleotidyl transferase mediated dUTP nick end labelling. No TUNEL-positive cells were observed at the end of the ischaemic period, but a small number of TUNEL-positive endothelial and smooth muscle cells were found at 30 min reperfusion, with a progressive increase in their number up to 24 h reperfusion. Apoptotic neutrophils were detected after 8-24 h reperfusion. At no stage was apoptosis seen in the nuclei of skeletal muscle fibres. It appears that apoptosis plays no role in the death of muscle fibres after ischaemia-reperfusion injury to skeletal muscle.     

休克小肠再灌注损伤的研究Ⅰ.休克小肠的再灌注损伤

为研究缺血小肠的再灌注损伤,阻断家兔SMA血流1小时或35mmHg低压灌流SMA2小时,然后以90mm Hg恒压再灌注2小时。结果发现缺血小肠再灌注后出现逐渐加重的组织损伤,表现为血浆ACP活性、乳酸和镁进行性增加,小肠粘膜出血,小肠绒毛坏死和组织水肿进行性加重,以及体动脉压降低,心肌缺血损伤等。这种再灌注损伤,甚至比小肠持续缺血3小时者更严重。本文对缺血小肠再灌注损伤在休克发病学中的意义进行了讨论。     

Regional contractile blockade at the onset of reperfusion reduces infarct size in the dog heart

An important mechanism of lethal myocardial reperfusion injury is the development of cellular hypercontracture at the onset of reperfusion. Hypercontracture can lead to cytolysis by mutual mechanical disruption of myocardial cells. 2,3-Butanedione monoxime (BDM) inhibits myofibrillar cross-bridge cycling and may therefore reduce infarct size in ischaemic reperfused myocardium. This study investigated whether a temporary presence of BDM protects against myocardial reperfusion injury in an intact-animal preparation. Anaesthetized open-chest dogs (n=10) underwent 1 h of left anterior descendent artery (LAD) occlusion and received intracoronary BDM (25 mM, n=5) or vehicle (n=5) for 65 min starting with an anoxic local infusion 5 min before reperfusion. Infarct size was assessed by triphenyltetrazolium staining after 6 h reperfusion. The infusion of BDM was accompanied by a transient reduction of left ventricular systolic pressure from 84.3±11.2 mm Hg during occlusion to 66.4±9.9 mm Hg at 30 min reperfusion (mean±SD, P<0.01 vs. control). LAD-flow and regional wall motion in the area at risk showed no difference between groups. Infarct size (% of area at risk) was reduced from 24.4±8.7 (control) to 6.6±2.0% (BDM) (P<0.01). The results demonstrate that development of necrosis in reperfused myocardium can be greatly reduced by temporary presence of the contractile inhibitor BDM at the onset of reperfusion.     

Relationship between dose of methotrexate, apoptosis, p53/p21 expression and intestinal crypt proliferation in the rat

Abstract Previous studies have shown that apoptosis is induced by cytotoxic chemotherapy and precedes hypoproliferation of intestinal crypt cells. However, the relationship between the degree of intestinal apoptosis and crypt cell hypoproliferation may not be directly related. The purpose of this study was to investigate the relationship between apoptosis and hypoproliferation with increasing doses of chemotherapy. Eleven groups of breast cancer-bearing DA rats were treated with two doses of methotrexate (MTX) i. m. at varying concentrations (0.5, 1.5, 2.5 and 5.0 mg/kg) or saline (control). Animals were killed at 6 or 24 h following treatment. The small and large intestines were examined for apoptosis, villous area (small intestine), crypt length and mitotic count per crypt. Immunohistochemical expression of p53 and p21^waf1/cip1 (p21) were examined quantitatively. Data were analysed using Peritz F-test. Low dose MTX (0.5 mg/kg) did not change p53 expression at 6 h but induced a 15-fold increase in apoptosis in the crypts of the small intestine. This was associated with only a minor reduction in crypt cell proliferation. Higher doses of MTX increased p53 expression and caused a lower (7-fold) but more prolonged peak of apoptosis that was accompanied by reduced villous area, shortened crypts and a more profound reduction in crypt cell proliferation. Unlike the small intestine, apoptosis in the colon was 10-fold lower, proportional to the dose of MTX and did not induce overt damage. Expression of p21 did not change with any dose at either timepoint. We conclude that apoptosis is not always associated with crypt cell hypoproliferation and that the small intestine can recover after low dose MTX despite a heightened peak of apoptosis of crypt cells.     

The significance of cytological examination on reperfusion in rat small intestinal transplantation

We examined the cytology of the exudate in preserved intestinal grafts on reperfusion and compared it with the histological findings in rat small intestinal transplantation. The jejunal graft was harvested from the Lewis rat and was preserved in University of Wisconsin solution for 6, 12, 24 and 48 h at 4 °C (n=6, in each group) and was then syngeneically transplanted. On reperfusion, the exudate was collected and studied cytologically. Full thickness biopsies were performed at the end of the preservation and at 30 min after reperfusion for histological examination. Histological examination after reperfusion showed that the crypt layer was preserved until 24 h. However, it was destroyed by 48 h preservation. The cytological findings correlated with the depth of tissue injury shown histologically. The degeneration of villus epithelial cells, the decrease in the content of mucin in both the goblet cells as well as villus cells, and the appearance of crypt cells are all considered to be signs of poor graft viability. Cytological examination is therefore recommended as an effective, non-invasive and real-time method for evaluating graft viability just after reperfusion in small intestinal transplantation.     

骨髓间充质干细胞移植保护小肠缺血再灌注损伤

BACKGROUND: Bone marrow mesenchymal stem cells have good proliferation and paracrine functions, which have irreplaceable advantages in the treatment of intestinal diseases. OBJECTIVE: To explore the effects of bone marrow mesenchymal stem cell transplantation on intestinal ischemia-reperfusion injury in rats. METHODS: Forty-eight Sprague-Dawley rats were enrolled to make animal models of ischemic reperfusion injury of the intestine, and then model rats were randomized into experimental and control groups. After modeling, 1 mL bone marrow mesenchymal stem cells or the same volume of normal saline were injected into the intestinal mucosa of rats in the two groups, respectively. At hours 0, 2, 6, 24, 72, 120 after injection, serum diamine oxidase, tumor necrosis factor α, and D-lactic acid levels were detected by ELISA method. At 24 hours after injection, rat intestinal tissues were taken and observed pathologically under light microscopy, and their close connections were observed under transmission electron microscope. ZO-1 protein levels were detected by immunohistochemistry method. RESULTS AND CONCLUSION: Compared with the control group, the serum diamine oxidase, tumor necrosis factor α, and D-lactic acid levels were significantly lower in the experimental group at hours 6 and 24 after injection (P < 0.05). Intestinal necrosis, villous edema, intestinal congestion and inflammatory cell infiltration in the experimental group were milder than those in the control group. In addition, the ZO-1 protein expression in the experimental group was higher than that in the control group. Experimental results show that bone marrow mesenchymal stem cell transplantation into the intestinal mucosa can improve the intestinal mucosal permeability in rats with intestinal ischemia-reperfusion injury.      

Interleukin-6/soluble interleukin-6 receptor complex reduces infarct size via inhibiting myocardial apoptosis

Apoptosis of cardiomyocytes plays an important role in reperfusion injury following myocardial infarction. Conversely, interleukin-6 (IL-6)--a potent cytokine--inhibits myeloma cell apoptosis by activating GP130 through the IL-6 receptor (IL-6R). We hypothesized that the IL-6/soluble IL-6R complex can inhibit myocardial apoptosis, and limit infarct size in reperfused acute myocardial infarction. Anesthetized rats were randomly divided into five groups: sham, coronary occlusion and reperfusion rats administered IL-6/soluble IL-6R complex, IL-6 alone, soluble IL-6R (sIL-6R) alone, or a control vehicle. Rats were subjected to 30 min occlusion of the left coronary artery followed by 3 h reperfusion. After reperfusion, the hearts were excised. For detection and quantification of apoptosis, gel electrophoresis of extracted genomic DNA and TUNEL method of paraffin sections were performed. The percentage of the infarct area was measured using tetrazolium chloride staining. The cardiomyocyte apoptosis analysis revealed that apoptosis in the reperfused myocardium was inhibited only in the complex group. Furthermore, the percentage of the infarct area out of the area at risk was remarkably reduced in the complex group (23.8+/-1.8%), compared with that in the vehicle (37.9+/-3.7%), the IL-6 (40.7+/-1.0%), or the sIL-6R (37.5+/-2.4%) groups (P=0.0002). No significant differences were observed among the vehicle, IL-6, and sIL-6R groups. The IL-6/soluble IL-6 receptor complex inhibits cardiomyocyte apoptosis in reperfused acute myocardial infarction. It possibly reduces irreversible reperfusion injury.     

三七总皂甙降低兔肺缺血再灌注损伤和抑制细胞凋亡

 目的: 探讨细胞凋亡与肺缺血再灌注损伤的关系以及三七总皂甙的作用及机制。方法: 健康日本大耳白兔84只,随机分为对照组、肺缺血再灌注1、3、5h组和相应三七总皂甙干预组。复制肺缺血再灌注损伤模型。用原位缺口末端标记(TUNEL)法、聚丙烯酰胺凝胶电泳观测肺组织细胞凋亡,原位杂交技术检测肺组织细胞Fas/FasL系统和Caspase-3基因表达。结果: 肺缺血再灌注组肺组织细胞凋亡指数(肺缺血再灌注5h组:22.08±1.93;对照组:2.04±0.67)、Fas/FasL和Caspase-3基因表达(肺缺血再灌注5h组:0.241±0.029;对照组:0.121±0.015)均显著高于对照组(P<0.01),并出现电泳梯形条带结构;三七总皂甙干预组Fas/FasL mRNA及其Caspase-3的表达(三七总皂甙干预5h组:0.199±0.020;肺缺血再灌注5h组:0.241±0.029)显著低于缺血再灌注组(P<0.01),肺组织细胞凋亡指数(三七总皂甙干预5h组:12.58±1.82;肺缺血再灌注5h组:22.08±1.93)也显著低于缺血再灌注组(P<0.01),梯形条带结构基本消失。肺组织细胞凋亡指数分别与Caspase-3 mRNA及Fas/FasL mRNA之间均呈显著正相关(P<0.01)。结论:三七总皂甙可能通过抑制Fas/FasL系统的激活,阻遏肺组织细胞凋亡,从而减轻肺缺血再灌注损伤。     

Anti-CD3 induces bi-phasic apoptosis in murine intestinal epithelial cells: possible involvement of the Fas/Fas ligand system in different T cell compartments

Recent studies have suggested that Fas-mediated apoptosis is involved in the pathogenesis of intestinal injury. In this study, we determined the role of Fas/Fas ligand (FasL) interactions in different T cell compartments using a murine model of small intestinal injury. An intraperitoneal injection of 145-2C11 (anti-CD3) antibody into C3H/HeN, BALB/c and MRL mice induced mucosal flattening and rapid, bi-phasic intestinal epithelial cell (IEC) apoptosis, which was detected by conventional light and electron microscopy and by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling. In the first, early phase, villous apoptosis was observed up to 4 h after injection, and in the second, later phase, apoptotic crypt cells gradually accumulated for up to 24 h. The early and later phases of apoptosis were reduced in lpr/lpr and nude mice compared with those in control strains. In addition, the kinetics of Fas-mediated killer activity induced by the antibody injection were different between intestinal intraepithelial lymphocytes (IEL) and splenocytes (SPL) and seemed to correlate with the bi-phasic occurrence of the apoptosis. Finally, the transfer of intestinal IEL from euthymic to nude mice induced both phases of apoptosis, whereas SPL induced the second phase's crypt apoptosis only by the antibody injection. Together, these results suggest the involvement of Fas-mediated killer activity of thymus-derived T cells in different compartments. Namely, T cell populations in different compartments are differentially involved in the induction of IEC apoptosis and contribute to the complex pathogenesis of immune-mediated intestinal injury in which Fas/FasL interactions may play a critical role.     

再灌注前干预肥大细胞功能对大鼠肠缺血再灌注后早期肝损伤的影响

 目的：探讨肠缺血后再灌注前干预肥大细胞功能对SD大鼠继发肝脏损伤的影响及机制。方法：35只大鼠随机分成5组：假手术组（S组）、缺血再灌注组（IR组）、缺血再灌注＋色甘酸钠组（IR+C组）、缺血再灌注＋酮替芬组（IR+K组）和缺血再灌注＋compound 48/80 组（IR+CP组）。复制大鼠肠缺血再灌注模型,IR+C、IR+K和IR+CP组分别在再灌注前5 min经尾静脉给予相应药物,S和IR组给予等量生理盐水。再灌注4 h后处死大鼠,观察各组肝脏病理变化及评分,测定血清丙氨酸氨基转移酶（ALT）活性、天冬氨酸氨基转移酶（AST）活性和组胺含量,检测肝脏乳酸脱氢酶（LDH）活性、丙二醛（MDA）含量、超氧化物歧化酶（SOD）活性和肿瘤坏死因子α（TNF-α）、白细胞介素8（IL-8）水平。结果：与S组相比,IR组肝脏病理损伤明显（P<0.05）,血清ALT、AST水平、组胺含量、肝LDH活性、MDA、TNF-α、IL-8水平升高,SOD活性减弱（P<0.05）。与IR组相比,IR+C和IR+K组肝脏损伤减轻,以上指标呈相反趋势（P<0.05）,IR+CP组则加重肝损伤及恶化检测结果（P<0.05）。结论：再灌注前抑制肥大细胞功能可以减轻肠缺血再灌注后早期肝脏损伤,其机制可能与组胺释放、氧化损伤和炎症反应有关。     

Carbon monoxide inhalation protects rat intestinal grafts from ischemia/reperfusion injury

Carbon monoxide (CO), a byproduct of heme catalysis by heme oxygenases, has been shown to exert anti-inflammatory effects. This study examines the cytoprotective efficacy of inhaled CO during intestinal cold ischemia/reperfusion injury associated with small intestinal transplantation. Orthotopic syngenic intestinal transplantation was performed in Lewis rats after 6 hours of cold preservation in University of Wisconsin solution. Three groups were examined: normal untreated controls, control intestinal transplant recipients kept in room air, and recipients exposed to CO (250 ppm) for 1 hour before and 24 hours after surgery. In air grafts, mRNA levels for interleukin-6, cyclooxygenase-2, intracellular adhesion molecule (ICAM-1), and inducible nitric oxide synthase rapidly increased after intestinal transplant. Histopathological analysis revealed severe mucosal erosion, villous congestion, and inflammatory infiltrates. CO effectively blocked an early up-regulation of these mediators, showed less severe histopathological changes, and resulted in significantly improved animal survival of 92% from 58% in air-treated controls. CO also significantly reduced mRNA for proapoptotic Bax, while it up-regulated anti-apoptotic Bcl-2. These changes in CO-treated grafts correlated with well-preserved CD31(+) vascular endothelial cells, less frequent apoptosis/necrosis in intestinal epithelial and capillary endothelial cells, and improved graft tissue blood circulation. Protective effects of CO in this study were mediated via soluble guanylyl cyclase, because 1H-(1,2,4)oxadiazole (4,3-alpha) quinoxaline-1-one (soluble guanylyl cyclase inhibitor) completely reversed the beneficial effect conferred by CO. Perioperative CO inhalation at a low concentration resulted in protection against ischemia/reperfusion injury to intestinal grafts with prolonged cold preservation.     

Temporal relationship of serum markers and tissue damage during acute intestinal ischemia/reperfusion

OBJECTIVE:

It is essential to identify a serological marker of injury in order to study the pathophysiology of intestinal ischemia reperfusion. In this work, we studied the evolution of several serological markers after intestinal ischemia reperfusion injury in rats. The markers of non-specific cell damage were aspartate aminotransferase, alanine aminotransaminase, and lactic dehydrogenase, the markers of inflammation were tumor necrosis factor alpha, interleukin-6, and interleukin-1 beta, and the markers of intestinal mucosal damage were intestinal fatty acid binding protein and D-lactate. We used Chiús classification to grade the histopathological damage.

METHODS:

We studied 35 Wistar rats divided into groups according to reperfusion time. The superior mesenteric artery was clamped for 30 minutes, and blood and biopsies were collected at 1, 3, 6, 12, 24, and 48 hours after reperfusion. We plotted the mean ± standard deviation and compared the baseline and maximum values for each marker using Student''s t-test.

RESULTS:

The maximum values of interleukin-1 beta and lactic dehydrogenase were present before the maximal histopathological damage. The maximum tumor necrosis factor alpha and D-lactate expressions coincided with histopathological damage. Alanine aminotransaminase and aspartate aminotransferase had a maximum expression level that increased following the histopathological damage. The maximum expressions of interluken-6 and intestinal fatty acid binding protein were not significantly different from the Sham treated group.

CONCLUSION:

For the evaluation of injury secondary to acute intestinal ischemia reperfusion with a 30 minute ischemia period, we recommend performing histopathological grading, quantification of D-lactate, which is synthesized by intestinal bacteria and is considered an indicator of mucosal injury, and quantification of tumor necrosis factor alpha as indicators of acute inflammation three hours after reperfusion.     

萎缩小肠粘膜上皮细胞凋亡及增殖细胞核抗原表达变化的研究

目的：探讨小肠粘膜萎缩的发生机制。材料和方法;采用原位末端标记和免疫组化的方法,对正常和萎缩肠粘膜上皮细胞凋亡的发生,分布及增殖细胞核抗原（ＰＣＮＡ０的表达进行对比研究。结果：调亡细胞主要位于肠绒毛的顶部,萎缩小肠粘膜上皮细胞凋亡的发生率明显高于正常小肠（Ｐ〈０．０５）;而ＰＣＮＡ阳性表达细胞主要位于腺隐窝区,萎缩小肠粘膜上皮细胞ＰＣＮＡ的阳性计数较正常小肠显著降低。     

Morphologic, biochemical, and molecular evidence of apoptosis during the reperfusion phase after brief periods of renal ischemia.

A multiparametric analysis to demonstrate that even brief periods of arterial clamping can initiate extensive cell loss in a rat kidney through the process of apoptosis during the 48-hour period after reperfusion was performed. Microscopic examination of rat renal tissues subject to a 5-, 30-, or 45-minute period of complete ischemia showed the presence of apoptotic bodies both within and occasionally between renal tubules, appearing as early 12 hours after reperfusion, and increasing in numbers at 24 hours. Furthermore, DNA extracted from such reperfused renal tissue demonstrated the appearance of a distinct "ladder" pattern of DNA fragments after electrophoresis in agarose gels, a phenomenon commonly associated with cells undergoing apoptosis and in contrast to the predominant smear pattern obtained after electrophoresis of DNA extracted from necrotic renal tissue. Finally, messenger RNA (mRNA) encoding sulfated glycoprotein-2, a gene product previously identified to apoptotic renal cells, was found to be highly expressed in the 30-minute arterial clamped rat kidney after 24 hours of reperfusion, but was not detectable in mRNA extracted from renal tissue after 24 hours chronic infarction. This study demonstrates that a combination of morphologic, biochemical, and molecular markers can be used to distinguish predominant modes of cell death in varying forms of tissue injury. Application of these analytical techniques to renal vascular injury has distinguished that brief periods of complete ischemia initiates a form of cell death (apoptosis) during a subsequent reperfusion phase that is drastically different from cellular necrosis induced by prolonged severe ischemia.     

外周血白细胞凋亡障碍与大鼠肠缺血-再灌注损伤的关系

目的： 探讨外周血白细胞和中性粒细胞凋亡障碍在肠缺血-再灌注（IR）损伤中的作用。方法：20只雄性SD大鼠随机分为肠IR组和假手术对照组,每组10只。肠IR组夹闭肠系膜上动脉（SMA）30 min后再灌注60 min;对照组只分离而不夹闭SMA。观察肠黏膜形态学变化;检测肠黏膜上皮细胞凋亡指数（TUNEL法）和caspase-3活性;Annexin-V/PI法检测外周血白细胞和中性粒细胞（PMN）凋亡比例;检测夹闭前、夹闭30 min、再灌注30 min、再灌注60 min外周血白细胞数量。结果：(1)光镜下,对照组未见肠黏膜损伤,而IR组肠黏膜损伤严重;（2）IR组肠黏膜上皮细胞凋亡指数和caspase-3活性比对照组明显增高（P<0.05）;（3）IR组外周血白细胞和PMN凋亡比例比对照组明显降低（P<0.05）;IR组外周血白细胞数量在缺血30min时明显增高,再灌注后进一步增高,与缺血前和对照组比都有显著差异（P<0.05）。(4)肠黏膜caspase-3活性与外周血白细胞凋亡比例有显著的负相关（r=-0.764, P<0.01）,与PMN凋亡比例也有显著的负相关（r=-0.845,P<0.01）;肠黏膜上皮细胞凋亡指数与PMN凋亡比例也有显著的负相关（r=-0.638, P<0.05）。结论：外周血白细胞数量增加及凋亡障碍与缺血-再灌注引起的肠黏膜细胞损伤密切相关。     

人硫氧还蛋白对肺缺血再灌注损伤时细胞凋亡及Bcl-2/Bax的影响

目的:探讨细胞凋亡与肺缺血再灌注损伤的关系以及人硫氧还蛋白对凋亡及其相关基因的影响。方法:健康清洁级Wistar大鼠84只,随机分为对照组、肺缺血再灌注1h、3h、5h组和人硫氧还蛋白干预1h、3h和5h组。复制肺缺血再灌注损伤模型。采用电子显微镜和原位缺口末端标记法观测肺组织细胞凋亡的变化和凋亡指数,免疫组化技术检测肺组织细胞Bcl-2、Bax及凋亡信号调节激酶1(ASK1)蛋白表达的变化。结果:肺缺血再灌注组肺组织细胞凋亡指数、ASK1、Bcl-2和Bax蛋白表达均显著高于对照组(均P0.01),超微结构呈严重损伤性改变。人硫氧还蛋白干预组ASK1、Bax的表达显著下降(均P0.01),Bcl-2的表达及Bcl-2/Bax比值显著上调(P0.05或P0.01),肺组织细胞凋亡指数也显著低于缺血再灌注组(P0.01)。肺组织细胞凋亡指数分别与ASK1、Bax蛋白之间均呈显著正相关(分别r=0.775、r=0.814;均P0.01);与Bcl-2/Bax蛋白呈显著负相关关系(r=-0.275,P0.05)。结论:Bcl-2/Bax比值下调启动的肺组织细胞凋亡可能参与了肺缺血再灌注损伤的发生。人硫氧还蛋白可能通过下调ASK1的表达,提高Bcl-2/Bax的比值减少肺组织细胞凋亡,从而减轻肺缺血再灌注损伤。     

三七总皂甙对肺缺血再灌注损伤时细胞凋亡及Fas/FasL的影响

目的：探讨细胞凋亡与肺缺血再灌注损伤的关系以及三七总皂甙的作用及机制。 方法: 健康日本大耳白兔84只，随机分为对照组、肺缺血再灌注1、3、5 h组和三七总皂甙干预1、3和5 h组。复制肺缺血再灌注损伤模型。采用原位缺口末端标记（TUNEL）法观测肺组织细胞凋亡指数，免疫组化和原位杂交技术检测肺组织细胞Fas/FasL系统蛋白和基因表达的变化。 结果: 肺缺血再灌注组肺组织细胞凋亡指数和Fas/FasL蛋白及基因表达均显著高于对照组（均P<0.01）。三七总皂甙干预组Fas/FasL mRNA及其蛋白质的表达显著低于缺血再灌注组（P<0.01），肺组织细胞凋亡指数也显著低于缺血再灌注组（P<0.01）。肺组织细胞凋亡指数分别与Fas/FasL蛋白和Fas/FasL mRNA之间均呈显著正相关（r分别=0.540,0.658,0.668,0.686;均P<0.01）。 结论: Fas/FasL系统活化启动的肺组织细胞凋亡可能参与了肺缺血再灌注损伤的发生。三七总皂甙可能通过抑制Fas/FasL系统的激活，阻遏肺组织细胞凋亡，从而减轻肺缺血再灌注损伤。     

The pathogenesis of and susceptibility to malabsorption syndrome in broilers is associated with heterophil influx into the intestinal mucosa and epithelial apoptosis.

Malabsorption syndrome (MAS) in broilers is characterized by enteritis and reduced body weight gain. The pathogenesis of the intestinal lesions and the reasons for susceptibility differences between broiler lines are not clear. We studied the development of enteric lesions, epithelial apoptosis, and cell proliferation in relation to susceptibility. One-day-old chickens from two broiler lines were orally inoculated with intestinal homogenate derived from MAS-affected chickens. Vacuolar degeneration and apoptosis of the villous epithelium and infiltration of heterophils into the lamina propria occurred from day 1 post-inoculation. Following heterophil accumulation, at day 4 to 6 post-inoculation, there was severe apoptosis of the crypt epithelium and villous atrophy. The susceptible broilers had a significantly greater influx of heterophils and, subsequently, severe epithelial apoptosis and cystic damage to the crypts. There appeared to be a causal relationship between heterophil influx and the onset of apoptosis. Coincident with the epithelial apoptosis, MAS-affected chickens had crypt hyperproliferation and faster epithelial turnover. Heterophil infiltration and epithelial apoptosis appear to be critical in the pathogenesis of MAS. Heterophil recruitment may be a major factor in differences in susceptibility to MAS.     

乳果糖预处理减轻大鼠肠缺血再灌注损伤的机制研究

 目的： 探讨乳果糖预处理对大鼠肠缺血再灌注损伤的影响及其作用机制。方法： 随机将30只SD大鼠分成假手术组、缺血再灌注组和乳果糖预处理组。乳果糖预处理组在手术前7 d每天给予乳果糖灌胃,假手术组和缺血再灌注组在手术前7 d每天给予等量生理盐水灌胃。手术分离肠系膜上动脉,通过夹闭30 min、再灌注60 min诱导缺血再灌注损伤。收集血清检测白细胞介素6（IL-6）、肿瘤坏死因子α(TNF-α)和IL-1β水平。HE染色用来评估组织的损伤程度,TUNEL检测小肠上皮细胞的凋亡。部分小肠组织用来检测丙二醛、超氧化物歧化酶及激活型caspase-3的表达水平。结果： 乳果糖预处理显著减轻缺血再灌注引起的肠组织损伤和小肠上皮细胞凋亡,并显著抑制血清中细胞因子的水平和肠组织的脂质过氧化。结论： 乳果糖预处理可能通过抑制细胞凋亡和脂质过氧化减轻缺血再灌注引起的肠道损伤。