间斑寇蛛坏死毒素致大鼠急性肾损伤的病理改变

目的 以间斑寇蛛毒素致急性肾损伤的实验大鼠为模型,从病理角度研究不同剂量的蛛毒致大鼠肾损伤的程度。方法 采集蛛毒粗毒后注射到大鼠体内,每小时观察中毒反应,24 h后观察肾功能变化,处死后进行肾脏组织病理学实验。结果 蛛毒剂量达到10 ug/kg时,实验大鼠即产生了明显的神经毒反应,随着蛛毒剂量的增加实验大鼠肾脏逐渐表现出肾小囊及肾小管间质出血、水肿、肾小球坏死、肾小管内皮细胞呈空泡样变性、肾皮质部呈玻璃样改变、肾髓质部无完整的肾小球结构及玻璃样改变的连续病变特征;然而肾功能各项指标如尿素氮、尿酸、肌酐及电解质钾、钠、钙、氯也无变化(P>0.05),但各剂量蛛毒组的尿蛋白均显著升高(3+)(P <0.01)。结论 新疆间斑寇蛛的蜘蛛坏死毒素,较小剂量就可使大鼠表现出尿蛋白的大量升高,这与肾组织的病理性坏死直接相关,虽未表现出肾衰的特征,可能是与急性期的相关指标未来得及变化有关。

Role of LPS/CD14/TLR4-mediated inflammation in necrotizing enterocolitis:Pathogenesis and therapeutic implications

AIM:To establish the roles of lipopolysaccharide (LPS)/CD14/toll-like receptor 4 (TLR4)-mediated inflammation in a rat model of human necrotizing enterocolitis (NEC).METHODS: Six pairs of intestinal samples from human NEC were collected before and after recovery for histological and molecular analysis of inflammatory cytokines and signaling components. In the rat NEC model, we isolated 10-cm jejunum segments and divided them into six groups (n=6) for sham operation, treatment with LPS, bowel distension, combined bowel distension and LPS stimulation, and two therapeutic groups. The potential eff icacy of a recombinant CD18 peptide and a monoclonal CD14 antibody was evaluated in the latter two groups. The serum and tissue levels of several inflammatory mediators were quantified by real-time polymerase chain reaction, ELISA and immunoblotting.RESULTS: Human acute phase NEC tissues displayed significant increases (P<0.05) in levels of TLR4, CD14, myeloid differentiation protein (MD)-2, tumor necrosis factor (TNF)-α and nuclear factor-κB when compared to those after recovery. The histological and inflammatory picture of human NEC was reproduced in rats that were treated with combined bowel distension and LPS, but not in the sham-operated and other control rats. Serum levels of interleukin-6 and TNF-α were also elevated. The NEC pathology was attenuated by treating the NEC rats with a monoclonal CD14 antibody or an LPS-neutralizing peptide.CONCLUSION:LPS and distension are required to produce the histological and inflammatory features of NEC. A potential treatment option is blocking LPS activation and leukocyte infi ltration.

Preventive effect of tetramethylpyrazine on intestinal mucosal injury in rats with acute necrotizing pancreatitis

AIM： To evaluate the role of microcirculatory disorder （MCD） and the therapeutic effectiveness ;of tetramethylpyrazine （TMP） on intestinal mucosa injury in rats with acute necrotizing pancreatitis （ANP）.METHODS： A total of 192 Sprague-Dawley rats were randomly divided into three groups： normal control group （C group）, ANP group not treated with TMP （P group）, ANP group treated with TMP （T group）. An ANP model was induced by injection of 50 g/L sodium taurocholate under the pancreatic membrane （4 mL/kg）. C group received isovolumetric injection of 9 g/L physiological saline solution using the same method. T group received injection of TMP （10 mL/kg） via portal vein. Radioactive biomicrosphere technique was used to measure the blood flow at 0.5, 2, 6 and 12 h after the induction of ANP. Samples of pancreas, distal ileum were collected to observe pathological changes using a validated histology score. Intestinal tissues were also used for examination of myeloperoxidase （MPO） expressed intraceUularly in azurophilic granules of neutrophils.RESULTS： The blood flow was significantly lower in P group than in C group （P 〈 0.01）. The pathological changes were aggravated significantly in P group. The longer the time, the severer the pathological changes. The intestinal MPO activities were significantly higher in P group than in C group （P 〈 0.01）. The blood flow of intestine was significantly higher in T group than in P group after 2 h （P 〈 0.01）. The pathological changes were alleviated significantly in T group. MPO activities were significantly lower in T group than in P group （P 〈 0.01 or P 〈 0.05）. There was a negative correlation between intestinal blood flow and MPO activity （r = -0.981, P 〈 0.01） as well as between intestinal blood flow and pathologic scores （r = -0.922, P 〈 0.05）.CONCLUSION： MCD is an important factor for intestinal injury in ANP. TMP can ameliorate the condition of MCD and the damage to pancreas and intestine.

Nuclear factor-kappaB activation on the reactive oxygen species in acute necrotizing pancreatitic rats

AIM： To investigate the potential role of nuclear factor kappa-B （NF-κB） activation on the reactive oxygen species in rat acute necrotizing pancreatitis （ANP） and to assess the effect of pyrrolidine dithiocarbamate （PDTC, an inhibitor of NF-κB）.METHODS： Rat ANP model was established by retrograde injection of 5% sodium taurocholate into biliopancreatic duct. Rats were randomly assigned to three groups （10 rats each）： Control group, ANP group and PDTC group. At the 6^th of the model, the changes of the serum amylase,nitric oxide （NO）, malondialdehyde （MDA）, superoxide dismutase （SOD） and pancreatic morphological damage were observed. The expressions of inducible nitric oxide （iNOS） were observed by SP immunohistochemistry. And bhe expressions of NF-κB p65 subunit mRNA were observed by hybridization in situ.RESULTS： Serum amylase and NO level decreased significantly in ANP group as compared with PDTC administrated group [（7 170.40＋1 308.63） U/L vs（4 074.10＋1 719.78） U/L,P〈0.05], [（76.95±9.04） μmol/L vs （65.18±9.02） μmol/L,P〈0.05] respectively. MDA in both ANP and PDTC group rose significantly over that in control group [（9.88＋1.52）nmol/L, （8.60±1.41） nmol/L, vs （6.04：hl.78） nmol/L,P〈0.05], while there was no significant difference between them. SOD levels in both ANP and PDTC group underwent a significant decrease as compared with that in control[（3 214.59±297.74） NU/mL, （3 260.62±229.44） NU/mL,vs（3 977.80＋309.09） NU/mL, P〈0.05], but there was no significant difference between them. Though they were still higher bhan those in Control group, pancreas destruction was slighter in PDTC group, iNOS expression and NF-κB p65 subunit mRNA expression were lower in PDTC group as compared with ANP group.CONCLUSION： We conclude that correlation among NF-κB activation, serum amylase, reactive oxygen species level and tissue damage suggests a key role of NF-κB in the pathogenesis of ANP. Inhibition of NF-κB activation may reverse the pancreatic damage of rat ANP and the production of reactive oxygen species.

Toxicity of Alum to Newzealand Rabbits

This study was considered to assess the risk of alum which is used in Sudan for drinking water treatment purposes for a long period without toxicity freedom records .Newzealand rabbits were chosen for animal phase trials, divided into 3 groups. One group was the undosed controls. Test groups were given alum at dose rates of 1% and 20% respectively for two groups after an adaptation period. Clinical signs were observed together with postmortem and histopathological examinations. Chemical investigations included enzymatic, metabolic, electrolyte and hematological changes. The test rabbits demonstrated low voice, inappitence, whitish salivation, watery diarrhea and recumbence followed by emphysematous, lungs, electrolyte imbalance, renal dysfunctions, stiff focal inflammation of the empty intestines and congested liver with white spots. The control group was normal .On atomic absorption only the lungs kept residual alum, while the livers washed- out the substance ,may be via bile .Alum -dosed rabbits showed necrosis in the cortex and medulla of the kidney, emphysema in the lungs and necrosis in the hepatocytes. On evaluation of the above results, alum was considered to be toxic to Newzealand rabbits at dose rates tried.