Heart ischaemia-reperfusion process in adjuvant arthritic rats

Inflammation Research -     

Macrophages from adjuvant arthritic rats preferentially synthetize prostacyclin

Peritoneal macrophages obtained from rats 21 days after induction of adjuvant arthritis and maintained in culture for 20 h in presence of [¹⁴C]-arachidonic acid and 10% foetal calf serum were found to have increased capacity for synthetizing prostacyclin and diminished capacity for synthetizing PGE₂ compared with macrophages from normal rats.Similar results were obtained when foetal calf serum was replaced by either normal or arthritic rat serum. Orally administered indomethacin inhibited the increased synthesis of prostacyclin.     

Collagenase and elastase in the serum of adjuvant arthritic rats

Collagenase and elastase activities in the serum of adjuvant arthritic rats declined with time as the disease progressed and did not parallel increases in alpha₁-macroglobulin or alpha₂-acute phase globulin levels. The fall in collagenase and elastase activities was accompanied by a decline in serum alpha₁-proteinase inhibitor levels. It was concluded that the fall in collagenase and elastase activities in serum was due to inactivation by serum anti-proteases.     

Effect of pentoxifylline on single red cell deformability

Summary In the present investigation the effect of pentoxifylline on single red cell deformability was determined. The deformability of human red blood cells were measured in a Singlepore Erythrocytes Rigidometer (SER). The new method determines optoelectronically the passage of each individual cell through a singlepore membrane (6 µm diameter and 50 µm length) under a driving pressure gradient (p=100 Pa, =3 Pa). Venous human blood samples were taken, prepared and divided into three samples. Sample A served as a physiological control, while to sample B and C CaCl₂-solution was added. After Ca²⁺ stress sample C was incubated with 0.36 mmol/l pentoxifylline¹. The medium passage time (MPT) for sample A was 43.3 ± 6.5 ms and for sample B 87.5 ± 14.7 ms. The addition of pentoxifylline to the Ca²⁺-treated red cell suspension (sample C) reduced the MPT to 51.6 ± 11.3 ms.     

Improved filtration method for red cell deformability measurement

A method which enables reliable measurements of red cell deformability in whole blood to be performed is presented. It is based on the Nuclepore filtration method described byReid et al. (1976). Its reliability was much improved, obtaining an accuracy of within 5% by a technique to remove air bubbles trapped in the filter pores, which caused the poor reproducibility observed before. Simple analyses of the flow characteristics of whole blood and the haematocrit dependence of whole blood passage time were given to eliminate the effect of transient pore blockings of white cells and the contribution of different haematocrit in the whole blood passage time. A mean pore passage time of single red cells is obtainable as a quantitative index of red cell deformability. Furthermore, a good utilisation was achieved by making full use of electrically operated valves and aspiration pumps. It is possible to repeat measurements at intervals of 3 min. This improved filtration method will be useful for diagnostic purposes since it can avoid artefacts caused by artificial treatments added on blood samples and time changes after blood sampling.     

Chronic inflammation in adjuvant arthritic rats correlates with enhancement of 12-l-HETE-synthesis

The development of chronic inflammation in adjuvant arthritic rats was found to be strongly correlated with the appearance in serum of a factor (HSF) which enhanced the formation of 12-l-HETE by platelet-lipoxygenase, and with the serum-concentration of 12-l-HETE. The latter was determined by scanning at 235 nm after extraction and high performance thin-layer chromatography. Arthritic rat platelet-rich plasma (PRP) converted exogenous arachidonic acid to 12-l-HETE at a rate 2.6-fold higher than control rat PRP. By resuspending arthritic rat platelets in normal rat plasma, and normal rat platelets in arthritic rat plasma, this increase in conversion rate was found to be caused by HSF present in the arthritic rat plasma. Treatment of arthritis with non-steroidal anti-inflammatory drugs inhibited HSF activity as well as the increase in serum-12-l-HETE concentration, which indicates a prostaglandin-mediated mechanism of HSF synthesis or release.     

Possible role of red cell deformability and microvasculature in microcirculation.

The roles of the deformability of red blood cells (RBC) and the microvasculature in the maintenance of blood flow were investigated in terms of the pressure (P)-flow rate (Q) relationships in human RBC suspension perfusions of bullfrog hind limb. Although isotonicity for the bullfrog is approximately 215 mOsm/kgH2O, perfusions in intact hind limbs showed no change in the P-Q relationship at test solution osmolalities ranging from approximately 150 to approximately 300 mOsm/kgH2O. The deformability of RBC was examined in glutaraldehyde-fixed hind limbs. Perfusion of fixed limbs with RBC suspension revealed minimum resistance to flow at osmolalities of approximately 250 to approximately 420 mOsm/kgH2O, whereas the same experiment in intact limbs revealed minimum flow resistance at osmolalities of approximately 200 to approximately 300 mOsm/kgH2O. It was noteworthy that the reduction of RBC deformability was not observed in intact limbs at osmolalities of approximately 250 to approximately 200 mOsm/kgH2O. Heinz body-forming RBC from a patient with unstable hemoglobin (Hb) disease (Hb Yokohama) exhibited a marked reduction in deformability as compared with normal RBC in fixed limbs, while there was no discernible difference between the two types of RBC in intact limbs, thereby suggesting that the microvascular bed can compensate, to an appreciable extent, for the impaired deformability of RBC, probably via its distensibility and/or a wall effect. The present study has considerable implications concerning the link between in vitro experiments and the in vivo situation, including the hemodynamic characteristics of RBC suspensions such as the effective viscosity.     

Time-dependent reaction of human red cell deformability on sphering agents

Summary The increase of fractional excretion of sodium following the infusion of isotonic saline solution is quantitatively the same in dog kidneys perfused by a whole animal or by a pump-oxygenator machine at identical arterial and venous pressures. The equal response found in both experimental conditions demonstrates that the dilution of the blood, and primarily the decrease of post-glomerular plasma oncotic pressure, represents the only extrarenal humoral factor of significant importance in the reduction of fractional reabsorption of sodium following large saline infusion. The renal response to hemodilution is reduced similarly in both types of experiments when the dogs have been previously submitted to a dietary deprivation of sodium. The decreased sensitivity of the kidney to the stimulus of hemodilution appears as a major determinant of the poor natriuretic response to saline loading of sodium-deprived animals.This work has been performed with the help of the Fonds National de la Recherche Scientifique of Belgium.     

Differential effects of anti-arthritic agents on subnormal plasma iron levels in adjuvant arthritic rats

Nonsteroidal anti-inflammatory drugs (NSAID's) and other antirheumatic compounds such as disease modifying antirheumatic drugs (DMARD's), immunosuppressives and glucocorticoids were tested to determine if daily medication for two weeks could elevate subnormal levels of plasma iron in adjuvantarthritic (AA) rats. Aspirin, indomethacin, ibuprofen and phenylbutazone were chosen as representative carboxylic acids and pyrazole NSAID's. Although NSAID's at all doses significantly reduced non-injected paw swelling, no NSAID significantly enhanced subnormal plasma iron levels in AA rats. In contrast, the standard DMARD's auranofin and gold sodium thiomalate, as well as the glucocorticoid, dexamethasone and the imunosuppressives, methotrexate andcyclosporin-A all significantly restored plasma iron levels 28 to 100 percent. Plasma iron depression, a parameter of the acute phase response probably under regulation by pro-inflammatory cytokines, is not reversed by NSAID treatment. This appears to be a useful method for distinguishing NSAID's from other anti-arthritic compounds.     

Lymphocyte activating factor (LAF) and the acute-phase response in adjuvant arthritic rats

The purpose of the study was to determine the temporal relationship between lymphocyte activating factor (LAF) activity and the acute-phase response, as measured by plasma fibronectin (Fn), C-reactive protein (CRP), and albumin levels in adjuvant arthritic rats. LAF activity as measured in the thymocyte costimulator assay, and plasma Fn, CRP, and albumin levels were measured during the acute (Day 3), intermediate (Day 10), and systemic (Day 17) phases of arthritic disease. On Day 3, supernatants from whole spleen cells of adjuvant-injected rats did not exhibit abnormal LAF activity. By Day 10, LAF activity in splenic supernatants from arthritics was significantly (P less than or equal to 0.05) higher than normal, although the increase was no greater than 60%. On Day 17 the LAF activity from arthritic rats had increased an average 300% compared to normals. In contrast to the time course of IL-1 activity, Fn and CRP levels in the arthritic rat were significantly higher than normal at all three time points, although there was a transient fall in Fn and CRP concentrations on Day 10. Plasma albumin levels in arthritic rats were subnormal (P less than or equal to 0.01) on Days 3, 10, and 17, although the concentration of plasma albumin on Day 10 was significantly higher than that measured on Day 3. The acute, intermediate, and systemic phases of adjuvant arthritic paw inflammation paralleled the abnormal profile of Fn, CRP, and albumin concentrations over time. However, LAF activity from arthritic rat spleen cells increased gradually and more closely coincided with the systemic appearance of the disease. Since the appearance of abnormal plasma protein levels in arthritic rats preceded the appearance of increased splenic LAF activity, it appears that there is no causal relationship between enhanced splenic LAF activity and early alteration of plasma Fn, CRP, and albumin levels.     

Alteration of interleukin-1 activity and the acute phase response in adjuvant arthritic rats treated with disease modifying antirheumatic drugs

Interleukin-1 (IL-1) activity and the acute phase response, as measured by plasma CRP and iron, were used to determine if the standard disease modifying antirheumatic drugs (DMARDs), gold, chloroquine andd-penicillamine had a common profile of activity in the adjuvant arthritic (AA) rat. All drugs were tested at a dose which significantly reduced noninjected paw swelling in AA rats. Inhibition of paw edema ranged from 37% ford-penicillamine (100 mg/kg) to 69% for auranofin (10 mg/kg). Two week medication of AA rats with gold sodium thiomalate (GST, 10 mg/kg, i.m.) or auranofin (10 mg/kg, p.o.) resulted in a significant decrease in splenic IL-1 activity, as measured in the standard lymphocyte activating factor (LAF) assay. The acute phase response, often associated with elevated IL-1 activity, was also significantly reduced following treatment of AA rats with 10 mg/kg of GST or auranofin (oral gold). Inhibition of the acute phase response by gold was determined by a significant reduction of plasma CRP levels (56–71% reduction) and enhancement of plasma iron levels (27–52% enhancement).In contrast to the effect of GST and auranofin on IL-1, CRP and iron, treatment with chloroquine (20, 30 and 35 mg/kg) andd-penicillamine (55 and 100 mg/kg) failed to reduce the acute phase response (as measured by plasma CRP and iron) or alter LAF activity from AA rat spleen cell supernatants. Based on its ability to reduce LAF activity in spleen cell supernatants and reduce the acute phase response, it is possible that the activity of gold in the AA rat may in part be due to its ability to inhibit IL-1 productionin vivo. The inability of chloroquine andd-penicillamine to alter LAF activity and the acute phase response in AA rats does not preclude their possession of an immunoregulatory mechanism of action, but it does indicate that their mechanism of action in the AA rat probably differs from that of GST and auranofin.     

Anti-inflammatory and anti-oxidant properties of Sida rhombifolia stems and roots in adjuvant induced arthritic rats

Free radical stress leads to tissue injury and progression of disease conditions such as arthritis, hemorrhagic shock, atherosclerosis, diabetes, hepatic injury, aging and ischemia, reperfusion injury of many tissues, gastritis, tumor promotion, neurodegenerative diseases and carcinogenesis. Safer anti-oxidants suitable for long term use are needed to prevent or stop the progression of free radical mediated disorders. Herbal medicine provides a foundation for various traditional medicine systems worldwide. The Sida species is one of the most important families of medicinal plants in India. Hence, the present study was aimed to investigate the possible anti-oxidant potential of Sida rhombifolia extracts for 30 days on adjuvant induced arthritis in experimental rats. The altered levels of hematological parameters were reverted to near normal levels, especially the elevated rate of erythrocyte sedimentation was significantly reduced by S. rhombifolia extracts in experimental rats. Oral administration of root and stem of S. rhombifolia extracts significantly increased the levels of thiobarbituric acid reactive substances and activities of catalase and glutathione peroxidase and decreased the levels of reduced glutathione and superoxide dismutase activity in arthritis induced rats. The free radical scavenging activity of the plant was further evidenced by histological and transmission electron microscopy observations made on the hind limb tissue.     

Anti-inflammatory and anti-oxidant properties of Sida rhombifolia stems and roots in adjuvant induced arthritic rats

Free radical stress leads to tissue injury and progression of disease conditions such as arthritis, hemorrhagic shock, atherosclerosis, diabetes, hepatic injury, aging and ischemia, reperfusion injury of many tissues, gastritis, tumor promotion, neurodegenerative diseases and carcinogenesis. Safer anti-oxidants suitable for long term use are needed to prevent or stop the progression of free radical mediated disorders. Herbal medicine provides a foundation for various traditional medicine systems worldwide. The Sida species is one of the most important families of medicinal plants in India. Hence, the present study was aimed to investigate the possible anti-oxidant potential of Sida rhombifolia extracts for 30 days on adjuvant induced arthritis in experimental rats. The altered levels of hematological parameters were reverted to near normal levels, especially the elevated rate of erythrocyte sedimentation was significantly reduced by S. rhombifolia extracts in experimental rats. Oral administration of root and stem of S. rhombifolia extracts significantly increased the levels of thiobarbituric acid reactive substances and activities of catalase and glutathione peroxidase and decreased the levels of reduced glutathione and superoxide dismutase activity in arthritis induced rats. The free radical scavenging activity of the plant was further evidenced by histological and transmission electron microscopy observations made on the hind limb tissue.     

Excitatory amino acid release in the locus coeruleus during naloxone-precipitated morphine withdrawal in adjuvant arthritic rats

OBJECTIVE AND DESIGN: Excitatory amino acid levels in the locus coeruleus (LC) and the behavioral signs during naloxone-precipitated withdrawal in arthritic rats treated with chronic morphine were investigated by in vivo microdialysis. METHODS: Increases in glutamate (Glu) and aspartate (Asp) were noted after naloxone (48 nmol/5 microl, LC)-precipitated withdrawal from normal and adjuvant arthritic rats which had been intracerebroventricularly infused for 3 days with morphine (26 nmol/l microl/h). RESULTS: The increases in Glu and Asp levels on morphine withdrawal in normal rats were attenuated following naloxone challenge in the morphine-dependent arthritic rats. Moreover, behavioral signs during morphine withdrawal were detected following the naloxone challenge in both the morphine-dependent normal and adjuvant arthritic rats, but not in the saline-infused controls. CONCLUSIONS: These results show that the attenuation of Glu and Asp release from the LC in the adjuvant arthritic rats might explain the anti-inflammatory and analgesic effects of mu-opioids in adjuvant arthritic rats.     

Drug actions on delayed-type hypersensitivity in rats with developing and established adjuvant arthritis

Rats were sensitized by i. d. injection in the base of the tail with Freund's complete adjuvant (FCA) and were challenged i. d. in the dorsal skin with mycobacterial antigen. The 24 hour dermal delayed-type hypersensitivity (DTH) response increased up to 10 days after FCA injection followed by a decrease by day 15 which coincided with the development of adjuvant arthritis (AA). Drug studies were performed, using a 4-day dosing schedule, on optimal DTH elicited on day 10, suboptimal DTH elicited on day 15, and AA (day 16). Cyclosporine, leflunomide and prednisolone significantly inhibited day 10 DTH and AA with no effect on day 15 DTH. Indomethacin and tiaprofenic acid significantly inhibited AA with no effect on either DTH response. Chloroquine, levamisole,d-penicillamine, diazepam and RU38468 had no significant effect on DTH or AA. These findings suggest a complex temporal relationship between AA, DTH and drug actions.     

Extensional flow-based assessment of red blood cell deformability using hyperbolic converging microchannel

The deformability of the red blood cell (RBC), is known to be closely related to microcirculation and diagnosis of specific diseases such as malaria, arterial sclerosis, sepsis, and so on. From the viewpoint of the flow type, conventional methods to measure the cell deformability have exploited simple shear or complex flow field with little focus on extensional flow field. In this paper, we present a new approach to assess cell deformability under the extensional flow field. For this purpose, a hyperbolic converging microchannel was designed, and the cell deformation in the extensional flow region was continuously monitored. It overcomes the limitation of conventional methods by reducing experiment time. As quantified by the degree of deformation, the extensional flow (Deformation Index = 0.51 at 3.0 Pa) was found to be more efficient in inducing cell deformation compared to the shear flow (Deformation Index = 0.29 at 3.0 Pa). This indicates the insufficiency of the existing models that predict the blood damage in artificial organs, which only consider shear flow. Also, this method could detect the heat-induced difference in deformability of RBCs. It provides a new platform to study the clinical effect of RBC deformability under extensional flow, and is expected to contribute the association of several diseases and deformability of RBCs.     

急性心肌缺血时红细胞变形性的变化及其机理

本实验观察了犬急性心肌缺血时体循环血与缺血区局部静脉血中红细胞变形性（ＲＣＤ）的变化。结果表明，阻断冠脉血流后高切变率下全血粘度（ηｂｈ）和红细胞刚性指数（ＥＲＩ）明显增高，而缺血区局部血液中此二者的变化明显大于体循环静脉血。事先切断内脏大神经，可使阻断冠脉后体循环血（而不是局部静脉血）的ηｂｈ和ＥＲＩ变化基本消失。缺血区局部血液ｐｈ和ｐＯ２明显降低，ｐＣＯ２明显增高，红细胞内ＡＴＰ含量减少和钙含     

An assessment of red cell deformability using a simple filtration method.

We assessed the simple method of measuring red cell deformability described by Reid et al. The technique was found to be reproducible. The validity of the method as a measure of red cell deformation was confirmed by (a) marked reduction of the deformability index after fixation of red cells with glutaraldehyde, and (b) an inverse correlation of deformability index with high-shear blood viscosity (r = 0.4; P < 0.001). There was no correlation of deformability index with low-shear blood viscosity, plasma viscosity, fibrinogen, or the white cell count. In normal subjects, deformability index was similar in males and females, and in smokers and non-smokers. Patients with acute myocardial infarction, or intermittent claudication, had reduced deformability compared to controls (P < 0.01).