Lung injury after aortic occlusion-reperfusion in rats: the role of gadolinium chloride

Depletion of pulmonary intravascular macrophages rescues inflammation-induced delayed neutrophil apoptosis in horses

The objective of this study was to determine the effect of pulmonary intravascular macrophage depletion on systemic inflammation and ex vivo neutrophil apoptosis using an experimental model of intestinal ischemia and reperfusion injury in horses. Neutrophils were isolated before and after surgery from horses that were randomized to three treatment groups, namely, sham celiotomy (CEL, n = 4), intestinal ischemia and reperfusion (IR, n = 6), and intestinal ischemia and reperfusion with gadolinium chloride treatment to deplete pulmonary intravascular macrophages (PIMs, IRGC, n = 6). Neutrophil apoptosis was assessed with Annexin V and propidium iodide staining quantified with flow cytometry and caspase-3, caspase-8, and caspase-9 activities in neutrophil lysates. All horses experienced a systemic inflammatory response following surgery. Following surgery, ex vivo neutrophil apoptosis was significantly delayed after 12 or 24 h in culture, except in IRGC horses (12 h: CEL: P = 0.03, IR: P = 0.05, IRGC: P = 0.2; 24 h: CEL: P = 0.001, IR: P = 0.004, IRGC: P = 0.3). Caspase-3, caspase-8, and caspase-9 activities were significantly reduced in neutrophils isolated after surgery and cultured for 12 h in IR horses, but not in IRGC horses (IR caspase-3: P = 0.002, IR caspase-8: P = 0.002, IR caspase-9: P = 0.04). Serum TNF-α concentration was increased in IRGC horses for 6-18 h following jejunal ischemia. Following surgery, ex vivo equine neutrophil apoptosis was delayed via downregulation of caspase activity, which was ameliorated by PIM depletion potentially via upregulation of TNF-α.

Cytoprotective effects of molsidomine against methotrexate-induced hepatotoxicity: an experimental rat study

Introduction and aim

Methotrexate (Mtx) is an antineoplastic and immunosuppressive drug that may cause hepatotoxicity, whereas molsidomine (Mol) is a vasodilating and antioxidant agent. This study aimed to investigate the potential protective effects of Mol in Mtx-induced liver toxicity in rats.

Materials and methods

Forty Wistar albino rats were equally divided into five groups: control, Mol, Mtx, Mol–Mtx, and Mtx–Mol. Following treatment, the animals were sacrificed, and liver tissue samples were histopathologically evaluated using Roening grading and Bcl-2 antibody staining. Tissue oxidants, antioxidants, and serum transaminases were measured and statistically compared across all groups.

Results

No hepatic fibrosis or steatosis was observed in any of the groups. In the Mtx group, grade 2 liver injury and score 2 Bcl-2 antibody staining were observed; however, in the Mol–Mtx group, these were lower (grade 1, score 1). There were no statistically significant differences in serum transaminase levels among groups. Malondialdehyde levels were higher in all rats that received Mtx, but no differences in myeloperoxidase levels were observed among the groups. Levels of tissue antioxidants, including superoxide dismutase, glutathione (GSH) peroxidase (GSH-Px), and reduced GSH, were significantly higher in the Mol-treated and Mol pre-treated groups. Catalase (CAT) levels were elevated in all Mol-treated groups, but only in that group were CAT levels statistically significantly higher than in the control group.

Conclusion

Our results suggest that some oxidant levels could increase following Mtx administration in the liver, possibly contributing to liver damage, whereas Mol could mitigate the histopathological and biochemical effects of hepatotoxicity. However, molecular studies are required to understand the exact mechanisms of these alterations.

Gadolinium chloride attenuates acetic acid-evoked colitis in mice by reducing neutrophil infiltration and pro-oxidative enzyme activity

This study investigated the potential of gadolinium chloride (GdCl₃), an inhibitor of kupffer cells on the myeloperoxidase (MPO) function, both in vivo on colon inflammation model and in vitro on thioglycollate-elicited peritoneal neutrophils. Colon inflammation was induced in mice (n = 7) by 4% acetic acid (AA) enema. GdCl₃ (10 mg/kg) treatment was given 24 h before AA challenge. Clinical changes during the protocol were scored. Colons were segmented into distal and proximal parts for histological and biochemical assessment. Furthermore, myeloperoxidase (MPO) enzymes were extracted and analyzed by western blot. Short-term GdCl₃ treatment inhibited dose-dependently superoxide anion (O₂^·-), alkaline phosphatase (ALP), and MPO release and promoted neutrophil apoptosis. In vivo, low-dose GdCl₃ improved colitis scores and inhibited acute phagocyte recruitment and colon damage within the mucosa as revealed by the decrease in MPO, nitric oxide (NO), and malondialdehyde (MDA) levels. At the same time, GdCl₃ restored catalase (CAT), superoxide dismutase (SOD) activities, and reduced glutathione (GSH) levels, thus reversing the MDA/GSH ratio in both distal and proximal colons. Compared to proximal, distal colon was more altered and displayed higher pathological manifestations. Lastly, the induction of apoptosis and regulation of the major nitrosative and oxidative functions of neutrophils by GdCl₃ suggests its consideration as a beneficial tool in attenuating colon inflammation.

The Protective Effects of Gadolinum Chloride on Pneumotoxic Effects of Styrene in Rat

Objective

The aim of the present study was to evaluate the protective effects of gadoli- num on pneumotoxic effects of styrene in rats as an experimental model.

Materials and Methods

In this experimental study a total number of 40 adult male Sprague Dawley rats that weighed 200 ± 13 g were randomly divided into five groups: i. styrene (St, N=10), ii. styrene+gadolinium chloride (GdCl₃, N=10), iii. control (N=10), iv. GdCl₃ (N=5) and v. normal saline (Nor.Sal, as a solvent of GdCl₃, N=5). Normal saline, as a sham control group, was otherwise treated identically. Rats from the experimental groups were exposed to St in an exposure chamber for 6 days/week, 4 hours/day for up to 3 weeks. At the end of the experi- ment, rats from all groups were killed by deep anesthesia. Their lungs were removed, then fixed in formalin and weighed. Tissue samples were processed routinely and sections stained by the hematoxylin and eosin (H&E) and periodic acid Schiff (PAS) methods. We measured the thicknesses of the respiratory epithelia and interalveolar septa. Obtained data were ana- lyzed by ANOVA, the Tukey test and the paired t test.

Results

Shedding of apical cytoplasm in the bronchiole was a prominent feature of the St group. PAS staining revealed histochemical changes in goblet cells in the epithelium of the St group. While there were no significant changes in lung weights and respiratory epithelial thicknesses between all studied groups, statistical analysis showed a significant alteration in the thickness of interalveolar septa in the St and St+GdCl₃ group compared to the control groups (P<0.001).

Conclusion

Styrene induced structural and histochemical changes in bronchiole, interalveolar septa and alveolar organization in the rats’ lungs. Gadolinium appeared to partially reduce the toxic effects of styrene on the lungs.

Gadolinium chloride attenuates sepsis-induced pulmonary apoptosis and acute lung injury

Gadolinium chloride (GdCl₃), a Kupffer cells inhibitor, attenuates acute lung injury; however, the mechanisms behind this effect are not completely elucidated. We tested the hypothesis that GdCl₃ acts through the inhibition of lung parenchymal cellular apoptosis. Two groups of rats were injected intraperitoneally with saline or E. coli lipopolysaccharide. In two additional groups, rats were injected with GdCl₃ 24 hrs prior to saline or LPS administration. At 12 hrs, lung injury, inflammation, and apoptosis were studied. Lung water content, myeloperoxidase activity, pulmonary apoptosis and mRNA levels of interleukin-1β, -2, -5, -6, -10 and TNF-α rose significantly in LPS-injected animals. Pretreatment with GdCl₃ significantly reduced LPS-induced elevation of pulmonary water content, myeloperoxidase activity, cleaved caspase-3 intensity, and attenuated pulmonary TUNEL-positive cells. GdCl₃ pre-treatment upregulated IL-1β, -2 and -10 pulmonary gene expression without significantly affecting the others. These results suggest that GdCl₃ attenuates acute lung injury through its effects on pulmonary parenchymal apoptosis.

Endothelin receptor antagonism by tezosentan attenuates lung injury induced by aortic ischemia-reperfusion

Tezosentan is a novel dual endothelin receptor antagonist. The purpose of this study was to examine the effect of tezosentan on lung injury induced by abdominal aortic ischemia-reperfusion (IR) in rats. Thirty-two Wistar-albino rats were randomized into four groups (eight per group) as follows: control group (sham laparotomy), aortic IR group (120 min ischemia and 120 min reperfusion), aortic IR + tezosentan group (a bolus intravenous injection of 10 mg/kg tezosentan before ischemia plus continuous intravenous infusion of 1 mg/kg/hr tezosentan during 120 min ischemia and 120 min reperfusion), and control + tezosentan. Blood and lung tissue samples were obtained for biochemical analysis. Protein concentrations in bronchoalveolar lavage fluid and lung wet/dry weight ratios were measured. A histological evaluation was also done. Aortic IR significantly increased (p < 0.05 vs. control group) and tezosentan significantly decreased (p < 0.05 vs. aortic IR group) the plasma level of tumor necrosis factor-alpha; lung tissue levels of malondialdehyde, catalase, and myleperoxidase; and protein concentration in bronchoalveolar lavage fluid and lung wet/dry weight ratio. Histological evaluation showed that tezosentan attenuated the morphological changes associated with lung injury. The results of this study indicate that tezosentan attenuates lung injury induced by aortic IR in rats. We propose that this protective effect of tezosentan is due to (1) reduced systemic inflammatory response, (2) reduced oxidative stress and lipid peroxidation in lung tissue, (3) reduced pulmonary microvascular leakage, and (4) inhibition of leukocyte infiltration into lung tissue.

Tezosentan reduces the renal injury induced by abdominal aortic ischemia-reperfusion in rats

BACKGROUND

Renal injury induced by aortic ischemia-reperfusion (IR) is an important factor in the development of postoperative acute renal failure following abdominal aortic surgery. Endothelin (ET) is involved in the development of renal injury induced by aortic IR and tezosentan (R0 61-0612) is a specific ET receptor antagonist. The aim of this study was to examine the effect of tezosentan on renal injury induced by abdominal aortic IR in rats.

MATERIAL AND METHODS

Twenty-four Wistar-Albino rats were randomized into three groups (eight per group). Control group underwent laparotomy and dissection of the infrarenal abdominal aorta (IAA) without occlusion. The aortic IR group underwent laparotomy and clamping of the IAA for 120 min followed by 120 min of reperfusion. Aortic IR + tezosentan group underwent same aortic IR periods, and received a bolus intravenous injection of 10 mg/kg tezosentan before ischemia plus continuous intravenous infusion of 1 mg/kg/h tezosentan during 120 min ischemia and 120 min reperfusion. At the end of the experiment, blood and kidney tissue specimens were obtained for biochemical analysis. Histological evaluation of the rat kidney tissues was also done.

RESULTS

Biochemical analysis showed that aortic IR significantly increased (P < 0.05 versus control) while tezosentan significantly decreased (P < 0.05 versus aortic IR) the tissue levels of malondialdehyde, superoxide dismutase, catalase and myeloperoxidase. Histological analyses showed that aortic IR significantly increased (P < 0.05 versus control) while tezosentan significantly decreased (P < 0.05 versus aortic IR) focal glomerular necrosis, dilatation of Bowman's capsule, degeneration of tubular epithelium, necrosis in tubular epithelium and tubular dilatation in the renal tissue samples.

CONCLUSION

The results of this study indicate that tezosentan reduces renal injury induced by aortic IR in rats. We think that tezosentan exerted this beneficial effect via reducing oxidative stress and lipid peroxidation, inhibition of leukocyte infiltration into renal tissue and acting cytoprotective on renal tubular cells after aortic IR.

The effect of Nomega-nitro-L-arginine methyl ester and L-arginine on lung injury induced by abdominal aortic occlusion-reperfusion

PURPOSE

The aim of this study was to examine the effects of Nomega-nitro-L-arginine methyl ester (L-NAME) and L-arginine on lung injury after aortic ischemia-reperfusion (IR).

METHODS

Twenty-four Wistar-Albino rats were randomized into four groups (n = 6) as follows: Control (sham laparotomy), Aortic IR (30 min ischemia and 120 min reperfusion), L-Arginine (intraperitoneal 100 mg kg(-1) live weight)+aortic IR, and L: -NAME (intraperitoneal 10 mg kg(-1) live weight)+aortic IR. In the lung specimens, the tissue levels of malondialdehyde (MDA), vascular endothelial growth factor (VEGF), and nitric oxide (NO) were measured and a histological examination was done.

RESULTS

Aortic IR increased MDA, VEGF, and NO. L-Arginine further significantly increased MDA and NO, and decreased VEGF (P < 0.05 vs aortic IR). L-NAME significantly decreased MDA and NO (P < 0.05 vs L-arginine+aortic IR) and increased VEGF (P < 0.05 vs other groups). A histological examination showed the aortic IR to significantly increase (P < 0.05 vs control) while L-arginine also further increased (P > 0.05 vs aortic IR), whereas L-NAME caused a significant decrease in pulmonary leukocyte infiltration (P < 0.05 vs aortic IR).

CONCLUSIONS

Our results indicate that L-arginine aggravates the lung injury induced by aortic IR, while L-NAME attenuates it.

Intralysosomal accumulation of gadolinium and lysosomal damage during selective depression of liver macrophages in vivo

Kinetics of gadolinium accumulation was studied by inductively coupled plasma-emission spectroscopy after intravenous injection of this agent (7.5 mg/kg) to CBA mice. Gadolinium exhibits lysosomotropic properties (long-term selective accumulation in lysosomes in vivo). Gadolinium uptake by hepatic cells attained maximum 1 h after its intravenous injection and remained at this level during the next day. Accumulation of gadolinium in hepatocytic lysosomes disturbed their osmotic properties (as was seen from the increase in free acid phosphatase activity, which persisted for 19 days). Serum activities of beta-D-galactosidase and beta-D-glucuronidase also increased (24-72 h and day 19). Selective depression of liver macrophages (24-48 h) was accompanied by a decrease in serum chitotriosidase activity. We conclude that accumulation of gadolinium in lysosomes of liver macrophages leads to their damage and elimination of a certain population of macrophages (primarily large cells). Changes in activity of serum lysosomal enzymes also reflect repopulation of liver macrophages.

Role of Kupffer cells in acute hemorrhagic necrotizing pancreatitis-associated lung injury of rats

AIM: To investigate the role of Kupffer cells (KCs) in acute hemorrhagic necrotizing pancreatitis-associated lung injury (AHNP-LI).

METHODS: Forty-two rats were allocated to four groups [sham operation, AHNP model, gadolinium chloride (GdCl₃) pretreatment, GdCl₃ control]. In GdCl₃ pretreatment group, GdCl₃ was administered by caudal vein injection 24 h before the AHNP model induction. Blood from the iliac artery, alveolar macrophages and tissues from the pancreas and lung, were collected in six animals per group 3 and 6 h after acute pancreatitis induction. TNF-α, IL-1 of serum, myeloperoxidase (MPO) of lung tissue, NF-κB activation of alveolar macrophages were detected. Serum AST and ALT in sham operation group and GdCl₃ control group were tested. In addition, histopathological changes of the pancreas and lung were observed under light microscope.

RESULTS: MPO of lung tissue and TNF-α, IL-1 levels of serum were all reduced significantly in GdCl₃ pretreatment group compared to those in AHNP group (P <0.01). NF-κB activation of alveolar macrophages was also attenuated significantly in GdCl₃ pretreatment group compared to that in AHNP group (P <0.01). The pathological injury of the lung was ameliorated obviously in GdCl₃ pretreatment group compared to that in AHNP group. Nevertheless, the serum amylase level did not reduce and injury of the pancreas was not prevented in GdCl₃ pretreatment group.

CONCLUSION: Pulmonary injury induced by AHNP is mediated by KC activation and AHNP-LI can be significantly ameliorated by pretreatment with GdCl₃ and KCs play a vital role in AHNP-LI.

The therapeutic application of lanthanides

The biological properties of the lanthanides, based on their similarity to calcium, have stimulated research into their therapeutic application. Historical medical uses of the lanthanides and recent advances and successes will be described in the context of the biological chemistry of lanthanides, including a new metal-based drug, lanthanum carbonate, which has recently been approved as a phosphate binder for the treatment of hyperphosphatemia. This tutorial review will be of interest to those working on metal-based drugs, including inorganic chemists, and biological scientists.

Zinc may protect remote ocular injury caused by intestinal ischemia reperfusion in rats

Remote organ injury represents the oxidative damage, which occurs in various organs away from the tissues exposed to ischemia-reperfusion insult. Hypothesizing that the eye may be susceptible to this type of tissue damage, we investigated the effect of splanchnic ischemia-reperfusion on the chorio-retinal tissue in Sprague-Dawley rats. Four groups, each consisting of 10 male rats, were designed for the study. Ischemia-reperfusion was introduced by clamping superior mesenteric artery for 1 hour, followed by reperfusion for 90 min (IR group). In another group, the same operation was performed except that zinc aspartate (50 mg/kg) was given intra-peritoneally 15 min before the opening of the clamp (Zn-IR group). As control (sham group), the abdomen was opened without any intervention on superior mesenteric artery. The other group was given Zn after opening of abdomen without any intervention on superior mesenteric artery (Zn-sham group). After the choroid and the retina were dissected from the eye, malondialdehyde, superoxide dismutase, catalase and nitric oxide (NO) were measured in the collected eye tissues. We found that the levels of malondialdehyde, an indicator for lipid peroxidation, were higher in the chorio-retinal tissue of IR group compared to Zn-IR, Zn-sham or sham group (p < 0.05). The oxidative stress in Zn-IR group was not higher than that of sham group. Treatment with zinc decreased NO levels but had no noticeable effect on the level of antioxidant enzymes. Our study indicates that remote organ injury is induced in the eye during splanchnic ischemia-reperfusion and that zinc may be beneficial to ameliorate remote ocular injury.