Objective To investigate the relationship of compression area, time and weight as risky factors with local injury and systemic pathophysiological responses in rats so as to establish repeatable experimental model of crush syndrome. Methods A total of 144 male SD rats were divided into two groups, ie, mortality investigation group and biochemical indicator investigation group. Every group included the same 18 subgroups based on 18 kinds of combination with different levels of compression area (the right or both hind limbs), time (4, 6, 8 hours) and weight (2, 3, 4 kg). The circumference of the compressed hind limbs of all rats were measured and serum potassium (K+), serum creatine phosphokinase (CK), creatinine and carbamide were measured too before compression and three hours after decompression. Incidence of myoglobinuria of all rats was recorded. Muscles and kidneys were evaluated morphologically. Results The compressed hind limbs of all rats swelled significantly after three hours of reperfusion (P ＜ 0. 05). All serum K + , CK, CR and BUN were increased significantly with the increase and prolongation of the compression area, time and weight (P ＜ 0.05). Signs of direct cellular damage and ischemia-reperfusion injury were found in histology specimens of local compressed muscle.Hyperemia of glomeruli and renal tubule was found in the kidneys. Renal tubular necrosis and renal tubular cast were observed in group with compression weight ≥3 kg and compression duration ≥6 hours.Conclusions Increase and prolongation of the compression area, time and weight can aggravate the severity of crush injury. Compression area is more risky factor of severe crush injury. Both hind limbs ascompression area, compression weight ≥ 3 kg and compression duration ≥ 6 hours can be the effective experimental conditions for establishment of crush syndrome model in rats.
Key words:
Crush syndrome; Models, animal; Crush injury
Abstract Cancer chemopreventive activity of sulforaphane has been predominantly associated with its ability to induce phase II detoxification enzymes. In the present study, novel targets of sulforaphane were identified and characterized using a proteomics approach. Two-dimensional gel electrophoresis and mass spectrometry were used to produce protein profiles of human colon adenocarcinoma Caco-2 cells treated with 5 μmol/L sulforaphane for 48 h and control cells (0.05% DMSO). Gel comparisons showed the down-regulation to undetectable level of the serotonin receptor 5-HT3 after sulforaphane treatment. In addition, Aldo-keto reductase and d-dopachrome decarboxylase were also differentially expressed in control and treated cell extracts. To elucidate two-dimensional gel findings, the neurotransmitter receptors 5-HT3A, 5-HT1A, 5-HT2C, and the serotonin reuptake transporter were analyzed using Western blotting. Results showed a decrease of neurotransmitter receptors in a dose-dependent manner after sulforaphane treatment. Moreover, after exposure of Caco-2 cells to sulforaphane, nicotinic acetylcholine receptor protein level was increased. These findings suggested a potential effect of sulforaphane on serotonin release. Activation of neurotransmitter receptors followed by initiation of cyclic AMP signaling might be crucial events in colon carcinoma progression. Thus, the effect of sulforaphane may help to elucidate signaling pathways serotonin-mediated in colon cancer and lead to development of potential novel therapeutic agents. [Cancer Res 2008;68(13):5487–91]
During reperfusion of the ischemic myocardium, fatty acid oxidation rates quickly recover, while glucose oxidation rates remain low, which decreases cardiac efficiency during reperfusion. Malonyl CoA decarboxylase (MCD) degrades malonyl CoA and increases fatty acid oxidation by relieving malonyl CoA-dependent inhibition of carnitine palmitoyl transferase-1. Studies have shown that MCD inhibition improves reperfusion recovery of ischemic hearts ex vivo by reducing fatty acid oxidation rates and increasing glucose oxidation rates. The objective of this study was to determine whether MCD inhibition would translate into a reduction in infarct size. Wild Type (WT, n = 7) or MCD deficient (MCD−/−, n = 7) mice had their left anterior descending coronary artery ligated for 30 min followed by 24 hr reperfusion. MCD−/− mice demonstrated a dramatic reduction in infarct size compared to WT mice (10.8±3.8 vs. 39.5±4.7 % of area at risk, P < 0.05) despite similar areas at risk (53 vs. 52 % of left ventricle). Furthermore, malonyl CoA levels were higher in the area at risk of hearts from MCD−/− mice (3.9±0.7 vs. 1.9±0.5 nmol/g wet weight, P < 0.05). Because the protection against ex vivo ischemia/reperfusion injury in MCD−/− mice was associated with increased myocardial glucose oxidation rates, secondary to an inhibition of fatty acid oxidation, we next determined whether direct stimulation of pyruvate dehydrogenase (PDH) and subsequent glucose oxidation would also afford protection against myocardial infarction. Infusion of the PDH activator, dichloroacetate (100 mg/kg intraperitoneal injection, followed by hourly injections of 50 mg/kg for the 24 hr duration of reperfusion), demonstrated significant protection against myocardial infarction (36.4±2.4 vs. 50.3±3.2 % of area at risk, P < 0.05). We demonstrate that MCD inhibition is beneficial against ischemia/reperfusion injury, possibly due to its effects on glucose oxidation stimulation, validating the optimization of myocardial metabolism as a novel therapy for ischemic heart disease.
Objective
To investigate the dynamic changes of endoplasmic reticulum stress-related molecules including glucose regulated protein (GRP78), C/EBP homologous protein (CHOP), and caspase-12 in sciatic nerve of diabetic rats and explore its mechanisms.
Methods
Rats were randomly divided into normal control group (NC) and diabetes mellitus group (DM) that were induced by intraperitoneal injection of Streptozocin after 4 weeks of high-fat chow feeding. Sciatic nerves were isolated for three times at 4 weeks, 8 weeks and 12 weeks after induction of diabetes. The expressions of GRP78, CHOP, and caspase-12 were detected with quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analyses. The morphology of sciatic nerve was investigated with electron microscope.
Results
With the extension of the course, demyelinating and axonal injury appeared in sciatic nerve of diabetic rats. The expressions of GRP78 mRNA and protein in DM group were significantly higher than NC group at 4 weeks and 8 weeks after induction of diabetes(P<0.05, P<0.01). The expressions of CHOP mRNA and protein in DM group were significantly higher than NC group at 8 weeks and 12 weeks after induction of diabetes (P<0.05). The expressions of caspase-12 mRNA and protein in DM group were significantly higher than NC group at 8 weeks after induction of diabetes(P<0.05, P<0.01).
Conclusions
Endoplasmic reticulum stress-related molecules (GRP78, CHOP, and caspase-12) contributed to the peripheral nerve injury of diabetic rats, and displayed dynamic changes.
Key words:
Endoplasmic reticulum; Stress; Diabetic neuropathies/ME; Peripheral nervous system diseases/CO/ME; Membrane proteins/ME; Transcription factor CHOP/ME; Caspase 12/ME
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