OBJECTIVETo investigate the protective effect of exogenous inhibitor of matrix metalloproteinases-9 (MMP-9), batimastat, in the lung injury induced by cardiopulmonary bypass (CPB) in dogs.

METHODSThirty healthy mongrel puppies were randomly divided into 3 groups: control group, low-dose group [batimastat 10 mg/(kg.d) for 3 days before operation] and high-dose group [batimastat 30 mg/(kg.d) for 3 days before operation]. The off-pump puppies' model of acute lung injury was established, and hemodynamic and respiratory parameters were monitored. The preoperative and postoperative alveolar-arterial oxygen difference (A-aDO(2)) and respiratory index (RI) were calculated. From the beginning of surgery, blood samples were taken at the time 0, 60, 120, and 270 min. Plasma concentrations of MMP-9 were measured by ELISA, and blood MMP-9 mRNA expressions were determined by RT-PCR. The myeloperoxidase (MPO) activity of centrifugal bronchoalveolar lavage fluid were measured by Colorimetry. And MMP-9 activity was determined by Gelatin zymography. Light and electronic microscope were used to observe the morphological changes of lung tissue. A small piece of left lung tissue was taken, weighed and baked to calculate the wet weight (W/D) index.

RESULTSAfter cardiopulmonary bypass, the concentrations of MMP-9 and mRNA expressions of the control group were increased significantly, and lung injury was apparent. At 270 min, the MMP-9 plasma concentration of high-dose group (17.36 +/- 1.18) microg/L was significant reducing than control group (30.47 +/- 2.22) microg/L (P < 0.05). After operation, A-aDO(2) and RI of high-dose group were significantly improved than control group (P < 0.05). The W/D index of the high-dose group (2.8 +/- 0.48) was significantly lower than that of control group (4.7 +/- 0.6) (P < 0.05). And the pathological changes of lung tissue were significantly improved in the high-dose group. However, there was no significant difference in the MMP-9 mRNA expression in three groups.

CONCLUSIONSBatimastat plays a role in the protection of the lung injury of CBP by reducing the concentration and activity of MMP-9, the degradation of the cell membrane and pulmonary neutrophil infiltration and reduction of pulmonary edema.

Acute Lung Injury ; etiology ; prevention & control ; Animals ; Cardiopulmonary Bypass ; Disease Models, Animal ; Dogs ; Lung ; pathology ; Matrix Metalloproteinase 9 ; metabolism ; Matrix Metalloproteinase Inhibitors ; Phenylalanine ; analogs & derivatives ; pharmacology ; Postoperative Complications ; prevention & control ; Thiophenes ; pharmacology

OBJECTIVETo investigate the effect and potential mechanism of lysophosphatidic acid (LPA) and antiarrhythmic peptide (AAP10) on rabbit ventricular arrhythmia.

METHODSTwenty-four rabbits were randomly divided into three groups (n = 8 each): control group, LPA group and AAP10 + LPA group. Using arterially perfused rabbit ventricular wedge preparations, transmural ECG and action potentials from both endocardium and epicardium were simultaneously recorded in the whole process of all experiments with two separate floating microeletrodes. The incidence of ventricular arrhythmia post S1S2 stimulation was recorded. Protein levels of nonphosphorylated Cx43 and total Cx43 were evaluated by Western blot. The distribution of nonphosphorylated Cx43 was observed by confocal immunofluorescence microscopy.

RESULTSCompared with the control group, the QT interval, endocardial action potential duration, transmural repolarization dispersion (TDR) and incidence of ventricular arrhythmia were significantly increased and nonphosphorylated Cx43 expression was significantly upregulated in the LPA group. Compared with the LPA group, cotreatment with AAP10 can reduce the QT interval, endocardial action potential duration, TDR and incidence of ventricular arrhythmia (25.0% vs 62.5%, P < 0.01) and downregulate nonphosphorylated Cx43.

CONCLUSIONSLPA could promote the arrhythmia possibly by upregulating nonphosphorylated Cx43 and subsequent gap junction transmission inhibition. Gap junction enhancer AAP10 could attenuate the pro-arrhythmic effect of LPA probably by downregulating myocardial nonphosphorylated Cx43 expression.

Animals ; Anti-Arrhythmia Agents ; pharmacology ; Arrhythmias, Cardiac ; chemically induced ; metabolism ; physiopathology ; Connexin 43 ; metabolism ; Lysophospholipids ; adverse effects ; Oligopeptides ; pharmacology ; Rabbits

Objective To study the Kv1.3 channel expression changes after CD4 + and subsets CD28null/CD28+T cells activation in peripheral blood of patients with acute coronary syndrome (ACS).Methods CD4+ T cell in 27 ACS patients and CD4+ CD28null/CD4+ CD28 + T cells in 12 out of these 27 ACS patients were isolated from peripheral blood with magnetic cell sorting.The whole-cell Kv1.3 currents for three T cells were recorded with patch-clamp technique before and 72 hours after activation by purified anti-human CD3 Interferon gamma,tumor necrosis factor alpha(TNF-α),granzyme B mRNA expression were determined by reverse transcription-PCR before and 72 hours after activation by purified anti-human CD3 in the presence or absence of recombinant Margstoxin (rMgTX,0.1,1,10 nmol/L),a specific Kv1.3 channel blocker.Results Peak Kv1.3 channel currents of CD4 + ,CD4+ CD28null,CD4+ CD28 + T cells were significantly increased and the mean Kv1.3 channel numbers per cell of these cells were increased by about 90%,60%,80% (402 ± 88 vs.752 ± 275,553 ± 328 vs.874 ± 400,392 ± 133 vs.716 ± 251,all P <0.05) after activation compared to baseline values.Baseline CD4+ CD28nullT cell numbers were about 40% more than those of CD4+ CD28+ T cell (P < 0.05) and were similar after activation (P = 0.102).The mRNA expression of interferon gamma,TNF-α and granzyme B were dose-dependently down-regulated by rMgTX.Conclusions Kv1.3 channels of peripheral CD4 + T cell and CD28null/CD28 + T cells from ACS patients significantly increased after activation and Kv1.3-specific channel blocker rMgTX could effectively abolish this effect suggesting a potential role of Kv1.3 channel blocker on plaque stabilization in ACS patients.