ABSTRACT
To investigate the protective effects of recombinant human tumor necrosis factor receptor II: IgG Fc fusion protein (rhu TNFR: Fc) against the lipopolysaccharide (LPS) induced intestinal damage of rats and its underlying mechanism. SD rats were randomly divided into four groups: control group, rhuTNFR: Fc group, LPS group and rhu TNFR: Fc + LPS group. Mean arterial pressure (MAP) was continuously monitored and the mortality rates were assessed. The levels of TNF-alpha and its bioactivity in the serum were assessed by ELISA and flow cytometry respectively. Pathologic changes of intestinal tissue were observed by HE staining. The rats of control and rhu TNFR: Fc group all survived with stable MAP, and the low level and bioactivity of TNF-alpha in the serum were maintained. While 83% of the rats in LPS group died by 6 h with the levels and bioactivity of TNF-alpha increasing significantly. In rhu TNFR: Fc + LPS group, the mortality rate of rats dropped to 33%. The TNF-alpha level increased compared with control group but its bioactivity decreased significantly compared with LPS group. The MPO activity and content of MDA decreased significantly. The status of pathological manifestation in the intestine was also ameliorated. These data suggest that rhu TNFR: Fc could protect rats from the acute intestine injury induced by LPS through ablating the rise in serum TNF-alpha level and bioactivity as well as anti-oxidation.
Subject(s)
Animals , Female , Humans , Male , Rats , Disease Models, Animal , Etanercept , Immunoglobulin G , Pharmacology , Intestines , Metabolism , Pathology , Lipopolysaccharides , Rats, Sprague-Dawley , Receptors, Tumor Necrosis Factor , Receptors, Tumor Necrosis Factor, Type II , Pharmacology , Recombinant Fusion Proteins , Pharmacology , Tumor Necrosis Factor-alpha , MetabolismABSTRACT
<p><b>OBJECTIVES</b>To block the synthesis of ryanodine receptor 2 (RyR2) in myocardial cells by RNA interference and to investigate its biological impact on ischemia-reperfusion (I/R) in rat myocardial cells.</p><p><b>METHODS</b>Rat myocardial cells were isolated and cultured for an I/R model in vitro. RNA interference technique was used to block the synthesis of RyR2 in myocardial cells. Changes of LDH level, apoptosis, RyR2 mRNA expression and cytosolic Ca(2+) concentration were analyzed accordingly.</p><p><b>RESULTS</b>Myocardial cells after I/R manipolation were severely injuried (LDH leakage, 125 IU/L vs 12 IU/L, P < 0.05), apoptosis (60.1% vs 5.5%, P < 0.05), significant cytosolic Ca(2+) overload (21.2 vs 7.6, P < 0.05) and remarkable mitochondrial membrane potential loss (37.2 vs 85.1, P < 0.05). However, no visible change of RyR2 was observed (20.1 vs 22.7, P > 0.05). Pre-treatment with RyR2 specified siRNA demonstrated suppressed expression of RyR2 (6.8 vs 20.1, P < 0.05), increased mitochondrial membrane potential (55.8 vs 37.2, P < 0.05), attenuated cytosolic Ca(2+) overload (8.6 vs 21.2) and cellular apoptosis (31.2% vs 60.1%, P < 0.05).</p><p><b>CONCLUSION</b>RyR2 gene silencing enables to protect myocardial cells from I/R injury in vitro.</p>