ABSTRACT
Objective:To investigate the protective effect of β- blocker (esmolol) on myocardia and toll-like receptor 4 (TLR4) inflammatory pathway in septic rats.Methods:Sixty male Wistar rats were randomly (random number) divided into the shame group, sepsis group (CLP group), esmolol group (CLP+ES group) and TLR4 inhibitor group (CLP+TAK-242 group) with 15 rats in each group. Cecal exploration was performed in the shame group, and cecal ligation and perforation (CLP) was performed in the CLP group, CLP+ES group and CLP+TAK-242 group. The CLP+ES group received intraperitoneal injection of esmolol diluent 20 mg/kg 12 h after CLP. The CLP+TAK-242 group was given intraperitoneal injection of TAK-242 3 mg/kg at the same time point as above. The shame group and CLP group were given the same amount of normal saline. Rats in all groups were sacrificed 24 h after operation, and the samples were collected and processed. The pathological changes of myocardium were observed by hematoxylin - eosin staining. The expression of TLR4, myeloid differentiation protein 88 (MyD88) and nuclear factor -κB (NF-κB) in myocardial tissue were observed by immunohistochemistry. Masson staining was used to observe the expression of fibers and inflammatory factors in myocardial tissue. The protein expressions of TLR4, MyD88, NF-κB and aspartic acid specific cysteine protease 1 (caspase-1) were detected by Western blot. Serum levels of cardiac troponin I (cTn-I), tumor necrosis factor α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) were detected by enzyme-linked immunosorbent assay (ELISA).Results:Compared with the shame group, myocardial injury, fibrosis and inflammatory cell infiltration were significantly aggravated in the CLP group, and the levels of myocardial injury index cTn-I and inflammatory mediators TNF-α, IL-6 and IL-1β were significantly increased [(8.70±0.22) vs. (4.41±0.31), (445.57±9.13) vs. (219.60±5.52), (165.55±2.18) vs. (93.47±3.37), (124.12±2.59) vs. (67.63±6.04),all P<0.05]. Compared with the CLP group, myocardial injury was significantly reduced in the CLP+ES group and CLP+TAK-242 group, and the levels of inflammatory transmitters were significantly reduced [(5.38±0.18) and (5.37±0.13) vs. (8.70±0.22), (322.73±7.63) and (300.58±17.47) vs. (445.57±9.13), (121.28±5.44) and (120.30±4.95) vs. (165.55±2.18), (102.60±4.09) and (105.08±7.21) vs. (124.12±2.59), all P<0.05]. Western blot analysis showed that the protein expression levels of TLR4, MyD88, NF-κB and caspase-1 in the CLP group were significantly higher than those in the shame group [(1.79±0.15) vs. (1.15±0.04), (4.70±0.30) vs. (3.87±0.10), (0.35±0.04) vs. (0.18±0.02), (2.27±0.29) vs. (1.15±0.07), all P<0.05], while the protein expression levels in the CLP+ES group and CLP+TAK-242 group were significantly lower than those in the CLP group [(1.31±0.16) and (1.18±0.14) vs. (1.79±0.15), (1.50±0.16) and (1.46±0.19) vs. (2.27±0.29), (0.27±0.02) and (0.24±0.01) vs. (0.35±0.04), (1.50±0.16) and (1.46±0.19) vs. (2.27±0.29), all P<0.05]. Conclusions:β-blocker can reduce myocardial injury and inhibit the expression of inflammatory mediators in septic rats by blocking the inflammatory response mediated by TLR4 signaling pathway.
ABSTRACT
ObjectiveTo investigate the effect of Chuanshanlong granule on Toll-like receptor 4 （TLR4）/myeloid differentiation protein 88 （MyD88）/nuclear transcription factor -κB （NF-κB） signaling pathway， and to explore the mechanism of its treatment of autoimmune thyroiditis （AIT） in rats. MethodForty AIT models were established following excess iodine and injection of porcine thyroglobulin and Freund's adjuvant into Lewis rats for six weeks. Then the rats were randomly divided into the model group， Chuanshanlong granule low-， medium- and high-dose group （0.52， 1.03， 2.06 g·kg-1·d-1）， with ten in each group. Rats in the Chuanshanlong granule low-， medium- and high-dose groups were separately given 0.01 mL·g-1·d-1 Chuanshanlong granule， and those in the normal group and the model group were given the same volume of deionized water for eight weeks. Serum of rats was taken to measure thyroglobulin antibody （TgAb） and thyroid peroxidase antibody （TPOAb） by enzyme-linked immunosorbent assay （ELISA）， and the concentrations of free triiodothyronine （FT3）， free thyroxine （FT4） and thyroid stimulating hormone （TSH） were detected. The rat thyroid lobes were stained with hematoxylin and eosin （HE）， and the pathological changes were observed under light microscope. In addition， the relative expression of TLR4， MyD88， NF-κB protein and mRNA was determined by immunohistochemistry and real-time polymerase chain reaction （Real-time PCR）. ResultCompared with the conditions in the normal group， the serum concentrations of TPOAb and TgAb （P<0.01） and FT3 and FT4 （P<0.01） increased and TSH decreased （P<0.01） in the model group. Compared with the conditions in the model group， the concentrations of TPOAb and TgAb in the Chuanshanlong granule treatment groups reduced （P<0.01）， and the concentrations of FT3 and FT4 were lowered （P<0.01） while TSH increased （P<0.01） in the Chuanshanlong granule high-dose group. HE staining showed that there was lymphocyte infiltration in the thyroid follicular space， a large number of destroyed or diminished follicular cavities， decreased colloid content， and thinned or destroyed follicular wall in the model group， while the thyroid lymphocyte infiltration in the Chuanshanlong granule treatment groups was significantly less and the structure of thyroid follicles was more complete than those in the model group. Compared with the normal group， the model group had up-regulated relative expression of TLR4， MyD88 and NF-κB protein （P<0.01） and mRNA （P<0.01）. Compared with the model group， the Chuanshanlong granule high-dose group had down-regulated relative expression of TLR4 protein and mRNA （P<0.05）， MyD88 protein （P<0.01） and mRNA （P<0.05）， and NF-κB protein and mRNA （P<0.01）. ConclusionChuanshanlong granule may play a therapeutic role in AIT by inhibiting the activation of TLR4/MyD88/NF-κB signaling pathway.
ABSTRACT
Cardiac remodeling involves changes in heart shape, size, structure, and function after injury to the myocardium. The proinflammatory adaptor protein myeloid differentiation protein 88 (MyD88) contributes to cardiac remodeling. To investigate whether excessive MyD88 levels initiate spontaneous cardiac remodeling at the whole-organism level, we generated a transgenic MyD88 mouse model with a cardiac-specific promoter. MyD88 mice (male, 20-30 g, n=∼80) were born at the expected Mendelian ratio and demonstrated similar morphology of the heart and cardiomyocytes with that of wild-type controls. Although heart weight was unaffected, cardiac contractility of MyD88 hearts was mildly reduced, as shown by echocardiographic examination, compared with wild-type controls. Moreover, the cardiac dysfunction phenotype was associated with elevation of ANF and BNP expression. Collectively, our data provide novel evidence of the critical role of balanced MyD88 signaling in maintaining physiological function in the adult heart.