Resolvin D1 Group Research Articles

Identifying the shared genes and KEGG pathways of Resolvin D1-targeted network and osteoarthritis using bioinformatics

ABSTRACT Osteoarthritis (OA) is a common chronic degenerative disease characterized by the loss of articular cartilage, which causes loss of joint function and reduce quality of life. Resolvin D1 (RvD1) has shown interesting anti-inflammatory effects; however, the mechanism of action of RvD1 in OA remains unclear. The aim of this study was to investigate the potential mechanism of RvD1 in OA by bioinformatics and partial in vitro mechanisms. Here, 106 shared differentially expressed genes (DEGs) were identified based on the GSE82107, GSE55235, GSE55457 dataset; 700 DEGs were identified based on GSE169077. Enrichment analyses of these genes were then successively conducted. RvD1-targeted genes and KEGG pathways are identified by STITCH. 27 shared KEGG pathways were identified among RvD1-targeted pathways and OA. Furthermore, cell apoptosis assay, western blotting, real-time fluorescent quantitative PCR (qRT-PCR), enzyme linked immunosorbent assay (ELISA) were used to confirm the expression levels of the key genes of shared Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways between RvD1-targeted and OA in IL-1β treated rat knee chondrocytes. The results showed that RvD1-targeted pathways and the expression of nuclear p65, p53, and p-JNK were inhibited in the RvD1 group compared with the IL-1β group. Thus, the findings indicate that RvD1 may inhibit the development of OA through NF/kB, p53, MAPK/JNK, PI3K-AKT signaling pathways, and act as a treatment for OA.

Mechanism of action of resolvin D1 in inhibiting the progression of aortic dissection in mice.

BackgroundTo investigate the protective effect of resolvin D1 (RvD1) on aortic dissection (AD) in mice and explore the related mechanisms.MethodsMice were randomly divided into a blank group, model group, and RvD1 group. The RvD1 and model groups were administered 0.4% β-aminopropionitrile (BAPN) solution, while the blank group was administered distilled water. When the experiment began, whether mice had AD was determined by echocardiogram. The RvD1 group was also administered RvD1 (30 µg/kg), while the model and blank groups were administered saline intraperitoneally. After 21 d, body weight trend and survival rate in the three groups were compared. The diameter of the ascending aorta of mice was detected by echocardiography. Then, the mice were sacrificed, and histopathological staining procedures were performed. Enzyme-linked immunosorbent assay (ELISA) was used to detect cytokines and chemokines in blood and tissue, respectively.ResultsAt 21 d, there was no statistically significant difference in body weight between three groups (P>0.05). The survival rate showed a significant difference between the RvD1 and model group (P<0.05). Echocardiography revealed that compared with the RvD1 and blank groups, aortic dilatation was significant in the model group. Pathological staining showed that the destruction of the aortic wall structure and inflammatory cell infiltration were more noticeable in the model group than in the RvD1 group. A slight disintegration of elastic fibers and collagen in the aorta was observed in the RvD1 group, and the aortic structure was clear. The results of ELISA showed that the inflammatory factors levels in the RvD1 group, although higher than those in blank group, were significantly decreased compared with the model group. The ELISA results of AD tissue showed that at 21 d, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels in the aorta were significantly decreased in the RvD1 group compared with the model group (P<0.05).ConclusionsAdministration of RvD1 significantly delayed aortic dilation and disintegration and inhibited local macrophage and neutrophil infiltration in the early stages of aortic injury. Moreover, RvD1 significantly downregulated the expression of cytokines and chemokines in aortic tissues and serum and improved aortic remodeling.

Resolvin D1 alleviates cerebral ischemia/reperfusion injury in rats by inhibiting NLRP3 signaling pathway.

The purpose of the present study was to investigate the role of resolvin D1 (RvD1) in cerebral ischemia/ reperfusion (I/R) injury in rats and its mechanism. A total of 60 adult male Wistar rats were divided into 3 groups using a random number table, including sham-operation group (Sham group, n=20), cerebral I/R injury group (I/R group, n=20) and cerebral I/R injury + RvD1 pretreatment group (I/R + RvD1 group, n=20). The model of focal I/R injury was established using suture method through 30 min of ischemia and 24 h of reperfusion. In I/R + RvD1 group, the rats were intraperitoneally injected with RvD1 (4 mg/kg/d) at 7 d before operation, while those in the Sham group and I/R group were injected with an equal volume of normal saline. After reperfusion, the area of cerebral infarction was evaluated by means of 2,3,5-triphenyltetrazolium chloride (TTC) staining. Then hematoxylin and eosin (H&E) staining was applied to observe the status of brain tissue injury in each group of rats, and the expression of malondialdehyde (MDA), a marker of oxidative stress, in each group of brain tissues was detected via an oxidative stress detection kit. Moreover, reverse transcription-polymerase chain reaction (RT-PCR) assay was performed to measure the levels of inflammation-related genes [interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α)] in the brain tissues of each group of rats, and the neuronal apoptosis level in the brain tissues in each group was determined through terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Finally, the expression levels of proteins related to the inflammasome signaling pathway were detected via Western blotting assay. It was indicated in the results of TTC staining and H&E staining that RvD1 could remarkably decrease the area of I/R-induced cerebral infarction and relieve nervous tissue injury (P<0.05). The results of TUNEL staining revealed that the cerebral neuronal apoptosis induced by I/R injury was alleviated by RvD1 (P<0.05). In addition, RvD1 lowered the levels of inflammatory factors and MDA in the brain tissues of rats with I/R injury (P<0.05). Furthermore, it was discovered that RvD1 repressed the protein expression of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) in the brain tissues of rats with I/R injury (P<0.05). The protective effect of RvD1 on the rats against cerebral I/R injury may be related to its inhibition on NLRP3 inflammasome, and RvD1 is expected to become a targeted drug for the clinical treatment of cerebral I/R injury.

Role and related mechanism of resolvin D1 in lung ischemia reperfusion injury in rats

Objective: To investigate the role and related mechanism of resolvin D1 (RvD1) in lung ischemia-reperfusion injury (LIRI) in rats. Methods: Forty male Sprague-Dawley rats, 7-8 weeks, weighing 220-280 g, were divided into 4 groups using a random number table method: sham operation group, lung ischemia reperfusion control group, normal saline group, and RvD1 group. The rat model of LIRI was produced by 45 min of occlusion of the left hilum of lungs followed by 150 min reperfusion. In sham group, no blocking of the left hilum of lung after thoracotomy; Normal saline 2 ml/kg and RvD1 100 μg/kg were injected respectively at 10 min of reperfusion in normal saline group and RvD1 group. Blood samples were collected from the femoral vein for determination of interleukin (IL)-6, tumor necrosis factor (TNF)-α, soluble inter-cell adhesion molecules (sICAM-1) concentrations at 150 min of reperfusion. The rats were sacrificed after collection of blood samples and then lung tissues were taken for observation of the pathological changes and for measurement of lung wet/dry weight ratio (W/D). The the contents of malondialdehyde (MDA), monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-2 and the activity of myeloperoxidase (MPO) in lung tissues were determined. The protein relative expression of nuclear factor (NF)-κB in lung tissues was detected by Western blot. Lung tissue cell apoptosis was detected with TUNEL method. Results: The plasma level of IL-6, TNF-α, sICAM-1 in normal saline group and RvD1 group were significantly higher than those in the Sham group [(110±7), (100±4) vs (72±3) ng/L, (151±8), (153±6) vs (104±5) ng/L, (2 690±133), (2 760±167) vs (1 953±125) ng/L]. Besides, NF-κB protein relative expression level of lung tissues up-regulated [(0.681±0.033), (0.664±0.024) vs (0.292±0.011)] (all P<0.05). The W/D, apoptosis index, MDA, MCP-1, MIP-2 contents and MPO activity in lung ischemia reperfusion control group, normal saline group and RvD1 group were significantly higher than those in the Sham group [(5.92±0.31), (5.85±0.24), (5.06±0.08) vs (4.14±0.10), (32.9±1.5)%, (31.9±1.3)%, (17.7±1.8)% vs (8.1±0.6)%, (72.1±2.3), (66.7±3.7), (34.0±1.4) vs (22.0±0.8) nmol/mg, (3.99±0.28), (3.86±0.25), (2.66±0.16) vs (1.47±0.17) pg/mg, (9.45±0.53), (9.68±0.62), (7.62±0.22) vs (4.70±0.41) pg/mg, (3.01±0.18), (2.92±0.19), (1.58±0.11) vs (0.98±0.07) U/g] (all P<0.05). The plasma levels of the cytokines mentioned above, the W/D, the apoptosis index, MDA, MCP-1, MIP-2 contents and MPO activity in RvD1 group were significantly lower than those in the lung ischemia reperfusion control group [(63±4) vs (110±7) ng/L, (90±8) vs (151±8) ng/L, (1 835±182) vs (2 690±133) ng/L, (5.06±0.08) vs (5.92±0.31), (17.7±1.8)% vs (32.9±1.5)%, (34.0±1.4) vs (72.1±2.3) nmol/mg, (2.66±0.16) vs (3.99±0.28) pg/mg, (7.62±0.22) vs (9.45±0.53) pg/mg, (1.58±0.11) vs (3.01±0.18) U/g]. Besides, NF-κB protein relative expression level of lung tissues down-regulated [(0.313±0.012) vs (0.681±0.033)] (all P<0.05). Inflammatory cell infiltration in LIRI groups increased significantly, while it was significantly reduced in RvD1 group. Conclusion: RvD1 can effectively alleviate the tissue damage caused by lung ischemia-reperfusion through down-regulating NF-κB expression, relieving inflammatory reaction and oxidative stress, reducing apoptosis in rats.

Resolvin D1 Resolve Inflammation in Experimental Acute Pancreatitis by Restoring Autophagic Flux.

Acute pancreatitis (AP) is a common acute gastrointestinal disorders. Increasing evidence indicated that autophagy is involved in the development of AP. Resolvin D1 is an endogenous pro-resolving lipid mediator, which can protect mice from cerulein-induced acute pancreatitis and facilitate autophagy in macrophage, but its mechanism remians unclear. To investigate the effect of resolvin D1 on autophagy in mouse models of cerulein-induced AP. C57BL/6 mice were randomly divided into control group, AP group and resolvin D1 group. The models of cerulein-induced AP were constructed by intraperitoneally cerulein. Resolvin D1 group was established by intraperitoneally resolvin D1 based on AP models, simultaneously, control group received normal saline. The severity of AP, the level of inflammatory cytokines, the number of autophagic vacuoles, and the expression of autophagy-related markers were evaluated among three groups. The AP models were established successfully. Compared to control group, the number of autophagic vacuoles and expressions of autophagy-related markers including Beclin-1, p62 and LC3-II were increased in AP models, In contrast, the degree of inflammation and levels of inflammatory cytokines in AP models were reduced after resolvin D1 treatment. Moreover, resolvin D1 attenuated the number of autophagic vacuoles and expressions of autophagy-related markers. Autophagic flux is impaired in cerulein-induced AP. Resolvin D1 ameliorate the severity of mice with cerulein-induced acute pancreatitis, possible attributing to its reducing impaired autophagy and restoring autophagic flux.

Effects of resolvin D1 on the autophagy in acute pancreatitis in mice

Objective To investigate the effects of resolvin D1 on autophagy in the prevention of acute pancreatitis (AP) in mice. Methods Thirty C57BL/6 mice were divided into control group, AP group and resolvin D1 group. AP model was established by intraperitoneal injection of cerulein at 50 μg·kg-1·h-1. Resolvin D1 was intraperitoneally given at 50 μg/kg one hour before and four hours after modeling. The mice of control group were intraperitoneally injected the same volume of 0.9% sodium chloride solution. The serum levels of amylase and lipase were measured by colorimetric method. The pathological injury of the lung and pancreatitis were observed under optical microscope. Autophagic vacuoles in acinar cells of pancreas of mice were evaluated by transmission electron microscope. And the expressions of autophagy related markers Beclin-1, p62 and LC3-Ⅱ at the mRNA and protein levels in pancreas of mice were detected by real time quantitative polymerase chain reaction (RT-qPCR) and Western blotting method. One-way analysis of variance and SNK-q were performed for statistical analysis. Results There were statistically significant differences in serum amylase and lipase levels between control group, AP group and resolvin D1 group (F=62.99 and 149.69, both P<0.01). The serum amylase and lipase levels of mice in resolvin D1 group were lower than those of AP group ((525.08±41.12) U/L vs. (752.62±42.03) U/L, (758.24±134.77) U/L vs. (1 201.06±112.53) U/L), and the differences were both statistically significant (both SNK-q test and P<0.01). In addition, there were statistically significant differences in the ratio of the pancreas and lung wet mass to body mass between control group, AP group and resolvin D1 group (F=11.36 and 18.51, both P<0.05). Pathological injury scores of pancreas and lung of resolvin D1 group were both lower than those of AP group (3.3±0.6 vs. 5.6±0.6, 5.4±0.5 vs. 8.8±0.4), and the differences were statistically significant (both SNK-q test and P<0.05). The results of transmission electron microscopy observation revealed that the number of autophagic vacuole of resolvin D1 group was less than that of AP group, and the size was smaller. Moreover, there were statistically significant differences in Beclin-1, p62 and LC3-Ⅱ mRNA between control group, AP group and resolvin D1 group (F=270.95, 151.83 and 124.77, all P<0.05). The relative expression mRNA levels of Beclin-1, p62 and LC3-Ⅱ of resolvin D1 group were 1.59±0.12, 2.75±0.27 and 1.34±0.14, respectively, which were lower than those of AP group (2.68±0.13, 3.32±0.30 and 3.37±0.26, respectively), and the differences were statistically significant (all SNK-q test and P<0.05). There were statistically significant differences in the expressions of Beclin-1, p62 and LC3-Ⅱat the protein level between control group, AP group and resolvin D1 group (F=116.63, 384.40 and 192.45, all P<0.05). The expressions of Beclin-1, p62 and LC3-Ⅱ at protein level of resolvin D1 group were 0.98±0.03, 0.57±0.04 and 0.31±0.03, respectively, which were lower than those of AP group (1.34±0.07, 1.02±0.03 and 0.48±0.04, respectively), and the differences were statistically significant (all SNK-q test and P<0.05). Conclusion Resolvin D1 ameliorates the severity of AP by attenuating the impaired autophagy and restoring autophagic flux in AP mice. Key words: Autophagy; Acute pancreatitis; Resolvin D1; Mice

The effects of resolvin D1 on myocardial dysfunction after cardiopulmonary resuscitation in swine and its potential mechanisms

Objective To establish a porcine model of cardiopulmonary resuscitation to explore the effectiveness of resolvin D1 in improving post-resuscitation myocardial dysfunction and its potential mechanisms. Methods Twenty-eight male domestic pigs weighing 36±3 kg were utilized. The pig model was established by 8 mins of untreated ventricular fibrillation and then 5 mins of cardiopulmonary resuscitation. The animals were randomly divided into 4 groups (n=7 each): sham operation group (group S), cardiopulmonary resuscitation group (group CPR), low-dose resolvin D1 group (group LRD), and high-dose resolvin D1 group (group HRD). The animals in group S only got the general preparation without the procedure of cardiac arrest and resuscitation. At 5 min after resuscitation, the doses of resolvin D1 0.3 μg/kg and 0.6 μg/kg were respectively injected via the femoral vein of pigs in LRD and HRD groups, and meanwhile the equal volume of vehicle was given into the animals in the other two groups. At 3 h, 6 h and 24 h after resuscitation, the changes of stroke volume (SV) and global ejection fraction (GEF) were evaluated by a PiCCO monitor, and meanwhile the concentration of cardiac troponin I (cTNI) in serum was measured. At 24 h after resuscitation, the pigs were sacrificed, and myocardial tissue was obtained for the determination of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), malondialdehyde (MDA), and superoxide dismutase (SOD) activity. Results Compared with group S, significantly decreased SV and GEF and markedly increased concentration of serum cTNI were observed in the other three groups with post-resuscitation myocardial dysfunction (all P<0.05). Compared with group CPR, the values of SV and GEF were significantly increased while the concentration of serum cTNI was significantly decreased in LRD and HRD groups[SV(ml): 28±5, 31±5 vs. 23±4 at 3 hrs, 32±3, 36±6 vs. 27±6 at 6 hrs, 35±5, 41±5 vs. 29±5 at 24 hrs; GEF(%): 17±2, 19±2 vs. 14±1 at 3 hrs, 20±2, 23±3 vs. 16±3 at 6 hrs, 23±2, 26±3 vs. 20±2 at 24 hrs; cTNI (pg/ml): 247±34, 230±26 vs. 324±56 at 3 hrs, 553±37, 501±34 vs. 611±44 at 6 hrs, 436±23, 371±29 vs. 553±47 at 24 hrs, all P<0.05]. Compared with group LRD, myocardial function and serum markers were further significantly improved in group HRD (all P<0.05). The inflammation and oxidative stress in myocardial tissue were observed in all the animals experiencing cardiac arrest and resuscitation, which were indicated by increased levels of TNF-α, IL-6 and MDA and decreased SOD activity. Compared with group CPR, the levels of TNF-α, IL-6 and MDA were significantly decreased while SOD activity was significantly increased in LRD and HRD groups[TNF-α(pg/ml): 442±87, 218±55 vs. 653±112; IL-6(pg/ml): 563±68, 403±61 vs. 824±117; MDA(nmol/mg): 3.95±0.96, 2.54±1.21 vs. 6.37±1.26; SOD(U/mg): 2.27±0.93, 3.36±0.74 vs. 0.89±0.31, all P<0.05]. The morbidity of myocardial inflammation and oxidative stress were further significantly ameliorated in group HRD evidenced by the figure of biomarkers compared with group LRD (all P<0.05). Conclusions Resolvin D1 can improve post-resuscitation myocardial dysfunction in a dose-dependent manner in swine, and the mechanism is related to the inhibition of inflammation and oxidative stress. Key words: Cardiac arrest; Cardiopulmonary resuscitation; Myocardial dysfunction; Cardiac injury; Resolvin D1; Inflammation; Oxidative stress; Swine

The effects of resolvin D1 on brain injury after cardiopulmonary resuscitation in swine and its potential mechanisms

Objective To explore the role of resolvin D1 in reducing brain injury after porcine cardiopulmonary resuscitation and its potential mechanisms. Methods Twenty-eight male domestic pigs weighing (36±3)kg were utilized. The animals were randomly divided into 4 groups (n=7 each): sham operation group (group S), cardiopulmonary resuscitation group (group CPR), low-dose resolvin D1 group (group LRD), and high-dose resolvin D1 group (group HRD). The animals in group S only got the general preparation without the procedure of cardiac arrest and resuscitation. The pig model was established by 8 mins of untreated ventricular fibrillation and then 5 mins of cardiopulmonary resuscitation. At 5 min post-resuscitation, the doses of resolvin D1 0.3 μg/kg, and 0.6 μg/kg were correspondingly injected via the femoral vein in LRD and HRD groups, and meanwhile the same amount of vehicle was given into the animals in the other two groups. At 3 h, 6 h and 24 h post-resuscitation, the concentrations of neuron specific enolase (NSE) and S100B protein (S100B) in serum was measured. At 24 h post-resuscitation, neurological deficit score (NDS) was evaluated; thereafter the pigs were sacrificed, and cerebral cortex was obtained for the determination of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and malondialdehyde (MDA) contents, and superoxide dismutase (SOD) activity. Results Compared to group S, post-resusci-tation brain injury was observed in the other three groups, which was indicated by significantly increased NDS score, and markedly elevated concentrations of serum NSE and S100B. Compared to group CPR, the NDS was significantly decreased at 24 h post-resuscitation, and the concentrations of serum NSE and S100B were significantly reduced at 6 h and 24 h post-resuscitation in LRD and HRD groups. Compared to group LRD, the NDS score and its serum markers were further significantly decreased in group HRD. The inflammatory response and oxidative stress in brain tissue were observed in all the animals experiencing cardiac arrest and resuscitation, which were indicated by increased contents of TNF-α, IL-6 and MDA and decreased SOD activity. Compared to group CPR, the contents of TNF-α, IL-6 and MDA were significantly decreased while SOD activity was significantly increased in LRD and HRD groups. The indicators of inflammatory response and oxidative stress in brain tissue were further significantly improved in group HRD when compared to group LRD. Conclusions Resolvin D1 can reduce post-resuscitation brain injury in a dose-dependent manner in swine, and the mechanism is related to the inhibition of inflammatory response and oxidative stress. Key words: Fatty acids, unsaturated; Cardiopulmonary resuscitation/AE; Brain injuries/ET; Swine

Resolvin D1 Protects Lipopolysaccharide-induced Acute Kidney Injury by Down-regulating Nuclear Factor-kappa B Signal and Inhibiting Apoptosis.

Background:Resolvin D1 (RvD1) is a newly found anti-inflammatory bioactive compound derived from polyunsaturated fatty acids. The current study aimed to explore the protective effect of RvD1 on lipopolysaccharide (LPS)-induced acute kidney injury (AKI) and its possible mechanism.Methods:Both in vivo and in vitro studies were conducted. Male BALB/c mice were randomly divided into control group (saline), LPS group (LPS 5 mg/kg), RvD1 group (RvD1 5 μg/kg + LPS 5 mg/kg), and blockage group (Boc-MLP 5 μg/kg + RvD1 5 μg/kg + LPS 5 mg/kg). Boc-MLP is a RvD1 receptor blocker. The mice were intraperitoneally injected with these drugs and recorded for general condition for 48 h, while the blood and kidneys were harvested at 2, 6, 12, 24, and 48 h time points, respectively (n = 6 in each group at each time point). Human proximal tubule epithelial cells (HK-2) were randomly divided into control group (medium only), LPS group (LPS 5 μg/ml), RvD1 group (RvD1 10 ng/ml + LPS 5 μg/ml), and blockage group (Boc-MLP 10 ng/ml + RvD1 10 ng/ml + LPS 5 μg/ml). The cells were harvested for RNA at 2, 4, 6, 12, and 24 h time points, respectively (n = 6 in each group at each time point). Blood creatinine was tested by using an Abbott i-STAT portable blood gas analyzer. Tumor necrosis factor-α (TNF-α) level was detected by ELISA. Kidney pathology was observed under hematoxylin and eosin (HE) staining and transmission electron microscope (TEM). We hired immune-histological staining, Western blotting, and fluorescence quantitative polymerase chain reaction to detect the expression of RvD1 receptor ALX, nuclear factor-kappa B (NF-κB) signaling pathway as well as caspase-3. Kidney apoptosis was evaluated by TUNEL staining.Results:RvD1 receptor ALX was detected on renal tubular epithelials. Kaplan–Meier analysis indicated that RvD1 improved 48 h animal survival (80%) compared with LPS group (40%) and RvD1 blockage group (60%), while RvD1 also ameliorated kidney pathological injury in HE staining and TEM scan. After LPS stimulation, the mRNA expression of toll-like receptor 4, myeloid differentiation factor 88, and TNF-α in both mice kidneys and HK-2 cells were all up-regulated, while RvD1 substantially inhibited the up-regulation of these genes. Western blotting showed that the phosphorylated-IκB/IκB ratio in LPS group was significantly higher than that in the control group, which was inhibited in the RvD1 group. RvD1 could inhibit the up-regulation of cleaved-caspase-3 protein stimulated by LPS, which was prohibited in RvD1 blockage group. RvD1 group also had a lower proportion of apoptotic nuclei in mice kidney by TUNEL staining compared with LPS group.Conclusion:In LPS-induced AKI, RvD1 could decrease TNF-α level, ameliorate kidney pathological injury, protect kidney function, and improve animal survival by down-regulating NF-κB inflammatory signal as well as inhibiting renal cell apoptosis.

Resolvin D1 protects against hepatic ischemia/reperfusion injury in rats

ObjectiveInflammatory responses play an important role in the tissue damage during hepatic ischemia/reperfusion (I/R). Some resolvins have been shown to have protective properties in reducing I/R injury in the heart and kidney. The aim of the study was to investigate the effects of resolvin D1 (RvD1) on hepatic I/R. MethodsPartial warm ischemia was produced in the left and middle hepatic lobes of Sprague–Dawley rats for 60min, followed by 6h of reperfusion. Rats received either RvD1 (5μg/kg) or vehicle by intravenous injection prior to ischemia. On the basis of treatment with RvD1, some rats further received the PI3K inhibitor LY294002. Blood and tissue samples from the groups were collected after 6-h reperfusion. ResultsOur results indicate that the RvD1 receptor ALX/FPR2 is present in liver, and that pretreatment with RvD1 prior to I/R insult significantly blunted I/R-induced elevations of alanine aminotransferase (AST) and aspartate aminotransferase (ALT), and significantly improved the histological status of the liver. Moreover, RvD1 significantly inhibited inflammatory cascades, as demonstrated by attenuations of IL-6, TNF-α and myeloperoxidase levels. Reduced apoptosis, and increased phosphorylation of Akt, were observed in the RvD1 group compared with the control I/R group. These effects of RvD1 on hepatic I/R injury were diminished by the PI3K inhibitor. ConclusionsAdministration of RvD1 prior to hepatic I/R attenuates hepatic injury, at least in part through inhibition of inflammatory response and enhancement of phosphorylation of Akt.

Effect of resolvin D1 on focal cerebral ischemia-reperfusion injury in rats

Objective To evaluate the effect of resolvin D1 on focal cerebral ischemia-reperfusion (I/R) injury in rats. Methods One hundred and twenty adult male Sprague-Dawley rats, aged 7 weeks, weighing 260-280 g, were randomly divided into 5 groups (n=24 each) using a random number table: sham operation group (group S) , group I/R, low-dose resolvin D1 group (group LRD) , medium-dose resolvin D1 group (group MRD) , and high-dose resolvin D1 group (group HRD) . Focal cerebral I/R was induced by right middle cerebral artery occlusion using a nylon thread inserted into internal carotid artery and advanced cranially until resistance was met.The occlusion was maintained for 2 h followed by 24 h reperfusion.In LRD, MRD and HRD groups, 0.03, 0.10, 0.30 nmol resolvin D1 5 μl was injected into the lateral cerebral ventricle at the beginning of reperfusion, respectively.Neurological deficits were evaluated at 24 h of reperfusion and scored.The rats were then sacrificed, and their brains were removed for determination of infarct volume (by TTC staining) , cerebral water content, Evans blue content and expression of matrix metalloproteinase-9 (MMP-9) in the ischemic cortex. Results Compared with group S, the neurological deficit scores, cerebral infarct volume, and cerebral water and Evans blue content were significantly increased, and the expression of MMP-9 was up-regulated in the other 4 groups.Compared with group I/R, the neurological deficit scores, cerebral infarct volume, and cerebral water and Evans blue content were significantly decreased, and the expression of MMP-9 was down-regulated in group MRD and group HRD, and no significant change was found in the parameters mentioned above in group LRD. Conclusion Resolvin D1 can attenuate focal cerebral I/R injury in rats, and down-regulation of MMP-9 expression and decrease in permeability of blood-brain barrier may be involved in the mechanism. Key words: Docosahexaenoic acids; Reperfusion injury; Cerebral

Resolvin D1 attenuates lipopolysaccharide induced acute lung injury through CXCL-12/CXCR4 pathway

BackgroundThe recruitment of neutrophils plays an important role in the progress of acute lung injury (ALI). Excessive neutrophils released from bone marrow accumulate in lung, release proinflammatory factors, and cause tissue damage. CXCL-12/CXCR4 is an important signaling pathway, which regulates the migration of bone marrow hematopoietic cells out of bone marrow and involves in neutrophil accumulation and retention in the inflammatory site. Resolvin D1 (RvD1) is a kind of lipid mediators, which can alleviate many inflammatory diseases. We hypothesized that RvD1 can alleviate lipopolysaccharide (LPS)-induced ALI through regulating CXCL-12/CXCR4 pathway. MethodsWe randomized mice into five groups: control group, RvD1 group, LPS group, LPS plus RvD1 group, and LPS plus AMD3100 group. ALI was established by intratracheal instillation of LPS. After 24 and 72 h, mice were sacrificed, and lung tissues were harvested for histologic analysis, wet-to-dry ratio, myeloperoxidase activity, and CXCL-12 expression. Bronchoalveolar fluid was collected for protein analysis, cytokines assay, and flow cytometry analysis. ResultsHistologic findings as well as wet-to-dry ratio, protein concentration, cytokines assay, neutrophil number, and myeloperoxidase activity confirmed that RvD1 and AMD3100 alleviated LPS-induced ALI. RvD1 decreased CXCL-12 messenger RNA expression in lung. However, RvD1 promoted CXCR4 expression in neutrophils in the initial stage of inflammation and reduced its level in the later stage. ConclusionsRvD1 protects LPS-induced ALI partially through regulating CXCL-12/CXCR4 pathway.

Resolvin D1 improves survival in experimental sepsis through reducing bacterial load and preventing excessive activation of inflammatory response

Sepsis is characterized as an uncontrolled inflammatory response. Spite et al. (Nature 461(7268):1287-1291, 2009) had demonstrated that resolvin D2, which is derived from docosahexaenoic acid (DHA), improves survival in cecal ligation and puncture (CLP)-initiated sepsis and enhances bacterial clearance without immune suppression. Resolvin D1, which is also derived from DHA and homologous with resolvin D2, is an endogenous anti-inflammatory and proresolving lipid molecule. We sought to investigate the effects of resolvin D1 on sepsis and to explore the mechanism of action. Six-to-eight-week-old male C57BL/6 mice were randomly divided into three groups: the sham group underwent the sham operation followed by tail vein injection of vehicle (0.1 % ethanol); the CLP group received vehicle (0.1 % ethanol) after CLP; the resolvin D1 group received resolvin D1 (100 ng) after CLP. Blood, peritoneal lavage fluid, and organs of mice were harvested 24 h after treatment for cytokine analysis, cell counts, bacterial cultures, histopathological studies, and apoptosis quantification. Compared with the vehicle control group, the survival rate and bacterial clearance of mice with sepsis induced by CLP were improved after resolvin D1 treatment, but the numbers of neutrophils in peritoneal lavage fluid, the inflammatory cytokines, the phosphorylation of the nuclear factor-κB (NF-κB) (P65) pathway, and the apoptosis rate of CD3(+) T lymphocytes of the thymus were suppressed. Resolvin D1 treatment improved survival in mice with sepsis induced by CLP, enhanced organism bacterial clearance, suppressed the increase of the numbers of neutrophils in peritoneal lavage fluid, reduced the release of inflammatory cytokines, and decreased the apoptosis rate of CD3(+) T lymphocytes of the thymus. These results suggest that resolvin D1 may attenuate the degree of inflammatory reaction in sepsis caused by CLP, without harming the host defense response.