Assessment of Th17/Treg cells and Th cytokines in an improved immune thrombocytopenia mouse model.

OBJECTIVES: The improved passive immune thrombocytopenia (ITP) mouse model has been extensively utilized for the study of ITP. However, how closely this model matches the human inflammation state and immune background is unclear. Our study aimed to explore the profile of Th cytokines and Th17/Treg cells in the model. METHODS: We induced the ITP mouse model by dose-escalation injection of MWReg30. The serum levels of cytokines (IFN-γ, IL-2, IL-4, IL-10, IL-17A, and TGF-ß1) were measured by enzyme-linked immunosorbent assay and the frequency of Th17 and Treg cells was measured by flow cytometry. The mRNA expression of Foxp3 and RORrt was measured by real-time PCR. RESULTS: The serum levels of cytokines IFN-γ, TGF-ß1, IL-4, and IL-10 were significantly lower in ITP mice. The secretion of serum proinflammatory cytokines IL-2 and IL-17A and the percentage of Th17 cells showed no statistically significant increase. In ITP mice the frequency of Treg cells and mRNA expression of Foxp3 was significantly lower in splenocytes. CONCLUSION: Our data suggest that the improved passive ITP mouse model does not mimic the autoimmune inflammatory process of human ITP. Compared with human ITP, this model has a similar change in frequency of Treg cells, which may directly or indirectly result from antibody-mediated platelet destruction due to attenuated release of TGF-ß.

Strains of Group B streptococci from septic patients induce platelet activation via Toll-like Receptor 2.

Group B Streptococcus (GBS) causes life-threatening bacterial sepsis, especially in newborns and pregnant women. Patients suffering from sepsis often display low platelet counts, characterized by thrombocytopenia, because of platelet activation. In the present study, the roles of six GBS strains from septic patients in platelet aggregation, as well as the underlying mechanisms, were investigated. Incubation of platelets with three of the strains induced platelet aggregation, increased the secretion of cellular adhesin molecule CD62P and activation of GPIIb/IIIa. Furthermore, the GBS strains that induced platelet activation also caused an increase in the expression of Toll-like receptor (TLR) 2 in platelets. Pre-incubation of platelets with anti-TLR2 monoclonal antibody, but not anti-TLR4 monoclonal antibody, inhibited these functional responses induced by GBS. TLR2 stimulation also activated the phosphoinositide 3-kinase (PI3-K)/Akt signalling pathway in platelets, and inhibition of PI3-K significantly reduced GBS-induced platelet responses. Our results indicate that three of the GBS strains from the septic patients can trigger platelet activation by interacting with platelets, which involves the elevation of platelet TLR2 expression.

[Role of Treg Cells in Pathogensis of Mouse ITP].

OBJECTIVE: To explore the role of Treg cells in the pathogenesis of idiopathic thrombocytopenic purpura (ITP). METHODS: The ITP mouse model was established, the Treg cell ratio in peripheral blood and spleen was detected by flow cytometry, the CD4+ CD25+ T cells were sorted by immunomagnetic beads, the Treg cell associated transcription factors (Foxp3, Smad7, STAT5 and Akt-1) and cytokines (IL-10, TGF-ß) in CD4+ CD25+ T cells were enriched from spleen mononuclear cells, and the mRNA expression of Treg cell was measured by real-time PCR. RESULTS: The ratio of Tregs in peripheral blood and spleen decreased significantly in ITP mouse, as compared with the controls (P<0.01). In addition, the mRNA expression of IL-10, TGF-ß and Foxp3 decreased significantly in spleen CD4+ CD25+ T cells (P<0.05). Expression of Smad 7 mRNA was higher than that of controls. CONCLUSION: The alteration in Treg frequency and function may be responsible for the immune dysfunction in ITP disease. It is also speculated that the lower mRNA expression of Foxp3 and higher mRNA expression of Smad 7 may inhibit the proliferation and differentiation of Treg cells.

LPS preconditioning ameliorates intestinal injury in a rat model of hemorrhagic shock.

OBJECTIVE AND DESIGN: Previous studies indicate that endotoxin preconditioning may decrease the inflammatory response and alleviate intestinal mucosal damage caused by sepsis. However, it is not known whether preconditioning with endotoxin might protect the intestinal mucosa after hemorrhagic shock. In this study, we investigated the effect of lipopolysaccharide (LPS) preconditioning on the intestinal mucosa following hemorrhagic shock in a rat model. Given that intestinal toll-like receptor 4 (TLR4) signaling is exaggerated in response to LPS, we further investigated the role of TLR4 signaling in endotoxin tolerance. METHODS: Animals were pre-treated with intra-peritoneal Escherichia coli LPS for 5 days prior to hemorrhagic shock. Animals were bled to achieve a mean arterial pressure (MAP) of 35-40 mmHg, then resuscitated with Ringer solution and the heparinized shed blood to maintain MAP between 90 and 100 mmHg. The distal ileum was harvested after resuscitation and graded for mucosal damage. TNF-α, TLR4, cleaved caspase-3, and intestinal trefoil factor 3 (TFF3) levels were measured at different time points. RESULTS: Pretreatment with LPS significantly reduced intestinal mucosal damage and protein levels of cleaved caspase-3. Furthermore, animals pre-treated with LPS experienced reduction of TNF-α and increased mucosal expression of TFF3. LPS tolerance was associated with reduced TLR4 expression. CONCLUSIONS: Endotoxin preconditioning can lessen the effects of ischemia and reperfusion injury in intestinal mucosa of a rat model with hemorrhagic shock. It is hypothesized that this effect is mediated via inhibition of TLR4 over-expression.

Repair of damaged intestinal mucosa in a mouse model of sepsis.

BACKGROUND: The intestine is not only the main target attacked by sepsis but also the vital organ which mediated sepsis. The recovery of the damaged intestinal barrier structure and function is related to the occurrence and outcome of multiple organ dysfunction syndrome (MODS). How to protect and reduce the damage of the intestinal mucosa and how to promote the reconstruction of the intestinal mucosa have been the important topics in sepsis for many years. This study aimed to investigate the influential factors of intestinal mucosal reconstruction after intestinal epithelial injury in vivo in a mouse model of sepsis. METHODS: Mice were subjected to cecal ligation and puncture (CLP) for induction of sepsis to assess intestinal mucosal damage, epithelial cell apoptosis, and transformed number of goblet cells, and to detect the concentration of TNF-α, IL-1 and TGF-ß1 and TFF3 (trefoil factor 3) expression in the small intestinal mucosa. All above were performed by HE staining, western blot, ELISA and immunohistochemistry respectively. The experimental animals were divided into a sepsis group and a sham-operation group. The animals with sepsis were separately killed at 6 (7 animals), 24 (7 animals) and 48 hours (7 animals) after CLP. RESULTS: Injured intestinal mucosa was observed in the 3 groups under a light microscope, in which damage scores in the 24-hour and 48-hour groups were higher than in the 6-hour group and no difference was found between the two groups. Moreover, less of goblet cells or other epithelial cells adjacent to the injured surface migrated into the wound to cover the denuded area. The number of goblet cells was substantially decreased in the three CLP groups compared with the sham-operation group. Protein levels of IL-1 and TNF-α were significantly increased by 3-4 fold at all time points when compared with the sham-operation group, and cleaved caspase-3 by 4 fold. Although TFF3 expression was modestly increased for 6 hours after the onset of CLP, it appeared to decline at 24 hours and 48 hours as shown by Western blot. A similar tendency was observed upon TGF-ß1, i.e. the protein level was not elevated at 24 hours and 48 hours, but increased modestly at 6 hours. CONCLUSIONS: Sepsis from CLP shows less restitution on the surface of injured intestinal mucosa. There is evidence that both constant inflammatory reaction and epithelial cell apoptosis may affect mucosal reestablishment of the intestine at the onset of sepsis. Mucosa after severe sepsis showed the state of high inflammation, and declined goblet cell function and mucosal reconstruction, which affected the repair of damaged intestinal barrier. Constant inflammatory reaction, and declined goblet cell function and mucosal reconstruction ability may affect the reestablishment of intestinal mucosa at the onset of sepsis.

[Analysis of CD4(+)CD25(+)CD127(low/-) Treg cells in mice].

The quantitative identification and enrichment of viable regulatory T cells (Treg) requires reliable surface markers that are selectively expressed on Treg. Foxp3 is the accepted marker of natural Treg, but it cannot be used to isolate cells for functional studies. CD127 is a new surface marker expressed in Treg cells. In this study, two populations of Treg, including CD4(+)CD25(+)CD127(low/-) and CD4(+)CD25(+)Foxp3(+)T cells, and profiles of the Foxp3 expression in CD4(+)CD25(+)CD127(low/-) cells were compared to evaluate which population is better. The peripheral blood cells were collected and spleen suspension of BALB/C mice were prepared, and using triple staining CD4, CD25, CD127 and CD4, CD25, Foxp3. The profiles of Treg, including CD4(+)CD25(+)CD127(low/-) and CD4(+)CD25(+)Foxp3(+) were detected by flow cytometry. The quadruple staining CD4, CD25, Foxp3 and CD127 were used to determine the CD127 expression in CD4(+)CD25(+)Foxp3(+) cells. The results showed that on T cell subset the median expression levels of CD4(+), CD4(+)CD25(+) were 39.02%, 5.35% in peripheral blood and 23.49%, 3.86% in spleen. On CD4(+) T cell subset, the median expression level of CD4(+)CD25(+)CD127(low/-) and CD4(+)CD25(+)Foxp3(+)T cells were 7.13%, 3.97% in peripheral blood and 12.8%, 8.23% in spleen. The ratio of CD4(+)CD25(+)CD127(low/-) T cells was higher than that of CD4(+)CD25(+)Foxp3(+) cells in both peripheral blood and spleen cells (P < 0.01). The CD4(+)CD25(+)CD127(low/-) cells highly expressed Foxp3, while the CD4(+)CD25(+)Foxp3(+)T cells lowly expressed CD127. It is concluded that compared with the CD4(+)CD25(+)Foxp3(+) populations, CD4(+)CD25(+)CD127(low/-) T cells better fit the definition of naturally occurring regulatory T cells in peripheral blood cells and spleen of BALB/C mice. CD127(low/-) is a characteristic marker on surface of CD4(+)CD25(+) Treg cells, and has been confirmed to be more specific marker for quantitatively sorting Treg cells.

Mineralocorticoid receptor antagonism and aldosterone synthesis inhibition do not improve glomerulosclerosis and renal interstitial fibrosis in a model of chronic kidney allograft injury.

Chronic allograft injury (CAI) is a major cause of late graft failure with a multifactorial pathogenesis; however, in different experiments an inhibition of the renin-angiotensin system by angiotensin-converting enzyme inhibitors and angiotensin II type 1 receptor blockers ameliorated the progression of chronic renal disease. Different concepts supposed that aldosterone is involved in development and/or progression of renal diseases via interaction with a non-epithelial mineralocorticoid receptor (MR), e.g. reducing neointima formation. Our examinations therefore targeted on the effects of the aldosterone synthase inhibitor fadrozole and the MR antagonist spironolactone compared to vehicle in an established rat model of CAI. In our model of CAI, neither the aldosterone biosynthesis inhibitor nor a direct MR blockade had a positive effect on renal CAI in rats. Fadrozole- and spironolactone-treated animals demonstrated a higher proteinuria value, pathologically elevated potassium values, higher tubulointerstitial damage and markedly increased heart weight/body weight as compared to vehicle. Our observations also suggest that inhibition of the MR or the biosynthesis itself had a bad influence on the amount of sclerotic glomeruli and tubulointerstitial damage. The positive effects of inhibition of aldosterone as described in cardiac models could not yet be detected in kidney recipients.

Changes of the immunological barrier of intestinal mucosa in rats with sepsis.

BACKGROUND: Sepsis has become the greatest threat to in-patients, with a mortality of over 25%. The dysfunction of gut barrier, especially the immunological barrier, plays an important role in the development of sepsis. This dysfunction occurs after surgery, but the magnitude of change does not differentiate patients with sepsis from those without sepsis. Increased intestinal permeability before surgery is of no value in predicating sepsis. The present study aimed to observe the changes of intestinal mucosal immunologic barrier in rat models of sepsis induced by cecal ligation and puncture. METHODS: Sixty Sprague-Dawley rats were randomly divided into a sepsis group (n=45) and a control group (n=15). The rats in the sepsis group were subjected to cecal ligation and puncture (CLP), whereas the rats in the control group underwent a sham operation. The ileac mucosa and segments were harvested 3, 6 and 12 hours after CLP, and blood samples were collected. Pathological changes, protein levels of defensin-5 (RD-5) and trefoil factor-3 (TFF3) mRNA, and lymphocytes apoptosis in the intestinal mucosa were determined. In an additional experiment, the gut-origin bacterial DNA in blood was detected. RESULTS: The intestinal mucosa showed marked injury with loss of ileal villi, desquamation of epithelium, detachment of lamina propria, hemorrhage and ulceration in the sepsis group. The expression of TFF3 mRNA and level of RD-5 protein were decreased and the apoptosis of mucosal lymphocyte increased (P<0.05) in the sepsis group compared with the control group. Significant differences were observed in RD-5 and TFF3 mRNA 3 hours after CLP and they were progressively increased 6 and 12 hours after CLP in the sepsis group compared with the control group (P<0.05, RD-5 F=11.76, TFF3 F=16.86 and apoptosis F=122.52). In addition, the gut-origin bacterial DNA detected in plasma was positive in the sepsis group. CONCLUSION: The immunological function of the intestinal mucosa was impaired in septic rats and further deteriorated in the course of sepsis.

[Toll-like receptor 4 expression mediates the activation of platelets induced by LPS].

The study was aimed to investigate the expression of Toll-like receptor 4 (TLR4) on platelets and to determine whether platelet TLR4 involves in its activation induced by lipopolysaccharide (LPS). Human platelet-rich plasma (PRP) and platelet suspension obtained from 15 healthy individuals pretreated with a concentration of 0.2 microg/ml of LPS in the presence or absence of thrombin (1 U/ml) for 1 hour. The expressions of TLR4, CD62P (P-select) and CD40L on platelets were detected by flow cytometry, and platelet TLR4 expression was further determined by Western blot analysis. The results indicated that the percentage of TLR4-positive platelets induced by thrombin was increased by 32.34% compared with the resting platelets (25.44%, p < 0.05). TLR4 expression on platelets treated with LPS was remarkably elevated in the presence or absence of thrombin. However, the expression level of the former was much higher than that of the latter and thrombin stimulation alone (p < 0.05). Moreover, the similar results were found in Western blot analysis. Synchronously, expressions of CD62P and CD40L on resting platelets were 6.39% and 2.45%, they were also markedly increased when treated with thrombin (42.68% and 14.8%) and LPS respectively, and the increases of expression of CD62P and CD40L were more significant when stimulated with both LPS and thrombin (63.03% and 13.94%). Although anti-TLR4 antibody inhibited significantly the increase of TLR4, CD62P and CD40L on platelets induced by LPS, which did not affect their increase induced by thrombin. In conclusion, the evidence has been shown that functional TLR4 can be expressed on human platelets. It may involve in platelet activation as an important mediator of LPS-induced CD62P and CD40L expressions on platelets.

[Effect of ulinastatin on apoptosis in ileal mucosa of rats with hemorrhagic shock].

OBJECTIVE: To investigate the effect of ulinastatin on apoptosis in ileal mucosa of rats with hemorrhagic shock. METHODS: A prospective, controlled animal study was performed. The rat model of hemorrhagic shock was replicated according to method described by Chaudry. After 60 minutes period of bleeding, rats were resuscitated by transfusion of shed blood and normal saline. A part of the animals were additionally treated with ulinastatin. The expression of tumor necrosis factor-alpha (TNF-alpha), malondialdehyde (MDA) content in serum, and expression of Bax, Bcl-2, caspase 3 protein in ileal mucosa were determined at different time points after reperfusion. RESULTS: Compared with the normal saline group, the expression levels of TNF-alpha, MDA content in serum, Bax and caspase 3 protein in ileal mucosa during hemorrhagic shock after resuscitation were significantly increased, while Bcl-2 protein was markedly decreased. After fluid resuscitation, obvious increase in MDA, Bcl-2 protein, significant decrease in the level of TNF-alpha, the expression of Bax and caspase 3 protein in ileal mucosa were observed in the ulinastatin group compared with normal saline group. CONCLUSION: Ulinastatin has protective effect on rats with hemorrhagic shock by suppressing the apoptosis in ileal mucosa.

[Effect of goblet cell in rat intestine on the restitution process of the gut barrier after hemorrhagic shock].

OBJECTIVE: To investigate the changes of the goblet cells in the intestine during the restitution process of the gut barrier after hemorrhagic shock. METHODS: Forty-nine Sprague-Dawley rats with body weight of 250-300 g were divided into control group (n=7) and experimental group (n=42). Rats in the experimental group was further divided into 6 groups (n=7 each) according to different time point at 1, 3, 6, 12, 24, and 36 hours after hemorrhagic shock resuscitation. The specimens from ileum tissue were taken to observe the morphological chan ges of the intestinal mucosa. The number of goblet cells was determined by light microscope and/or electron microscope. The contents of trefoil factor family 3 (TFF3) of goblet cells were examined using GC-9A gas chromatographic instrument. RESULTS: After hemorrhagic shock, mucosal epithelial injury was obvious in the small intestine. Tissue restitution was found after 3 hours, and mostly established after 12 hours. Following tissue restitution,the denuded mucosal surface was covered intensively by goblet cells. The number of goblet cells on the intestinal mucosa was reduced significantly from 243+/- 13 at 1 h to 157+/- 9 at 24 h (r=- 0.910, P< 0.01), and returned to normal level at 36 h. In the experimental group, the content of TFF3 in the intestinal mucosa increased significantly at 12 hours, decreased, but was still higher at 24 hours (t=3.24, P< 0.05). CONCLUSIONS: The goblet cells play a key role in the restitution of intestinal mucosa. High expression of TFF3 may facilitate the intestinal mucosal restitution in the early phase.

Functional and morphological changes of the gut barrier during the restitution process after hemorrhagic shock.

AIM: To investigate the functional, morphological changes of the gut barrier during the restitution process after hemorrhagic shock, and the regional differences of the large intestine and small intestine in response to ischemia/reperfusion injury. METHODS: Forty-seven Sprague-Dawley rats with body weight of 250-300 g were divided into two groups: control group (sham shock n = 5) and experimental group (n = 42). Experimental group was further divided into six groups (n = 7 each) according to different time points after the hemorrhagic shock, including 0(th) h group, 1st h group, 3rd h group, 6th h group, 12th h group and 24th h group. All the rats were gavaged with 2 mL of suspension of lactulose (L) (100 mg/2 mL) and mannitol (M) (50 mg/each) at the beginning and then an experimental rat model of hemorrhagic shock was set up. The specimens from jejunum, ileum and colon tissues and the blood samples from the portal vein were taken at 0, 1, 3, 6, 12 and 24 h after shock resuscitation, respectively. The morphological changes of the intestinal mucosa, including the histology of intestinal mucosa, the thickness of mucosa, the height of villi, the index of mucosal damage and the numbers of goblet cells, were determined by light microscope and/or electron microscope. The concentrations of the bacterial endotoxin lipopolysaccharides (LPS) from the portal vein blood, which reflected the gut barrier function, were examined by using Limulus test. At the same time point, to evaluate intestinal permeability, all urine was collected and the concentrations of the metabolically inactive markers such as L and M in urine were measured by using GC-9A gas chromatographic instrument. RESULTS: After the hemorrhagic shock, the mucosal epithelial injury was obvious in small intestine even at the 0(th) h, and it became more serious at the 1st and the 3rd h. The tissue restitution was also found after 3 h, though the injury was still serious. Most of the injured mucosal restitution was established after 6 h and completed in 24 h. Two distinct models of cell death-apoptosis and necrosis-were involved in the destruction of rat intestinal epithelial cells. The number of goblet cells on intestinal mucosa was reduced significantly from 0 to 24 h (the number from 243+/-13 to 157+/-9 for ileum, 310+/-19 to 248+/-18 for colon; r = -0.910 and -0.437 respectively, all P<0.001), which was the same with the large intestine, but the grade of injury was lighter with the values of mucosal damage index in 3 h for jejunum, ileum, and colon being 2.8, 2.6, 1.2, respectively. The mucosal thickness and the height of villi in jejunum and ileum diminished in 1 h (the average height decreased from 309+/-24 to 204+/-23 microm and 271+/-31 to 231+/-28 microm, r = -0.758 and -0.659, all P<0.001; the thickness from 547+/-23 to 418+/-28 microm and 483+/-45 to 364+/-35 microm, r = -0.898 and -0.829, all P<0.001), but there was no statistical difference in the colon (F = 0.296, P = 0.934). Compared with control group, the urine L/M ratio and the blood LPS concentration in the experimental groups raised significantly, reaching the peak in 3-6 h (L/M: control vs 3 h vs 6 h was 0.029+/-0.09 vs 0.063+/-0.012 vs 0.078+/-0.021, r = -0.786, P<0.001; LPS: control vs 3 h vs 6 h was 0.09+/-0.021 vs 0.063+/-0.012 vs 0.25+/-0.023, r = -0.623, P<0.001), and it kept increasing in 24 h. CONCLUSION: The gut barrier of the rats was seriously damaged at the early phase of ischemic reperfusion injury after hemorrhagic shock, which included the injury and atrophy in intestinal mucosa and the increasing of intestinal permeability. Simultaneously, the intestinal mucosa also showed its great repairing potentiality, such as the improvement of the intestinal permeability and the recovery of the morphology at different phases after ischemic reperfusion injury. The restitution of gut barrier function was obviously slower than that of the morphology and there was no direct correlation between them. Compared with the small intestine, the large intestine had stronger potentiality against injury. The reduction of the amount of intestinal goblet cells by injury did not influence the ability of intestinal mucosal restitution at a certain extent and it appeared to be intimately involved in the restitution of the epithelium.

[Study on morphological change in intestinal mucosa from injury to repair after hemorrhagic shock].

OBJECTIVE: To study on morphological changes in mucosa of the small and large intestine mucosa after resuscitation of hemorrhagic shock. METHODS: The morphological changes in intestinal mucosa were observed under light and electron microscope, including the histology of intestinal mucosa, determination of height of villi and evaluation of mucosa damage index in the different phases after traumatic-hemorrhagic shock. RESULTS: Mucosa epithelial injury was obvious in small intestine were even at 0 hour, becoming more serious in 1 hour up to 3 hours. The tissue repair began after 3 hours, though the injury was still serious. Most of the inJured mucosa began to repair after 6 hours, and completed in 24 hours. The condition of the large intestine was similar to that of the small intestine, but the injury was less severe. The mucosal thickness and the height of villi were diminished after 1 hour of shock, but there was no obvious change in the colon. CONCLUSION: In the early phase after hemorrhagic shock, intestinal mucosal barrier are subJected to damage, but it could repair and recover in a short time. Compare with small intestine, large intestine have stronger potentiality against injury.