Hepatic vagotomy blunts liver regeneration after hepatectomy by downregulating the expression of interleukin-22

BACKGROUND Rapid regeneration of the residual liver is one of the key determinants of successful partial hepatectomy(PHx).At present,there is a lack of recognized safe,effective,and stable drugs to promote liver regeneration.It has been reported that vagus nerve signaling is beneficial to liver regeneration,but the potential mechanism at play here is not fully understood.AIM To explore the effect and mechanism of hepatic vagus nerve in liver regeneration after PHx.METHODS A PHx plus hepatic vagotomy(Hv)mouse model was established.The effect of Hv on liver regeneration after PHx was determined by comparing the liver regeneration levels of the PHx-Hv group and the PHx-sham group mice.In order to further investigate the role of interleukin(IL)-22 in liver regeneration inhibition mediated by Hv,the levels of IL-22 in the PHx-Hv group and the PHx-sham group was measured.The degree of liver injury in the PHx-Hv group and the PHx-sham group mice was detected to determine the role of the hepatic vagus nerve in liver injury after PHx.RESULTS Compared to control-group mice,Hv mice showed severe liver injury and weakened liver regeneration after PHx.Further research found that Hv downregulates the production of IL-22 induced by PHx and blocks activation of the signal transducer and activator of transcription 3(STAT3)pathway then reduces the expression of various mitogenic and anti-apoptotic proteins after PHx.Exogenous IL-22 reverses the inhibition of liver regeneration induced by Hv and alleviates liver injury,while treatment with IL-22 binding protein(an inhibitor of IL-22 signaling)reduce the concentration of IL-22 induced by PHx,inhibits the activation of the STAT3 signaling pathway in the liver after PHx,thereby hindering liver regeneration and aggravating liver injury in PHx-sham mice.CONCLUSION Hv attenuates liver regeneration after hepatectomy,and the mechanism may be related to the fact that Hv downregulates the production of IL-22,then blocks activation of the STAT3 pathway.

Expression of interleukin-22/STAT3 signaling pathway in ulcerative colitis and related carcinogenesis

AIM:To investigate the expression of interleukin (IL)-22 and its related proteins in biopsy specimens from patients with ulcerative colitis (UC) and UC-related carcinogenesis. METHODS:Biopsy specimens were obtained from patients with inactive (n = 10), mild-to-moderately active (n = 30), severely active (n = 34), initial (n = 30), and chronic UC (n = 44), as well as UC patients with dysplasia (n = 10). Specimens from patients without colonic abnormalities (n = 20) served as controls. Chronic colitis in experimental mice was induced by 2.5% dextran sodium sulfate. The expression levels of IL-22, IL-23, IL-22R1 and phosphorylated STAT3 (p- STAT3) were determined by immunohistochemistry. Bcl-2, cyclin D1 and survivin expression was detected by Western blotting. RESULTS:Patients with active UC had significantly more IL-22, IL-23, IL-22R1 and p-STAT3-positive cells than the patients with inactive UC and normal controls. Furthermore, IL-22 and related proteins were closely related to the severity of the colitis. The expression of IL-22 and IL-22R1 in the tissue of initial UC was stronger than in that of chronic UC, whereas the expression of p-STAT3 was significantly increased in chronic UC tissues. In dysplasia tissues, the expression level of IL-22 and related proteins was higher compared with controls. Mouse colitis model showed that expression of IL-22, IL-22R1 and IL-23 was increased with time, p-STAT3 and the downstream gene were also remarkably upregulated.CONCLUSION:IL-22/STAT3 signaling pathway may be related to UC and UC-induced carcinogenesis and IL-22 can be used as a biomarker in judging the severity of UC.

Effects of Aprotinin on Serum Interleukin-2 and Soluble Interleukin-2 Receptor during Cardiopulmonary Bypass

Interleukin-2 and its receptor are of importance in regulating immunity responses. The changes of interleukin-2 (IL-2) and soluble interleukin-2 receptor (IL-2R) during heart valve (s) replacement operation and effects of aprotinin on them were observed. Twenty patients undergoing heart valve (s) replacement were randomly divided into two groups: control group (n=10) and apro- tinin group (n=10). In aprotinin group, 1 000 000 KIU aprotinin was given by vein injection and then 2 000 000 KIU was given as a bolus in prime. Blood samples were collected before CPB, right after CPB and on the 1st, 3rd and 7th postoperative day (POD) for serum IL-2 and sIL-2R determination. Results showed that after CPB, IL-2 was reduced and slL-2R increased. Meanwhile, serum IL-2R was lower in aprotinin group than that of control. It is concluded that the immunity depression after CPB is associated with low level of IL-2 and high level of sIL-2R and aprotinin can ameliorate the situation.

INTERLEUKIN-2 (IL-2) PRODUCTION AND INTERLEUKIN-2 RECEPTOR EXPRESSION IN PATIENTS WITH APLASTIC ANEMIA

IL-2 production and IL-2 receptor (Tac antigen) of the peripheral blood mononuclear cells in 30 patients with aplastic anemic (AA) were studied. We found that mononuclear cells from patients produce spontaneously IL-2 in the absence of exogenous lee-tin stimulation, the proportion of Tac+ cells in mononuclear cells increased. The release of IL-2 and or Tac antigen expression were elevated in almost every patient with AA. The plasma from patients stimulate mitogen-induced blastogenesis and Tac antigen expression of normal human lymphocytes. Immunological 1 abnormalities of patients with AA possibly might represents secondary response to bone marrow depression.

Changes in soluble interleukin-2 receptor level in serum and Na^+ -K^+ -exchanging ATPase activity in semen of infertile men caused by antisperm antibody

Aim: To explore the possible mechanisms of male infertility caused by antisperm antibody (AsAb). Methods: Thesoluble interleukin-2 receptor (sIL-2R) level in serum was analyzed by ELISA and Na^+ -K^+ -exchanging ATPase activi-ty in semen by phosphorus (Pi) assay. Results: The slL-2R level in serum was significantly higher and the Na^+ -K^+ -exchanging ATPase activity in semen significantly lower in AsAb positive infertile men when compared with thecontrols. Conclusion: The AsAb titer varies with the slL-2R level in serum. A decrease in Na^+ -K^+ -exchangingATPase activity in semen may play a role in male infertility caused by AsAb.

Porcine Interleukin-2 Expression in Insect Cells and Its Enhancement of Pig Immunity to Swine Influenza Virus Inactivated Vaccine

Mature porcine interleukin-2 （pIL-2） gene was amplified by PCR from the plasmid pGEM-T-pIL2 and cloned into the baculovirus pFastBacTM Dual vector of the Bac-to-Bac baculovirus expression system under the control of the PH promoter. Recombinant plL-2 （rpIL-2） expressed in Sf9 insect cells was detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunofluorescence assay. Western blot analysis confirmed that the rpIL-2 protein had a molecular mass of 20 kDa, which was larger than the molecular mass of the mature protein predicted based on its peptide sequence. The rpIL-2 protein induced in vitro proliferation of ConA-stimulated porcine splenocytes and enhanced in vivo protective immune responses induced by vaccinating the pigs with inactivated oil emulsion vaccine against swine influenza virus. The results showed that the rpIL-2 expressed in Sf9 insect cells has immunoenhancement effects; the finding lays the foundation for the preparation of a specific recombinant IL-2 protein and the development of a novel immune adjuvant of vaccines against various infectious porcine pathogens to increase the immunoprotective efficacy of vaccines.

PURGING OF BONE MARROWS CONTAMINATED WITH MYELOID LEUKEMIC CELLS BY INTERLEUKIN-2 AND LYMPHOKINE-ACTIVATED KILLER CELLS

The capability of recombinant human interleukin-2 ( rhIL-2) and lymphokine-activated killer (LAK) cells in the purging of normal human bone marrows contaminated with human myeloid leukemic cell lines was evaluated. Mixtures of normal human bone marrow mononuclear cells ( BMC) and K562 cells or HL-60 cells (at the BMCK562 ratio of 200:1, 100:1 or 20:1) were incubated with IL-2 with or without LAK cells at the BMC:LAK ratio of 1:1 for one or three days. The nubmers of residual K562 cells, BFU-E and CFU-GM were examined by clonogenic assays. In 200:1 mixture groups without LAK cells, the number of K562 colonies reduced by 50% with no loss of BFU-E and CFU-GM in one-day cultures, and no K562 colonies formed in three-day cultures with about 20% loss of BFU-E and CFU-GM. If the BMC.K562 ratios were 100:1 or 20:1 in the mktures, the leukemic cells could not be eliminated. When the mixtures were incubated with IL-2 and LAK cells, no leukemic cell colonies were detected in the 20:1 group following one-day

Fluence of Glucosidorum Tripterygii Totorum on joint and serum soluble interleukin-2 receptor in patients with ankylosing spondylitis

Objective The current study was designed to find out the effect of Glucosidorum Tripterygii Totorum (GTT) on the serum level of soluble interleukin-2 receptor (sIL-2R) in patient with ankylosing spondylitis (AS). Method 29 patients with active AS were selected to take GTT (1mg per kg) three times a day for one year. After that, its curative effect was evaluated. The serum level of sIL-2R of these patients was measured by sandwich ELISA method and was compared with that of normal subjects. Result The serum level of sIL-2R in active AS patients was obviously higher than that of the non-active AS patients. (P<0.01). The total effective rate of GTT on AS was 89.6%, while clinical relief rate 27.6%, obvious effective rate 44.8%, effective rate 17.2% and non-effective rate 10.4%. The patients’ serum level of sIL-2R after therapy was significantly lower than that before therapy except patients with no effect. (P<0.05). Conclusion GTT has positive curative effect on active AS patients and could cause obvious decrease of the serum level of sIL-2R. The serum level of sIL-2R can be used as an important index of activity of AS and as a guide of therapy.

Study of the Effect of Leeching on Plasma Endothelin and Soluble Interleukin-2 Receptor in Patients with Systemic Lupus Erythematosus

Objective: to explore the mechanism of leeching in treating systemic lupus erythematosus (SLE). Methods: Forty-four patients with SLE were randomly divided into conventional corticosteroid treated group (control group, n =20) and conventional treatment group with leeching intervention added (leeching group, n =24). Before and after treatment the concentration of plasma endothelin (ET) and soluble interleukin-2 receptor (sIL-2R) were determined. Results: Before treatment the level of plasma ET and sIL-2R in the SLE patients were all higher than those in the normal healthy group, ( P <0.01). But after treatment the level of these in both groups were significantly improved than those of before treatment ( P <0.05), and comparison between these two treated groups showed that the difference between them was significant ( P <0.05). Conclusion: Leeching added to conventional treatment of SLE could be more effective in improving the level of plasma ET and sIL-2R, and ameliorating the impairment of renal tissues.

Tumoricidal activation of murine resident peritoneal macrophages on pancreatic carcinoma by interleukin-2 and monoclonal antibodies

INTRODUCTIONMacrophages play an important role in tumor lysisand growth inhibition.They can be activated to atumoricidal state by a variety of agents such asIFNr,TNFα or IL2.The killing machanisms ofactivated macrophages have been extensivelyinvestigated.Recently,it has been proved thatantibody dependent cellular cytotoxicity (ADCC) isone of the potent arms to lyse tumor cells

Elevated pancreatic enzymes, IgM, soluble interleukin-2 receptor in anti-GADab(+) type 1 diabetes

Type 1 diabetes can be classified into immune-mediated diabetes (type 1A) and idiopathic diabetes, which lacks immunological evidence for beta cell autoimmunity (type 1B). Type 1A diabetes is characterized by the presence of the anti-glutamic acid decarboxylase antibody (anti-GADab). Fulminant type 1 diabetes is classified as type 1B diabetes, and characterized by the absence of anti-GADab, flu-like symptoms, and elevated serum exocrine pancreatic enzymes. We report a type 1 diabetic patient who showed flu-like symptoms, elevated serum exocrine pancreatic enzymes, and an extremely high-titer of anti-GADab, manifesting the characteristics of both type 1A and fulminant type 1 diabetes.

Effect of interleukin-2 on neurogliocyte and neuron apoptosis in rat models of acute spinal cord injury

BACKGROUND： lnterleukin-2 （IL-2） may influence the growth and survival of nerve cells following spinal cord injury and resuscitate the proliferation and maturation of oligodendrocytes. OBJECTIVE： To observe the effect of IL-2 on neuronal apoptosis of neurogliocytes at different times following acute spinal cord injury in rats. DESIGN, TIME AND SETTING： A randomized grouping trial based on cellular morphology was performed at the Institute of Traumatic Orthopedics of Shandong Province between October 2004 and January 2006. MATERIALS： A total of 72 adult, male, Sprague Dawley rats were included in this study and were divided into a control group and an IL-2 group. The Bcl-2 monoclonal antibody and TUNEL kit were purchased from Wunan Boster Biological Technology Corporation. METHODS： Spinal cord injury was induced in all the rats by dropping a weight from a height of 25 cm onto the exposed spinal cord at vertebral levels T7-11, thus producing a mild lesion. Immediately following the modeling, the rats were injected with daily IL-2 （10 uL） intramuscularly （the IL-2 group）. Other rats received an injection of physiological saline 0.5 mL/d （the control group）. MAIN OUTCOME MEASURES： Bcl-2 immunohistochemistry was applied to detect the Bcl-protein and positive cell expression. The TUNEL method was used to count the number of apoptotic cells. RESULTS： The expression level of Bcl-2 proteins increased significantly in spinal cord tissues during the first day after acute spinal cord injury, reaching a peak on days 3 and days 8 in the control and IL-2 groups, respectively. They were more prevalent in neurogliocytes than in neurocytes, and then began to decrease on day 14. From then until day 21, less expression was detected （P 〈 0.05）. In the control group, many apoptotic cells existed after 24 hours, and most of them were gliocytes; apoptotic cells reached a peak after 3-8 days. They then decreased gradually until day 21, when a small number of cells were still available. In the IL-2 group, the number of positive cells was significantly lower than in the control group （P 〈 0.05）. CONCLUSION： The expression of Bcl-2 and the number of apoptotic cells in neurogliocytes undergo similar changes with time after acute spinal cord injury. IL-2 may upregulate the expression of Bcl-2 proteins and decrease cell apoptosis in spinal cord tissue.

Sequence Analysis on Interleukin-2 Gene and Interleukin-6 Gene in a Hybrid Pig

[ Objective] To understand the functions of interteukin-2 （IL-2） and interleukin-6 （IL-6） in immune response. [ Method] Peripheral lymphocytas were isolated from a hybrid pig （ Duroc x Landrace x Shandong local pig） and stimulated with canavalin A in vitro. With total RNA as templates, the IL-2 and IL-6 cDNA were amplified by the RT-PCR and sequenced, respectively. [Result] The sequence of IL-2 gene had 100.0% nucleotide homology to the published IL-2 sequences. The sequence of IL-6 gene had 99.8% -100.0% nucleotide homology to the published IL-6 sequences, and the amino acid homology was 99.1% -100.0%. [ Conclusion] NO great variation of the IL-2 gene and IL-6 gene is observed in the hybdd pig, and these results provide a basis for research about functions of IL-2 and IL-6 protein.

Analysis of anti-zona pellucida antibody and tumor necrosis factor-α,γ-interferon and interleukin-2 in sera from patients with premature ovarian failure

Objective:To investigate the role and the clinical significance of anti-zona pellucidaantibody (AzpAb) and tumor necrosis factor-α(TNF-α),γ-interferon(IFN-γ) and inter-leukin-2 (IL-2) in sera from patients with premature ovarian failure (POF).Methods: The AzpAb in the serum of POF patient was analyzed by means ofELISA. The levels of TNF-α, IL-2 and IFN-γ in the serum were determined by meansof radioimmunoassay (RIA).Results:The level of serum AzpAb in the POF patients was significantly higher thanthat of the normal controls(P＜0.001). The levels of TNF-α and IL-2 were significantlyreduced (P＜0. 001), and the level of IFN-γ was significantly elevated (P＜0.01). Thelevels of above three cytokines in AzpAb positive group were significantly higher thanthose of the negative group in POF patients.Conclusion: This study suggested that AzpAb, TNF-α, IFN-γ and IL-2 might playimportant roles in the pathogenesis of autoimmune POF.

Interleukin-22 contributes to liver regeneration in micewith concanavalin A-induced hepatitis after hepatectomy

AIM: To investigate the therapeutic effects and mechanisms of interleukin(IL)-22 in liver regeneration in mice with concanavalin A(Con A)-induced liver injury following 70% hepatectomy.METHODS: Mice were injected intravenously with Con A at 10 μg/g body weight 4 d before 70% hepatectomy to create a hepatitis model, and recombinant IL-22 was injected at 0.125 μg/g body weight 30 min prior to 70% hepatectomy to create a therapy model. Control animals received an intravenous injection of an identical volume of normal saline.RESULTS: IL-22 treatment prior to 70% hepatectomy performed under general anesthesia resulted in reductions in the biochemical and histological evidence of liver injury, earlier proliferating cell nuclear antigen expression and accelerated recovery of liver mass. IL-22 pretreatment also significantly induced signal transducer and activator of transcription factor 3(STAT3) activation and increased the expression of a variety of mitogenic proteins, such as Cyclin D1. Furthermore, alpha fetal protein m RNA expression was significantly elevated after IL-22 treatment.CONCLUSION: In this study, we demonstrated that IL-22 is a survival factor for hepatocytes and prevents and repairs liver injury by enhancing pro-growth pathways via STAT3 activation. Treatment with IL-22 protein may represent a novel therapeutic strategy for preventing liver injury in patients with liver disease who have undergone hepatectomy.

Interleukin-22 receptor 1 is expressed in multinucleated giant cells:A study on intestinal tuberculosis and Crohn’s disease

BACKGROUND It is challenging to distinguish intestinal tuberculosis from Crohn’s disease due to dynamic changes in epidemiology and similar clinical characteristics. Recent studies have shown that polymorphisms in genes involved in the interleukin (IL)- 23/IL-17 axis may affect intestinal mucosal immunity by affecting the differentiation of Th17 cells. AIM To investigate the specific single-nucleotide polymorphisms (SNPs) in genes involved in the IL-23/IL-17 axis and possible pathways that affect susceptibility to intestinal tuberculosis and Crohn's disease. METHODS We analysed 133 patients with intestinal tuberculosis, 128 with Crohn’s disease, and 500 normal controls. DNA was extracted from paraffin-embedded specimens or whole blood. Four SNPs in the IL23/Th17 axis (IL22 rs2227473, IL1β rs1143627, TGFβ rs4803455, and IL17 rs8193036) were genotyped with TaqMan assays. The transcriptional activity levels of different genotypes of rs2227473 were detected by dual luciferase reporter gene assay. The expression of IL-22R1 in different intestinal diseases was detected by immunohistochemistry. RESULTS The A allele frequency of rs2227473 (P = 0.030, odds ratio = 0.60, 95% confidence interval: 0.37-0.95) showed an abnormal distribution between intestinal tuberculosis and healthy controls. The presence of the A allele was associated with a higher IL-22 transcriptional activity (P < 0.05). In addition, IL-22R1 was expressed in intestinal lymphoid tissues, especially under conditions of intestinal tuberculosis, and highly expressed in macrophage-derived Langhans giant cells. The results of immunohistochemistry showed that the expression of IL-22R1 in patients with Crohn's disease and intestinal tuberculosis was significantly higher than that in patients with intestinal polyps and colon cancer (P < 0.01). CONCLUSION High IL-22 expression seems to be a protective factor for intestinal tuberculosis. IL-22R1 is expressed in Langhans giant cells, suggesting that the IL-22/IL-22R1 system links adaptive and innate immunity.

Notch1 downregulation combined with interleukin-24 inhibits invasion and migration of hepatocellular carcinoma cells

AIM: To confirm the anti-invasion and anti-migration effects of down-regulation of Notch1 combined with interleukin(IL)-24 in hepatocellular carcinoma(HCC) cells.METHODS: γ-secretase inhibitors(GSIs) were used to down-regulate Notch1.Hep G2 and SMMC7721 cells were seeded in 96-well plates and treated with GSI-I or/and IL-24 for 48 h.Cell viability was measured by MTT assay.The cellular and nuclear morphology was observed under a fluorescence microscope.To further verify the apoptotic phenotype,cell cultures were also analyzed by flow cytometry with Annexin V-FITC/propidium iodide staining.The expression of Notch1,SNAIL1,SNAIL2,E-cadherin,IL-24,XIAP and VEGF was detected by Western blot.The invasion and migration capacities of HCC cells were detected by wound healing assays.Notch1 and Snail were downregulated by RNA interference,and the target proteins were analyzed by Western blot.To investigate the mechanism of apoptosis,we analyzed Hep G2 cells treated with si Notch1 or si CON plus IL-24 or not for 48h by caspase-3/7 activity luminescent assay.RESULTS: GSI-I at a dose of 2.5 μmol/L for 24 h caused a reduction in cell viability of about 38% in Hep G2 cells.The addition of 50 ng/m L IL-24 in combination with 1 or 2.5 μmol/L GSI-I reduced cell viability of about 30% and 15%,respectively.Treatment with IL-24 alone did not induce any cytotoxic effect.In SMMC7721 cells with the addition of IL-24 to GSI-I(2.5 μmol/L),the reduction of cell viability was only about 25%.Following GSI-I/IL-24 combined treatment for 6 h,the apoptotic rate of Hep G2 cells was 47.2%,while no significant effect was observed in cells treated with the compounds employed separately.Decreased expression of Notch1 and its associated proteins SNAIL1 and SNAIL2 was detected in Hep G2 cells.Increased E-cadherin protein expression was noted in the presence of IL-24 and GSI-I.Furthermore,the increased GSI-I and IL-24 in Hep G2 cell was associated with downregulation of MMP-2,XIAP and VEGF.In the absence of treatment,Hep G2 cells could migrate into the scratched space in 24 h.With IL-24 or GSI-I treatment,the wound was still open after 24 h.And the distance of the wound closure strongly correlated with the concentrations of IL-24 and GSI-I.Treatment of Notch-1 silenced Hep G2 cells with 50 ng/m L IL-24 alone for 48 h induced cytotoxic effects very similar to those observed in non-silenced cells treated with GSI-I/IL-24 combination.Caspase-3/7 activity was increased in the presence of si Notch1 plus IL-24 treatment.CONCLUSION: Down-regulation of Notch1 by GSI-I or si RNA combined with IL-24 can sensitize apoptosis and decrease the invasion and migration capabilities of Hep G2 cells.

Interleukin-21 triggers effector cell responses in the gut

In the gut of patients with Crohn's disease and patients with ulcerative colitis,the major forms of inflammatory bowel diseases(IBD) in humans,the tissue-damaging immune response is mediated by an active cross-talk between immune and non-immune cells.Accumulating evidence indicates also that cytokines produced by these cells play a major role in initiating and shaping this pathologic process.One such cytokine seems to be interleukin(IL)-21,a member of the common γ-chainreceptor family.IL-21 is produced in excess in the in-flamed intestine of patients with IBD mostly by activated CD4+ T helper cells co-expressing interferon-γ and follicular T helper cells.Moreover,both in vitro and in vivo studies indicate that excessive IL-21 production leads to the activation of multiple signaling pathways that expand and sustain the ongoing mucosal inflammation.In this article,we review the available data supporting the pathogenic role of IL-21 in IBD.

Interleukin-22 ameliorates acute severe pancreatitisassociated lung injury in mice

AIM: To investigate the potential protective effect of exogenous recombinant interleukin-22(r IL-22) on L-arginine-induced acute severe pancreatitis(SAP)-associated lung injury and the possible signaling pathway involved.METHODS: Balb/c mice were injected intraperitoneally with L-arginine to induce SAP. Recombinant mouse IL-22 was then administered subcutaneously to mice. Serum amylase levels and myeloperoxidase(MPO) activity in the lung tissue were measured after the L-arginine administration. Histopathology of the pancreas and lung was evaluated by hematoxylin and eosin(HE) staining. Expression of B cell lymphoma/leukemia-2(Bcl-2), Bcl-x L and IL-22RA1 m RNAs in the lung tissue was detected by real-time PCR. Expression and phosphorylation of STAT3 were analyzed by Western blot. RESULTS: Serum amylase levels and MPO activity in the lung tissue in the SAP group were significantly higher than those in the normal control group(P < 0.05). In addition, the animals in the SAP group showed significant pancreatic and lung injuries. The expression of Bcl-2 and Bcl-x L m RNAs in the SAP group was decreased markedly, while the IL-22RA1 m RNA expression was increased significantly relative to the normal control group(P < 0.05). Pretreatment with PBS did not significantly affect the serum amylase levels, MPO activity or expression of Bcl-2, Bcl-x L or IL-22RA1 m RNA(P > 0.05). Moreover, no significant differences in the degrees of pancreatic and lung injuries were observed between the PBS and SAP groups. However, the serum amylase levels and lung tissue MPO activity in the r IL-22 group were significantly lower than those in the SAP group(P < 0.05), and the injuries in the pancreas and lung were also improved. Compared with the PBS group, r IL-22 stimulated the expression of Bcl-2, Bcl-x L and IL-22RA1 m RNAs in the lung(P < 0.05). In addition, the ratio of p-STAT3 to STAT3 protein in the r IL-22 group was significantly higher than that in the PBS group(P < 0.05).CONCLUSION: Exogenous recombinant IL-22 protects mice against L-arginine-induced SAP-associated lung injury by enhancing the expression of anti-apoptosis genes through the STAT3 signaling pathway.