Performance of BALB/c and C57BL/6 mice under an incremental repeated acquisition of behavioral chains procedure

BALB/c (n = 8) and C57BL/6 (n = 11) male mice were trained under an incremental repeated acquisition (IRA) procedure using two distinct training procedures: forward and backward chaining. A new metric for assessing progress on the IRA procedure, progress quotient (PQ), quantified progress as the product of chain length and number of reinforcers earned during a session divided by the total number of reinforcers earned. BALB/c mice progressed further, had higher overall responding, earned more reinforcers, and acquired the response sequences faster than the C57BL/6 mice on both training procedures. There were only minimal effects of training procedure for either strain. The strain differences found between BALB/c and C57BL/6 mice confirm the importance of genetic background to behavior. C57BL/6 mice may be deficient in learning as compared with BALB/c mice but other contributing factors probably include overall responding, motivation, and more rapid satiation or habituation to sucrose reinforcement by the C57BL/6 mice. PQ is a sensitive and valid measure of progress for use in studies of mastery-based incremental repeated acquisition and BALB/c mice perform this challenging learning task better than do C57BL/6 mice.     

Intermedin ameliorates atherosclerosis in apoE null mice by modifying lipid profiles

Intermedin (IMD) is a recently discovered vasodilator peptide. We studied the role of IMD in the pathogenesis of atherosclerosis by investigating the ability of exogenous IMD to alter lipid profiles and ameliorate the development of atherogenic-diet induced atherosclerosis in ApoE−/− mice. Ten of eight-week-old male C57BL/6J mice were as control. Thirty of eight-week-old male ApoE−/− mice were fed with an atherogenic diet for 18 weeks. After feeding atherogenic diet for 12 weeks, the mice were equally and randomly divided into three groups. Normal saline was given in group A and C57BL/6J mice. Intermedin was given by mini osmotic pumps at the dosage of 100 ng/kg/h and 500 ng/kg/h in group B and group C respectively. After the treatment of IMD for 6 weeks, aortic ultrasonography of group C showed that IMD prevented the progression of atherosclerotic lesions and the increase of wall thickness in the aorta. Oil-red-O staining of the entire aorta and the atherosclerotic aortic root section showed 2 folds decrease atherogenic plaque (p < 0.05). Serum lipid profiles were measured, compared with the group A, in group C TC and LDL-C levels were decreased by 86.32% and 89.68%, respectively (both p < 0.05), meanwhile, HDL-C level was significantly increased by 74.82% (p < 0.05). These data indicate that exogenous administration of IMD could prevent the progression of atherosclerotic plaque. The possible underlying mechanisms may relate to the improvement of lipid profiles.     

Inactivation of Nxf2 causes defects in male meiosis and age-dependent depletion of spermatogonia

In eukaryotes, mRNA is actively transported from nucleus to cytoplasm by a family of nuclear RNA export factors (NXF). While yeast harbors only one such factor (Mex67p), higher eukaryotes encode multiple NXFs. In mouse, four Nxf genes have been identified: Nxf1, Nxf2, Nxf3, and Nxf7. To date, the function of mouse Nxf genes has not been studied by targeted gene deletion in vivo. Here we report the generation of Nxf2 null mutant mice by homologous recombination in embryonic stem cells. Nxf2-deficient male mice exhibit fertility defects that differ between mouse strains. One third of Nxf2-deficient males on a mixed (C57BL/6 × 129) genetic background exhibit meiotic arrest and thus are sterile, whereas the remaining males are fertile. Disruption of Nxf2 in inbred (C57BL/6J) males impairs spermatogenesis, resulting in male subfertility, but causes no meiotic arrest. Testis weight and sperm output in C57BL/6J Nxf2^−/Y mice are sharply reduced. Mutant epididymal sperm exhibit diminished motility. Importantly, proliferation of spermatogonia in Nxf2^−/Y mice is significantly decreased. As a result, inactivation of Nxf2 causes depletion of germ cells in a substantial fraction of seminiferous tubules in aged mice. These studies demonstrate that Nxf2 plays a dual function in spermatogenesis: regulation of meiosis and maintenance of spermatogonial stem cells.     

Macrophage ABCA5 deficiency influences cellular cholesterol efflux and increases susceptibility to atherosclerosis in female LDLr knockout mice

Objectives

To determine the role of macrophage ATP-binding cassette transporter A5 (ABCA5) in cellular cholesterol homeostasis and atherosclerotic lesion development.

Methods and results

Chimeras with dysfunctional macrophage ABCA5 (ABCA5^−M/−M) were generated by transplantation of bone marrow from ABCA5 knockout (ABCA5^−/−) mice into irradiated LDLr^−/− mice. In vitro, bone marrow-derived macrophages from ABCA5^−M/−M chimeras exhibited a 29% (P < 0.001) decrease in cholesterol efflux to HDL, whereas a 21% (P = 0.07) increase in cholesterol efflux to apoA-I was observed. Interestingly, expression of ABCA1, but not ABCG1, was up-regulated in absence of functional ABCA5 in macrophages. To induce atherosclerosis, the transplanted LDLr^−/− mice were fed a high-cholesterol Western-type diet (WTD) for 6, 10, or 18 weeks, allowing analysis of effects on initial as well as advanced lesion development. Atherosclerosis development was not affected in male ABCA5^−M/−M chimeras after 6, 10, and 18 weeks WTD feeding. However, female ABCA5^−M/−M chimeras did develop significantly (P < 0.05) larger aortic root lesions as compared with female controls after 6 and 10 weeks WTD feeding.

Conclusions

ABCA5 influences macrophage cholesterol efflux, and selective disruption of ABCA5 in macrophages leads to increased atherosclerotic lesion development in female LDLr^−/− mice.     

Macrophages from alpha 7 nicotinic acetylcholine receptor knockout mice demonstrate increased cholesterol accumulation and decreased cellular paraoxonase expression: A possible link between the nervous system and atherosclerosis development

Objective

The parasympathetic nervous system regulates inflammation in peripheral tissues through a pathway termed the “cholinergic anti-inflammatory reflex” (CAIR). Mice deficient in the alpha 7 nicotinic acetylcholine receptor (α7^−/−) have an impaired CAIR due to decreased signaling through this pathway. The purpose of this study was to determine if the increased inflammation in α7^−/− mice is associated with enhanced serum and macrophage atherogenicity.

Methods

We measured serum markers of inflammation and oxidative stress, and macrophage atherogenicity in mouse peritoneal macrophages harvested from α7^−/− mice on the background of C57BL/6 mice, as well as on the background of the atherosclerotic Apolipoprotein E-deficient (ApoE^−/−) mice.

Results

α7-Deficiency had no significant effects on serum cholesterol, or on markers of serum oxidative stress (TBARS and paraoxonase1 activities). However, α7-deficiency significantly increased serum CRP and IL-6 (p < 0.05) levels in atherosclerotic mice, confirming an anti-inflammatory role for the α7 receptor. Macrophage cholesterol mass was increased by 25% in both normal and atherosclerotic mice in the absence of the α7 receptor (p < 0.05). This was accompanied by conditional increases in oxidized LDL uptake and in macrophage total peroxide levels. Furthermore, α7-deficiency reduced macrophage paraoxonase2 mRNA and activity by 50-100% in normal and atherosclerotic mice (p < 0.05 for each), indicating a reduction in macrophage anti-oxidant capacity in the α7^−/− mice.

Conclusion

The above results suggest an anti-atherogenic role for the macrophage α7nAchr, through a mechanism that involves attenuated macrophage oxidative stress and decreased uptake of oxidized LDL.     

Resistance to age-related, normal body weight gain in RGS2 deficient mice

RGS2 (regulator of G protein signaling 2) is known to limit signals mediated via Gq- and Gs-coupled GPCRs (G protein coupled receptors), and it has been implicated in the differentiation of several cells types. The physiology of RGS2 knockout mice (rgs2^−/−) has been studied in some detail, however, a metabolic phenotype has not previously been reported. We observed that old (21-24 month) rgs2^−/− mice weigh much less than wild-type C57BL/6 controls, and exhibit greatly reduced fat deposits, decreased serum lipids, and low leptin levels. Lower weight was evident as early as four weeks and continued throughout life. Younger adult male rgs2^−/− mice (4-8 months) were found to show similar strain-related differences as the aged animals, as well improved glucose clearance and insulin sensitivity, and enhanced beta-adrenergic and glucagon signaling in isolated hepatocytes. In addition, rgs2^−/− pre-adipocytes had reduced levels of differentiation markers (Peroxisome proliferator-activated receptor γ (PPARγ); lipoprotein lipase (Lpl); CCAAT/enhancer binding protein α (CEBPα)) and also rgs2^−/− white adipocytes were small relative to controls, suggesting altered adipogenesis. In wild-type animals, RGS2 mRNA was decreased in brown adipose tissue after cold exposure (7 h at 4 °C) but increased in white adipose tissue in response to a high fat diet, also suggesting a role in lipid storage. No differences between strains were detected with respect to food intake, energy expenditure, GPCR-stimulated lipolysis, or adaptive thermogenesis. In conclusion this study points to RGS2 as being an important regulatory factor in controlling body weight and adipose function.     

Morphology of hypoxia following cryoablation in a prostate cancer murine model: Its relationship to necrosis, apoptosis and, microvessel density

The aim of this study is to investigate the tumor tissue changes in terms of hypoxia and demonstrate its relationship to vascularity and apoptosis following therapeutic cryoablation in a prostate tumor murine model. Total 67 male C57BL/J6 mice were assigned into sham-operation group and cryoablation group. Murine prostate tumors (RM-9) were inoculated subcutaneously in a right hind leg and treated with cryotherapy. Of 30 mice, tumor volumes were measured for 12 days following operation. Of 37 mice, tumor tissues were harvested in 24 h following operation, and histological/molecular changes were analyzed. Hematoxylin and eosin or immunohistochemical staining were utilized to quantify tumor necrosis, hypoxia (pimonidazole), vascularization (CD31), and apoptosis (cleaved caspase-3). The results showed that cryoablated tumors demonstrated significant delayed growth following treatment compared to controls. Pathological analysis revealed that the severity of hypoxia increased in the cryoablation arm compared to controls. Necrotic and apoptotic populations were also found to be increased in the cryoablation arm (P = 0.028 and 0.021). Hypoxia demonstrated a positive correlation with necrosis (r = 0.520, P = 0.001) and apoptosis (r = 0.474, P = 0.003), while showing negative correlation with microvessel density (MVD) (r = −0.361, P = 0.021). We concluded that in the peripheral areas from the cryoneedle impact site, strong hypoxic responses were found, which may play important role in tumor freezing injury. To our knowledge, this is the first report describing cryoablation-mediated changes of hypoxia at a molecular level in the prostate cancer murine model.     

Tumor necrosis factor alpha gene variants do not display allelic imbalance in circulating myeloid cells

Carriage of the TNF −308 A allele (rs1800629 A) has been associated with increased serum TNF-α levels, the development of sepsis syndrome, and fatal outcome, in severely traumatized patients (Menges et al., 2008 [1]). Herein, we analysed the putative allelic imbalance of TNF-α release from myeloid cells. Circulating peripheral blood cells from healthy human blood donors (n = 104) and monocyte-derived macrophages (n = 158) were analysed for their ex vivo capacity of TNF-α expression. Our findings indicate that carriage of the TNF −308 A allele is not associated with high TNF-α expression in circulating human leucocytes and monocyte-derived macrophages. Other cellular sources, e.g. tissue-resident cells like mast cells and/or tissue specific macrophages might be the cellular source of high TNF-α serum levels shortly after trauma.     

Influence of inflammatory response,infection, and pulmonary function in cystic fibrosis

Aims

Recurrent infections and activation of the inflammatory response affect the prognosis of cystic fibrosis (CF). We investigated the relationship between inflammatory response, infection, and pulmonary function in CF.

Main methods

A clinical-cross-sectional study was conducted with 86 subjects: control group (CG, n = 31, the same age and sex of the CF group), and CF group (CFG, n = 55, age: 1–16 years), further distributed into CFG negative or positive bacteriology (CFGB⁻/CFGB⁺), and CFG negative or positive Pseudomonas aeruginosa (CFGPa⁻/CFGPa⁺). Using the Wald test, multiple linear regression (95% confidence interval) was performed between CG and CFG, and between CG and each of the CF subgroups (CFGB⁻/CFGB⁺ and CFGPa⁻/CFGPa⁺). The inflammatory markers evaluated were myeloperoxidase (MPO), adenosine deaminase (ADA) activities, interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α), C-reactive protein (CRP), nitric oxide metabolites (NOx) levels, and total and differential leukocyte counts.

Key findings

After adjusting for sex and age, CFG compared to CG revealed an increase of MPO, IL-1β (P < 0.001 in all subgroups), and CRP: CFG (P = 0.002), CFGB⁻ (P = 0.007), CFGB⁺ (P = 0.009), CFGPa⁻ (P = 0.004) and CFGPa⁺ (P = 0.020). NOx (P = 0.001, P < 0.001), leukocytes (P = 0.002, P = 0.001), and neutrophils (P = 0.003, P < 0.001) were increased in CFGB⁺ and CFGPa⁺, respectively. A negative correlation between FEV₁ and leukocytes (P = 0.008) and FEV₁ and neutrophils (P = 0.031) resulted in CFG.

Significance

The inflammatory response characterized by the increase of MPO, IL-1β, and CRP is determinant for CF. Also leukocytosis due to neutrophilia determines the pulmonary function deficiency in this disease.     

Glutathione deficient C57BL/6J mice are not sensitized to ozone-induced lung injury

In this study we examined the role of the antioxidant glutathione (GSH) in pulmonary susceptibility to ozone toxicity, utilizing GSH deficient C57BL/6J mice that lack the expression of glutamate-cysteine ligase modifier subunit (GCLM). Gclm(−/−) knockout mice had 70% GSH depletion in the lung. Gclm(+/+) wild-type and Gclm(−/−) mice were exposed to either 0.3 ppm ozone or filtered air for 48 h. Ozone-induced lung hyperpermeability, as measured by total protein concentration in bronchoalveolar lavage fluid, was surprisingly lower in Gclm(−/−) mice than in wild-type mice. Lung hyperpermeability did not correlate with the degree of neutrophilia or with inflammatory gene expression. Pulmonary antioxidant response to ozone, assessed by increased mRNA levels of metallothionein 1 and 2, α-tocopherol transporter protein, and solute carrier family 23 member 2 (sodium-dependent vitamin C transporter) was greater in Gclm(−/−) mice than in Gclm(+/+) mice. These results suggest that compensatory augmentation of antioxidant defenses in Gclm(−/−) mice may confer increased resistance to ozone-induced lung injury.     

Insight into hypoxic preconditioning and ischemic injury through determination of nPKCε-interacting proteins in mouse brain

Cerebral hypoxic preconditioning (HPC) provides neuroprotection by intracellular signaling pathways. We previously demonstrated that novel protein kinase Cε (nPKCε) activation participated in cerebral HPC development. In this study, we explore the role of nPKCε in HPC-induced neuroprotection against middle cerebral artery occlusion (MCAO)-induced ischemic injury and identify its possible signaling molecules. A total of 131 adult male BALB/c mice were divided into eight groups: normoxic control (n = 9), HPC (n = 9), HPC + εV1–2 (n = 13), Sham (n = 19), HPC + sham (n = 6), Ischemia (I, 6 h MCAO, n = 31), HPC + I (n = 25) and HPC + εV1–2 + I (n = 19). nPKCε specific inhibitor εV1–2 was administered via intracerebroventricular injection. Western blot, 2,3,5-triphenyltetrazolium chloride staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling were applied to determine nPKCε membrane translocation, infarction volume and programmed cell death (PCD), respectively. Two-dimensional gel electrophoresis (2-De) and matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) were used to identify nPKCε-interacting proteins, followed by bioinformatics analysis of genee ontology (GO) to predict nPKCε-specific signaling pathways. Our results showed that HPC attenuates MCAO-induced brain injuries and stabilized nPKCεmembrane translocation in peri-infarct region, which was abolished by nPKCε-speecific inhibitor εV1–2. Proteomics analysis revealed 8 up- and 3 down-regulated nPKCε-interacting proteins both in cytosolic and particulate fractions of HPC mouse brain. GO analysis predicted 25 significant nPKCε-specific signaling pathways among the 16 identified nPKCε-interacting proteins in brain of HPC mice. This study is the first to report multiple nPKCε-interacting proteins and their signaling pathways in HPC mouse brain, suggesting that nPKCε signaling molecules is responsible for HPC-induced neuroprotection against cerebral ischemic injuries of mice.     

Measuring the antioxidant capacity of blood plasma using potentiometry

The use of potentiometry to measure plasma antioxidant capacity to contribute to oxidative stress evaluation is presented. In this assay, plasma (n = 60) diluted (0.3 to 1 ml) in phosphate buffer, pH 7.4, NaCl 9%, was submitted to potentiometry. A platinum wire was the working electrode and saturated calomel the reference. The results are presented as the difference between sample and buffer potential (ΔE). ΔE presented a good inverse correlation with added increasing concentrations of ascorbate (2.5−75 μmol/L; R = −0.99), urate (9.0−150 μmol/L; R = −0.99), and bilirubin (0.78−13 μmol/L; R = −0.99). Increase in the antioxidant capacity decreased ΔE. Depletion of the antioxidant capacity by tert-butylhydroperoxide (6.5−50 μmol/L) presented a direct correlation (0.97) with ΔE. Furthermore, ΔE presented an inverse correlation (R = −0.99) with increased antioxidant capacity of plasma (FRAP) induced by the addition of ascorbate (2.5−75 μmol/L). The response of the potentiometric method proved be adequate for measuring the plasma antioxidant depletion induced by acute exhaustive exercise in rats (control, n = 15; exercised, n = 15). This exercise decreased the concentration of urate (p < 0.05), decreased FRAP (p < 0.5), increased TBARS (p < 0.5), and decreased the potentiometer sensor response (p = 6.5 × 10⁻³). These results demonstrate the adequacy of potentiometry for evaluating the antioxidant capacity of blood plasma samples.     

1-D coordination chains of Cu(hfac)2 and Mn(hfac)2 bridged by phenyl-nitronylnitroxide derivatives

Two alternating 1-D metal-radical linear [L:Cu(hfac)₂]_n and zig-zag [L:Mn(hfac)₂]_n chains (where L = 4-trimethylsilylethynyl-1-(4,4,5,5-tetramethyl-3-oxylimidazoline-1-oxide)benzene) and hfac = hexafluoroacetylacetonate) are described and characterized by X-ray diffraction of their crystals. Bulk magnetic measurements of L:Cu(hfac)₂ indicated a ferromagnetic interaction with J = 6 cm⁻¹ and L:Mn(hfac)₂ yielded ferrimagnetic interactions with J = −95 cm⁻¹. For the latter, a strong increase of their magnetic moment at lowest temperatures was observed only at very low static magnetic field, while for H_dc > 0.05 T saturation effect led to a downward slope after reaching a maximum.     

Structure and magnetic properties of a tetranuclear Cu4O4 open-cubane in [Cu(L)]4·4H2O with L = (E)-N′-(2-oxy-3-methoxybenzylidene)benzohydrazide

The in-situ formed hydrazone Schiff base ligand (E)-N′-(2-oxy-3-methoxybenzylidene)benzohydrazide (L²⁻) reacts with copper(II) acetate to a tetranuclear open cubane [Cu(L)]₄ complex which crystallizes as two symmetry-independent (Z′ = 2) S₄-symmetrical molecules in different twofold special positions with a homodromic water tetramer. The two independent (A and B) open- or pseudo-cubanes with Cu₄O₄ cores of 4 + 2 class (Ruiz classification) each have three different magnetic exchange pathways leading to an overall antiferromagnetic coupling with J_1B = J_2B = −17.2 cm⁻¹, J_1A = −36.7 cm⁻¹, J_2A = −159 cm⁻¹, J_3A = J_3B = 33.5 cm⁻¹, g = 2.40 and ρ = 0.0687. The magnetic properties have been analysed using the H = −Σ_i,jJ_ij(S_iS_j) spin Hamiltonian.     

Solvent exchange, solvent interchange, aquation and isomerisation reactions of cis- and trans-[Co(tmen)2(NCMe)2] in water, Me2SO and MeCN: kinetics and stereochemistry

The synthesis and characterisation of cis- and trans-[Co(tmen)₂(NCCH₃)₂](ClO₄)₃ are described. Solvolysis rates have been measured by both ¹H NMR spectroscopy and UV-Vis spectrophotometry in dimethyl sulfoxide at 298.2 K. The cis isomer undergoes solvolysis by consecutive first-order reactions, k₁=5.61 × 10⁻⁴ and k₂=5.35 × 10⁻⁴ s⁻¹, each with steric retention. The measured solvolysis rate (single step reaction) for the trans isomer is k=1.54 × 10⁻⁵ s⁻¹. The solvent exchange rates have been measured by ¹H NMR spectroscopy in CD₃CN at 298.2 K: k_ex(cis)=k_ct + k_cc=2.0 × 10⁻⁵ and k_ex(trans)=k_tc + k_tt=4.56 × 10⁻⁶ s⁻¹. From these data, the measured cis-trans isomerisation rate (1.71 × 10⁻⁶ s⁻¹) and equilibrium position in CH₃CN (17% trans), the steric course for substitution in the exchange processes has been determined: trans reactant - 69% trans product; cis reactant - 99% cis product. Aquation rates for cis- and trans-[Co(tmen)₂(NCCH₃)₂](ClO₄)₃ have also been determined spectrophotometrically and by NMR; k_cis=1.3 × 10⁻⁴ and k_trans=2.7 × 10⁻⁵ s⁻¹. In both cases the steric course for the primary aquation step is indeterminate because the subsequent steps are faster. Where data are available, the [Co(tmen)₂X₂]ⁿ⁺ complexes are found to be consistently much more reactive than their [Co(en)₂X₂]ⁿ⁺ analogues.     

Temporary upregulation of anti-inflammatory cytokine IL-13 expression in the brains of CD14 deficient mice in the early stage of prion infection

CD14 deficient (CD14^−/−) mice survived longer than wild-type (WT) C57BL/6J mice when inoculated with prions intracerebrally, accompanied by increased expression of anti-inflammatory cytokine IL-10 by microglia in the early stage of infection. To assess the immune regulatory effects of CD14 in detail, we compared the gene expression of pro- and anti-inflammatory cytokines in the brains of WT and CD14^−/− mice infected with the Chandler strain. Gene expression of the anti-inflammatory cytokine IL-13 in prion-infected CD14^−/− mice was temporarily upregulated at 75 dpi, whereas IL-13 gene expression was not upregulated in prion-infected WT mice. Immunofluorescence staining showed that IL-13 was mainly expressed in neurons of the thalamus at 75 dpi. These results suggest that CD14 can suppress IL-13 expression in neurons during the early stage of prion infection.     

Plasma lecithin:cholesterol acyltransferase activity modifies the inverse relationship of C-reactive protein with HDL cholesterol in nondiabetic men

Lecithin:cholesterol acyltransferase (LCAT) is instrumental in high-density lipoprotein (HDL) maturation, but high LCAT levels do not predict low cardiovascular risk. LCAT may affect antioxidative or anti-inflammatory properties of HDL. We determined the relationship of plasma high-sensitivity C-reactive protein (CRP) with LCAT activity and evaluated whether LCAT activity modifies the decreasing effect of HDL cholesterol (HDL-C) on CRP, as an estimate of its anti-inflammatory properties. Plasma HDL-C, apolipoprotein (apo) A-I and LCAT activity (exogenous substrate method) were measured in 260 nondiabetic men without cardiovascular disease. CRP was correlated inversely with HDL-C and apo A-I, and positively with LCAT activity (P < 0.01 to 0.001). Multivariate regression analysis demonstrated that age- and smoking-adjusted plasma CRP levels were associated negatively with HDL-C (β = − 0.224, P < 0.001) and positively with LCAT activity (β = 0.119, P = 0.034), as well as with the interaction between HDL-C and LCAT activity (β = 0.123, P = 0.026). There was also an interaction between apo A-I and LCAT activity on CRP (β = 0.159, P = 0.005). These relationships remained similar after adjustment for apo B-containing lipoproteins. In conclusion, the inverse relationship of HDL-C with CRP is attenuated by LCAT activity at higher HDL-C levels. It is hypothesized that LCAT could mitigate HDL's anti-inflammatory or antioxidative properties at higher HDL-C concentrations.     

Association of the interleukin-10 − 592A/C, − 1082G/A and − 819T/C gene polymorphisms with type 2 diabetes: A meta-analysis

There is more evidence that interleukin-10 (IL-10), as a multifunctional regulatory cytokine of inflammatory responses, may have an important role in type 2 diabetes (T2D). However, genetic association studies that evaluated the relationship between IL-10 gene variants and T2D have produced conflicting results. The aim of this study was to determine whether the IL-10 gene polymorphisms (− 592A/C, − 1082G/A, − 819T/C) conferred susceptibility to T2D through a meta-analysis. A comprehensive search was conducted to examine all the eligible studies. A total of 9 studies involving 2838 T2D patients and 2773 controls were considered in the meta-analysis. Overall, there was no significant association between IL-10 − 592A/C and T2D (A vs C: OR = 0.93, P = 0.625; AA + AC vs CC: OR = 0.89, P = 0.511; AA vs AC + CC: OR = 0.93, P = 0.821). We failed to find the association between the IL-10 − 1082G allele and T2D (OR = 1.04, P = 0.430), but the genotypes of the IL-10 − 1082G/A polymorphism conferred a risk for the development of T2D (GA vs AA: OR = 1.21, P = 0.027; GG + GA vs AA: OR = 1.17, P = 0.048). Analysis of the − 819T/C polymorphism revealed no significant association with T2D (T vs C: OR = 1.04, P = 0.853; TT + TC vs CC: OR = 1.07, P = 0.834; TT vs TC + CC: OR = 1.08, P = 0.824). In conclusion, the present meta-analysis suggests association between the IL-10 − 1082G/A polymorphism and T2D. However, additional well-designed and larger scale primary studies are required to further evaluate the IL-10 gene polymorphisms and T2D.