Involvement of intrathecal activation of MrgC receptor in pathological pain and morphine tolerance / 生理学报

Rodent MrgC receptor (Mas-related G-protein-coupled receptor subtype C) shares 65% sequence homology and similarities in terms of expression pattern and binding profile with human Mas-related gene X receptor 1 (hMrgX1). Therefore, researchers generally explore the role of hMrgX1 by studying the function of MrgC receptor. Murine MrgC receptor is uniquely expressed in small-diameter neurons of dorsal root ganglia (DRG) and trigeminal ganglia (TG), which is closely related to the transmission process of pain. This review summarizes the analgesic effects of intrathecal activation of MrgC receptors in pathological pain and morphine tolerance.

Effects of pure total flavonoids from Citrus changshan-huyou on blood lipid metabolism in hyperlipidemic rats / 中国中药杂志

To observe and investigate the effects and mechanisms of the pure total flavonoids from Citrus changshan-huyou(PTFC) on blood lipid metabolism in hyperlipidemic rats. SD rats were fed with high fat diet for 4 weeks to induce hyperlipidemic rats model, meanwhile three dosages (50, 100, 200 mg•kg ⁻¹•d ⁻¹) of PTFC were administrated intragastrically for 4 weeks respectively.After 2 weeks of modeling, their tail blood was taken and serum TC, TG, and HDL-C levels were detected by biochemical method and their body weight was measured. After 4 weeks of modeling, their body weight was measured and liver weight was measured, then the levels of TC, TG, HDL-C, LDL-C, ALT, AST, MDA and SOD in serum were detected to calculate lipid comprehensive index(LDL-C/HDL-C and LDL-C/TC ratios) and atherogenic index(AI); in addition, MDA and SOD levels were detected by biochemical method. The hitopathological changes of the liver tissues were observed by HE staining; the protein expression levels of PPAR-α, Lpl, and Lipc were detected by ELISA; and the mRNA expression levels of PPAR-α in the liver tissue were detected by Real-time PCR. The results showed that gavage administration of the PTFC significantly decreased the body weight, liver weight, liver index, serum ALT and AST activities, the levels of serum TC, TG, LDL-C, LDL-C/HDL-C, AI and increased serum HDL and LDL/TC level. Moreover, the PTFC significantly enhanced SOD activity and decreased the concentration of MDA in serum and liver tissue. Further mechanism investigation indicated that PTFC inhibited serum lipid accumulation by increasing the expressions PPAR-α, Lpl, Lipc protein and PPAR-α mRNA of the liver tissues. PTFC could actively regulate blood lipid metabolism by ameliorating hepatic function, improving the body's antioxidant capacity, lowering levels of oxidative stress, as well as positively regulating the expression levels of PPAR-α, Lpl, Lipc protein and PPAR-α mRNA of the liver tissues in rats.

Pure total flavonoids from Citrus paradisi Macfad induce leukemia cell apoptosis in vitro / 中国结合医学杂志

<p><b>OBJECTIVE</b>To investigate the potential effect of pure total flavonoids from Citrus paradisi Macfad peel (PTFC) on the proliferation of human myeloid leukemia cells Kasumi-1, HL-60 and K562, and the underlying mechanisms.</p><p><b>METHODS</b>PTFC was extracted from Citrus paradisi Macfad peel and was identified by high performance liquid chromatography. The effect of PTFC on the proliferation and apoptosis of leukemia cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, fluorescent microscopy and flow cytometry, respectively. The effect of PTFC on the expression levels of apoptosis-related regulators was determined by Western blot assay.</p><p><b>RESULTS</b>Treatment with PTFC inhibited leukemia cell proliferation in a dose- and time-dependent manner and triggered Kasumi-1 cell apoptosis. Treatment with PTFC significantly increased the levels of activated poly adenosine diphosphate-ribosepolymerase and caspase-3/-9, but reduced the levels of Mcl-1 expression in Kasumi-1 cells. However, PTFC did not obviously induce HL-60 cell apoptosis.</p><p><b>CONCLUSION</b>PTFC inhibited leukemia cell proliferation and induced their apoptosis by modulating apoptosisrelated regulator expression in leukemia cells in vitro.</p>

Activation of spinal MrgC receptors inhibits hyperalgesia in rats / 生理学报

This study was aimed to investigate the mechanisms of the modulation effect of activation of spinal Mas-related gene C (MrgC) receptors on hyperalgesia induced by intraplantar (i.pl.) injection of (Tyr6)-γ2-MSH-6-12 (MSH) or complete Freund's adjuvant (CFA). Paw withdrawal latency test and immunohistochemistry were used to observe the effect of intrathecal (i.t.) administration of MSH or BAM8-22, two selective agonists of MrgC receptor, in hyperalgesia in rats. The results showed that i.t. administration of MSH inhibited acute hyperalgesic response induced by i.pl. application of MSH, while did not change thermal nociceptive threshold in naïve rats. The i.t. administration of MSH also attenuated CFA-induced inflammatory hyperalgesia. However, i.t. administration of the μ-opioid receptor (MOR) antagonist CTAP blocked the induction of delayed anti-hyperalgesia by MSH. The i.t. injection of BAM8-22 at a dose of 30 nmol evidently reduced the number of CFA-evoked nitric oxide synthase (NOS)-positive neurons and the expression of calcitonin gene-related peptide (CGRP)-immunoreactivity positive nerve fibers at L3-L5 segments of the spinal cord. These results suggest that the activation of MrgC receptor in CFA-induced inflammation reduces inflammatory hyperalgesia through inactivation of NOS neurons and down-regulation of CGRP expressions, and generates delayed but long-lasting anti-nociception through the endogenous activation of MOR via indirect mechanisms. Agonists for MrgC receptors may, therefore, represent a new class of antihyperalgesics for treating inflammatory pain because of the highly specific expression of their targets.

Regulation of pure total flavonoids from Citrus on TH17/Treg balance in mice with NASH / 中国中药杂志

This study aimed to investigate the involved immunologic mechanism of pure total flavonoids from Citrus (PTFC) on the development of non-alcoholic steatohepatitis (NASH). C57BL/6 mice were fed with high .fat diet for 16 weeks to induce the NASH model, and from the 7th week three dosages (25, 50 and 100 mg x kg(-1) x d(-1)) of PTFC were administrated intragastric for 10 weeks respectively. Serum TG, CHOL, ALT, AST were determined by biochemical assay, histopathological changes of the liver tissue were observed by HE staining, expression of RORyt and Foxp3 mRNA of the liver tissue was detected by Real-time PCR, and serum IL-17, IL-6, IL-10 and IL-4 were determined by.Cytometric Beads Array. As a result, we find that after the administration of PTFC, the in- flammation of the liver tissue of NASH mice was attenuated, liver function was improved, and the expression of RORgammat mRNA was higher in the liver tissue while which was lower of Foxp3 mRNA, the level of proinflammatory cytokines IL-17 and IL-6 decreased and the level of suppressive cytokines IL-10 and IL-4 increased. These data show that PTFC protects the development of NASH through regulating the Th17/Treg balance and attenuating inflammation.

Effect of pure total flavonoids from citrus on hepatic SIRT1/PGC-1alpha pathway in mice with NASH / 中国中药杂志

<p><b>OBJECTIVE</b>To observe the effect of pure total flavonoids from Citrus (PTFC) on the hepatic fatty degeneration, inflammation, oxidative stress and SIRT1/PGC-1alpha expressions in mice with non-alcohol steatohepatitis (NASH), and discuss the action mechanism of PTFC on NASH.</p><p><b>METHOD</b>Mice were given high-fat diet for 16 weeks to induce the NASH model. Since the seventh week after the model establishment, the mice were intervened with 100, 50 and 25 mg x kg(-1) x d(-1) PTFC for 10 weeks. The pathologic changes in hepatic tissues were observed with HE staining. The contents of TG, CHOL in hepatic tissue, as well as the levels of AST, ALT in serum were detected by using the biochemical process. The expression of SIRT1, PGC-1alpha and MnSOD mRNA in hepatic tissues were detected with Real-time PCR assay. SIRT1, PGC-1alpha protein and 8-OHdG expressions were determined with the immunohistochemical method. The SOD level in hepatic tissues was tested by the xanthine oxidase method. The MDA content in hepatic tissues was examined by the thiobarbituric acid method.</p><p><b>RESULT</b>The contents of TG, CHOL, NAFLD activity scores and ALT level in serum in hepatic tissues of mice in the model induced by fat-rich diet were obviously higher than that of the normal group (P < 0.010. The SIRT1, PGC-1alpha, MnSOD mRNA and protein expression in hepatic tissues were significantly lower than that of the normal group (P < 0.01). The expression of 8-OHdG and the content of MDA in hepatic tissues were obviously higher than that of the normal group (P < 0.01). After the intervention with different doses of PTFC, the NAFLD activity scores, the content of TG and the level of AST in serum were notably lower than that of the normal group (P < 0.01, P < 0.05); whereas the SIRT1, PGC-1alpha, MnSOD mRNA and protein expression were obviously higher than that of the normal group (P < 0.01, P < 0.05), with the significant decrease in the expression of 8-OHdG and the content of MDA (P < 0.01).</p><p><b>CONCLUSION</b>Oxidative stress/lipid peroxidation enhancement in in NASH mice induced by high-fat diet may be related to the changes in SIRT1/PGC-1alpha signal transduction pathway. PTFC could enhance the anti-oxidant capacity in liver, relieve the damage of reactive oxygen during the fatty acid metabolic process, and prevent NASH from the occurrence and development by regulating the SIRT1/PGC-1alpha signal pathway.</p>

Apoptosis of multiple myeloid cells induced by polysaccharides extracts from Hedyotis diffusa and its mechanism / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the proliferation inhibition and apoptosis effects of polysaccharides extracts from Hedyotis diffusa (PEHD) on multiple myeloma (MM) cell line RPMI 8226 cells in vitro, so as to provide experimental theory for the clinical application in the treatment of MM.</p><p><b>METHODS</b>MTT assay was used to examine the effects of PEHD on cell growth. The apoptotic cells were analyzed by flow cytometry with AnnexinⅤ/PI staining. Hoechst staining was used to observe the morphological changes of RPMI 8226 cell apoptosis. The expression levels of caspase-3,-8,-9, PARP, nucleoprotein NF-κB protein and other channel protein were assayed by Western blotting method.</p><p><b>RESULTS</b>The growth of RPMI 8226 cells were suppressed after treatment with PEHD, the highest inhibition rate reached to 92.3%, the results in the doses from 1 to 4 mg/ml showed a dose-and-time-dependent manner. The proportion of apoptotic cells in 1, 2 and 3 mg/ml PEHD treatment groups for 24 h were 22.52%, 62.31% and 69.94%, respectively, and significantly higher than that of control 8.93%. After treated with PEHD, apoptotic body appeared in RPMI 8226 cells nucleus and the number of apoptotic body increased in a dose-dependent manner. With the increasing of PEHD concentration, the expression of caspase-8,-9,-3 and PARP protein increased. The expression of Mcl-1, Bcl-xl, Bid and Bim protein decreased gradually, but the expression of Bax, Bak and Bad protein increased, and the expression of p-AKT protein (60 kDa) and NF-κB obviously decreased.</p><p><b>CONCLUSION</b>PEHD could inhibited the growth of RPMI 8226 cells and displayed a dose-and-time-dependent manner, its mechanism may involve cell apoptosis induction, which was associated with the activation of caspase-8, caspase-9, and caspase-3 protein and the down-regulation of p-AKT and NF-κB protein expression.</p>

Inhibition of Jumi extraction on growth of human cervical cancer cell line HeLa / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To explore the inhibition of Jumi (traditional Chinese medicine) extraction on the growth of human cervical cancer cell line HeLa.</p><p><b>METHODS</b>Nude mouse model of human cervical cancer HeLa cell transplantation was established. The nude mice bearing cancer were randomly divided into control group and Jumi treated groups with different concentration (0.001, 0.002, 0.005, 0.01 mg/ml). The growth of cervical cancer cell in experimental mice were measured. Cultured HeLa cells were incubated in culture media with or without Jumi extract for 48 hours. Cell proliferation rate, cell apoptosis, caspase-3/7 and caspase-6 activity were determined by MTT colorimetric assay, flow cytometry analysis and spectrophotometric detection, respectively.</p><p><b>RESULTS</b>With the increase of the concentration of Jumi extract, tumor-bearing mice tumor inhibition rate gradually increased. The proliferation of cultured HeLa cells were significantly inhibited by Jumi extract in a dose-dependent manner. IC50 was 0.004 mg/ml. Apoptosis rates in the cells treated with Jumi extract were higher than those of the control group. Compared with the control group, except for lower Jumi treated group (0.001 mg/ml), caspase-3/7 and caspase-6 activity were significantly increased in the all Jumi treated groups.</p><p><b>CONCLUSION</b>Jumi extract can inhibit the proliferation of human cervical cancer cell line HeLa in vitro in a dose-dependent manner and promote cell apoptosis through caspase-3, caspase-7 and caspase-6 pathway.</p>

Current pattern of Chinese dialysis units: a cohort study in a representative sample of units / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Understanding the characteristics of Chinese dialysis patients and the current practice trends is the first step to evaluate the association between practice pattern and outcome in these populations. In the present study, we evaluated the status of medical treatment and characteristic features of chronic dialysis patients in China.</p><p><b>METHODS</b>Through a clustering sampling, we selected 9 centers from the largest dialysis facilities in 6 cities around China. All adult undergoing dialysis in the selected units were screened. A total of 2388 (1775 on hemodialysis (HD) and 613 on peritoneal dialysis (PD)) patients were finally enrolled. All data were collected at enrollment on the bases of review of medical records.</p><p><b>RESULTS</b>In this cohort, 1313 (55.0%) were male. The mean age was 54 years old. The median time for dialysis was 26 months (12 - 51 months). Seventy-five percent of patients were on HD and 25.0% on PD. Among PD patients, about 21% patients did not receive dialysis adequacy. For HD patients, about 14.0% of them did not achieve dialysis adequacy when the target of kt/V was set as 1.2. Only 44.7% of patients achieved blood pressure target of 140/90 mmHg. About 60% of patients did not reach the hemoglobin target of 110 g/L even though 85.0% of them were treated with erythropoietin. In addition, 48.5% of the patients had uncontrolled mineral metabolism revealed by the high calcium-phosphate product. Compared with HD patients, higher level of serum glucose, triglyceride, and total and low density lipoprotein cholesterol were more common in PD patients.</p><p><b>CONCLUSIONS</b>This observational study suggests that many Chinese dialysis patients did not achieve the therapeutic target, particularly in blood pressure control, anemia correction, and mineral balance. PD patients were more likely to suffer metabolic disturbance.</p>

Bovine adrenal medulla 22 attenuates hyperalgesia in the early phase of complete Freund's adjuvant-induced inflammation in rats / 生理学报

The present study investigated the effects of intrathecal (i.t.) application of bovine adrenal medulla 22 (BAM22), an endogenous opioid peptide potently activating opioid receptors and sensory neuron-specific receptor (SNSR), on a model of complete Freund's adjuvant (CFA)-induced inflammatory pain. Unilateral, but not bilateral, inflammatory pain was induced by intraplantar (i.pl.) injection of CFA in one side, as indicated by the shortened paw withdrawal latency and the increased edema of paw. Paw withdrawal latency test, paw edema determination and immunohistochemistry were used in CFA-induced inflammatory pain model after i.t. administration of BAM22 or saline. It was found that administration of BAM22 dose-dependently attenuated CFA-induced hyperalgesia and edema, and resumed antinociceptive effects against thermal stimulation in behavioral test. In 10 nmol BAM22 group, paw withdrawal latency was resumed to 83.2% of normal, and edema increased only by 60% of normal at 48 h. The potency of BAM22 was 33.5% of maximal possible effect (MPE) at 24 h, and the antinociception persisted for at least 1 h. Furthermore, i.t. treatment of 10 nmol BAM22 evidently decreased the expressions of CFA-evoked neuronal nitric oxide synthase (nNOS)-positive cells and calcitonin gene-related peptide (CGRP)-immunoreactivity positive nerve fibers by 25.6% (P<0.01) and 25.2% (P<0.001) compared with saline group, respectively, at L3-L5 segments of the spinal cord. Small and medium CGRP-positive cells were 57.4% and 35.2% in dorsal root ganglion (DRG) in 10 nmol BAM22 group, respectively, which were remarkably lower than those in saline group (P<0.001). The present study suggests that BAM22 relieves CFA-induced thermal hyperalgesia in the early phase and resumes antinociceptive effects through down-regulation of nNOS and CGRP expressions in DRG and spinal cord, which is possibly mediated via SNSR.

Effects of diazoxide on the mitochondrial ultrastructure and permeability in donor rat myocardium / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the effect of diazoxide (DE) on the myocardial ultrastructure and opening of maitochondrial permeability transition pore (MPTP) in donor rat heart suffered from long-term hypothermic preservation.</p><p><b>METHODS</b>The Langendorff model of isolated rat heart was used. The hearts were stored in 4 degrees C Celsior solution containing different concentration of DE (15, 30, or 45 micromol/L) for 9 h followed by 60 min of reperfusion. The recovery of rate-pressure product (RPP) was observed. The opening of MPTP and myocardial mitochondria ultrastructure were also evaluated.</p><p><b>RESULTS</b>(1) As compared with the celsior solution preserved group, DE (30 micromol/L) increased recovery of RPP during reperfusion and inhibited the opening of MPTP. DE also alleviated the myocardial mitochondrial ultrastucture damage induced by long-term hypothermic preservation. (2) The above effects of DE were attenuated by a mitoK(ATP) channel inhibitor 5-hydroxydecanoate and a MPTP opener atractyloside.</p><p><b>CONCLUSION</b>In the donor rat heart, DE protects myocardial mitochondria ultrastructure against long-term hypothermic preservation injury via inhibiting the opening of MPIP.</p>

Dynamic changes of Smac/DIABLO protein expression in rat donor myocardium suffered from hypothermic preservation / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effect of different duration of hypothermic preservation on the expression of Smac/DIABLO protein in rat hearts.</p><p><b>METHODS</b>The Langendorff model of isolated rat heart was used. After stored in 4 degrees C Celsior solution for different time (0, 3, 6, 9 or 12 h), the activity of SOD and the content of MDA in heart mitochondria were measured. Cell apoptosis was detected by TUNEL technique. The expression of Smac/DIABLO protein was also analyzed by Western blotting.</p><p><b>RESULTS</b>(1) After hypothermic preservation, the activity of SOD was decreased and the content of MDA was increased in rat hearts in a time-dependent manner. (2) Prolonged the hypothermic preservation, the percentage of apoptotic cell also enhanced. (3) After long-term of cold preservation, the expression of Smac/DIABLO protein increased at 3-6 h of preservation but decreased after 9 h.</p><p><b>CONCLUSION</b>Prolonged the hypothermic preservation might lead to the expression of Smac/DIABLO protein and induce cardiomyocytes apoptosis, which may in turn result in malfunction of cardiomyocytes.</p>

Effects of diazoxide on Fas/FasL protein expressions in rat myocardium suffered from long-term hypothermic preservation / 生理学报

The purpose of this study was to investigate the effect of a mitochondrial ATP-sensitive potassium channel (mitoK(ATP)) opener, diazoxide (DE), on Fas/FasL protein expressions in rat heart suffered from long-term hypothermic preservation. The Langendorff isolated rat heart model was used. The hearts were stored in 4 °C Celsior solution with or without (control) DE for 8 h followed by 60 min of reperfusion. The recovery of rate-pressure product (RPP) was observed. Apoptotic cardiomyocytes were detected by TdT-mediated dUTP nick end labeling (TUNEL) technique. The expressions of Fas/FasL proteins were also analyzed by immunohistochemical method. The results showed that compared with the control group, DE (30 mmol/L) increased the recovery of RPP during reperfusion, reduced the percentage of apoptotic cells and the expressions of Fas and FasL proteins in rat hearts suffered from 8 h of hypothermic preservation. The above effects of DE were attenuated by a mitoK(ATP) channel inhibitor 5-hydroxydecanoate (5-HD). These results indicate that DE could alleviate rat myocardial injury induced by ischemia-reperfusion through reducing the expressions of Fas and FasL proteins via opening of mitoK(ATP)channel.

Effect of postconditioning on rat hearts suffered from long-term hypothermic preservation / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To assess the effect of postconditioning on cardiac protection of rat hearts suffered from long-term hypothermic preservation.</p><p><b>METHODS</b>The Langendorff model of isolated rat heart was used. After 30 min of stabilization, the hearts were stored in 4 degrees C Celsior solution for 3 or 5 h followed by 60 min of reperfusion. Postconditioning was initiated by 3 cycles of 30 s ischemia followed by 30 s reperfusion at the beginning of subsequent persistent reperfusion. The recovery of cardiac contractile function and arrhythmia score were observed.</p><p><b>RESULTS</b>(1) Compared with control group, postconditioning increased the recovery of heart rate (HR), left ventricular systolic pressure (LVDP), maximal rise/fall rate of ventricular pressure (dP/dt(max)) and coronary flow (CF) and rate-pressure product (RPP) during reperfusion after 3 h of hypothermic preservation. However, left ventricular end-diastolic pressure (LVEDP) and the cardiac arrhythmia score during the first 10 min of reperfusion was significantly lower in 3 h postconditioning group than that in 3 h control group. (2) The rat hearts treated by postconditioning with 5-HD(100 micromol/L) abolished the amelioration of contract function induced by postconditioning. And it could also increase the cardiac arrhythmia score. (3) Compared with 5 h control group, the HR, LVDP,dP/dt(max), CF, LVEDP, RPP and the cardiac arrhythmia score were not significantly different in postconditioning treated hearts during reperfusion after 5 h of hypothermic preservation.</p><p><b>CONCLUSION</b>Postconditioning could provide the cardiac protection on 3 h hypothermic preserved rat hearts,but not on 5 h hypothermic preserved rat hearts. The cardiac protection effect might be partly associated with activation of selective mitochondrial ATP-sensitive potassium channel.</p>

Differential reversal effect of intrathecal bovine adrenal medulla peptide 22 on morphine tolerance in rats / 生理学报

Bovine adrenal medulla 22 (BAM22), an endogenous opioid peptide, is one of the cleavage products of proenkephalin A. It potently activates opioid receptors and sensory neuron-specific receptor (SNSR). The present study was aimed at investigating the effect of BAM22 on morphine tolerance. Intrathecal (i.t.) administration of morphine for 7 d produced morphine tolerance in rats. Then the rats were divided into three groups in which morphine, saline or BAM22 were administered i.t., respectively, on day 8, and morphine was given to all of the animals on day 9. It was found that morphine administered on day 9 resumed antinociceptive effects in BAM22 group, but not in saline or morphine group. The potency of morphine in BAM22 group was 48.5% of the maximal possible effect (MPE) detected by paw withdrawal test and the antinociception persisted for approximately 1 h. Following the similar treatment, morphine administered on day 9 reduced nocifensive behaviors by 3.2 min and 24 min in BAM22 group in the first and second phases, in the formalin test, respectively. The decreases were 45% and 82% of the corresponding values observed in saline group. Furthermore, following the treatment with BAM22 (10 nmol) on day 8 in morphine-tolerance rats, morphine administered on day 9 decreased the expressions of the heat-evoked c-Fos-like immunoreactivity (FLI) protein by approximately 80% in laminae I-II, III-IV and V-VI in the spinal cord at L4-L5 compared with that in saline or morphine group. The present study provided evidence at behavioral and cellular levels showing that BAM22 resumed antinociception of morphine. The results that the reversal effect of BAM22 on morphine tolerance was more efficient in persistent pain model than in acute pain may indicate that BAM22 differentially modulates morphine tolerance. The present study suggests that SNSR is involved in the modulation of morphine tolerance.

Relationship between antimicrobial resistance and aminoglycoside-modifying enzyme gene expressions in Acinetobacter baumannii / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Acinetobacter baumannii is one of the main gram-negative bacilli in clinical practice. Nosocomial infections caused by multi-drug resistance Acinetobacter baumannii is very difficult to treat. This study was designed to investigate the antimicrobial resistance characteristics and four resistant gene expressions of aminoglycoside-modifying enzymes including N-acetyltransferases and O-phosphotransferases in Acinetobacter baumannii.</p><p><b>METHODS</b>Bacterial identification and antimicrobial susceptibility test were performed by Phoenix system in 247 strains of Acinetobacter baumannii. Minimal inhibitory concentrations (MICs) of seven aminoglycosides including gentamicin, amikacin, kanamycin, tobramycin, netilmicin, neomycin and streptomycin in 15 strains of multi-drug resistant Acinetobacter baumannii were detected by agar dilution. Four aminoglycoside-modifying enzyme genes were amplified by polymerase chain reaction (PCR) and verified by DNA sequencer.</p><p><b>RESULTS</b>The resistance rates of 247 strains of Acinetobacter baumannii against cefotaxime, levofloxacin, piperacillin, aztreonam, tetracycline, ciprofloxacin and chloramphenicol were more than 50%. Imipenem and meropenem showed high antibacterial activities with resistance rates of 3.2% and 4.1%. MIC50 and MIC90 of gentamicin, amikacin, streptomycin and kanamycin in 15 strains of multi-drug resistant Acinetobacter baumanii were all more than 1024 mg/L, and the resistance rates were 100%, 100%, 100% and 93.3%, respectively. But their resistance rates to tobramycin, netilmicin and neomycin were 86.7%, 93.3% and 46.7%, respectively. Three modifying enzyme genes, including aacC1, aacC2 and aacA4 genes, were found in 15 strains, but aphA6 had not been detected. Their positive rates were 93.3%, 20.0% and 20.0%, respectively. These three genes existed simultaneously in No.19 strain. Nucleotide sequences of aacC1, aacC2 and aacA4 genes shared 100%, 97.9% and 99.7% identities with GenBank genes (AY307113, S68058 and AY307114).</p><p><b>CONCLUSION</b>Multi-drug resistant Acinetobacter baumannii strains are rapidly spreading in our hospital, and their resistance to aminoglycosides may be associated with aminoglycoside-modifying enzyme gene expressions.</p>