Safety and efficacy of waterjet debridement vs. conventional debridement in the treatment of extremely severe burns: A retrospective analysis.

INTRODUCTION: Patients with extremely severe burns often require rapid wound closure with a tangential excision or escharectomy combined with a skin graft to reduce life-threatening complications such as infection. Traditional tangential excision surgery using the Watson or Humby knife does not allow accurate excision of necrotic tissue and often removes too much active tissue, which is detrimental to the rapid healing of the wound. Importantly, the Versajet hydrosurgical system, with its smaller handle, allows for more precise excision of necrotic burn tissue and preserves more active dermal tissue, positively affecting wound healing and scarring. This study compared the safety and efficacy of hydrosurgical combined with autologous skin grafting to conventional excision combined with autologous skin grafting in patients with extremely severe burn. METHODS: Information of sixty burn patients with total body surface area (TBSA) > 50 % treated at the first affiliated hospital of Anhui Medical University from January 2019 to August 2022 were analyzed. The patients were divided into a conventional debridement group (n = 37) and a hydrosurgical debridement group (n = 23) according to the approach used. The hydrosurgical debridement group and the conventional debridement group were compared from the difference between the duration of the first debridement surgery, wound healing time, the changes of red blood cells and hemoglobin concentration postoperative, total blood transfusion, hospitalization cost, skin grafting frequency, procalcitonin, wound bacterial culture, albumin and prealbumin. RESULTS: Information on age, gender, weight, inhalation injury, hypovolemic shock, preoperative procalcitonin, preoperative albumin, preoperative prealbumin, the operation frequency (n ≥ 3), preoperative trauma culture and postoperative trauma culture were compared between both groups (P > 0.05). Operative time and wound healing time were significantly shorter in patients with hydrosurgical debridement combined with autologous skin grafting than those in the control group (P < 0.05), while hospitalization costs were not significantly different between the two groups (P > 0.05). The changes of red blood cells and hemoglobin concentration during the postoperative period in the hydrosurgical debridement group were less significantly than those in the conventional debridement group (P < 0.05). The total amount of red blood cells transfused during hospitalization was significantly lower in the hydrosurgical debridement group than that in the conventional debridement group (P < 0.05), but the total amount of fresh frozen plasma transfused during hospitalization was not statistically significant between the two groups (P > 0.05). Albumin on the third day after surgery and prealbumin on the first, third and fifth day after surgery improved more significantly than those in the control group(P < 0.05), however, there were no significant differences between the two groups in albumin on the first and fifth postoperative days (P > 0.05). The PCT level in the conventional debridement group was significantly higher than that in the hydrosurgical debridement group on the first, third and fifth days after surgery(P < 0.05). CONCLUSION: The hydrosurgical debridement group presented with shorter operative time, less blood loss during surgery, faster postoperative nutritional recovery, less postoperative inflammatory response and faster wounds healing, and did not increase the hospitalization cost, postoperative bacterial culture of the wounds and the number of skin grafting surgeries. In patients with extremely severe burn, hydrosurgical debridement combined with autologous skin grafting group is safer and more effective than those in the conventional debridement combined with autologous skin grafting group.

Diagnostic value of procalcitonin and red blood cell distribution width at admission on the prognosis of patients with severe burns: A retrospective analysis.

The plasma procalcitonin (PCT) concentration and red blood cell distribution (RDW) value after severe burns can be used as prognostic indicators, but at present, it is difficult to give consideration to sensitivity and specificity in diagnosing the prognosis of severe burns with a single indicator. This study analysed the diagnostic value of plasma PCT concentration and RDW value at admission on the prognosis of severe burn patients to improve its sensitivity and specificity. A total of 205 patients with severe burns who were treated in the First Affiliated Hospital of Anhui Medical University from November 2017 to November 2022 were retrospectively analysed. The optimal cut-off values of plasma PCT concentration and RDW were analysed and counted through the subject curve (ROC curve). According to the cut-off value, patients were divided into high PCT group and low PCT group, high RDW group and low RDW group. The independent risk factors of severe burns were analysed by single-factor and multiple-factor COX regression. Kaplan-Meier survival was used to analyse the mortality of high PCT group and low PCT group, high RDW group and low RDW group. The area under the curve of plasma PCT concentration and RDW value at admission was 0.761 (95% CI, 0.662-0.860, P < .001), 0.687 (95% CI, 0.554-0.820, P = .003) respectively, and the optimal cut-off values of serum PCT concentration and RDW were 2.775 ng/mL and 14.55% respectively. Cox regression analysis found that age, TBSA, and RDW were independent risk factors for mortality within 90 days after severe burns. Kaplan-Meier survival analysis showed that there was a significant difference in the 90-day mortality rate of severe burns between the PCT ≥ 2.775 ng/mL group and the PCT < 2.775 ng/mL group (log-rank: 24.162; P < .001), with the mortality rate of 36.84% versus 5.49%, respectively. The 90-day mortality rate of severe burns was significantly different between the RDW ≥ 14.55% group and the RDW < 14.55% group (log-rank: 14.404; P < .001), with the mortality rate of 44% versus 12.2% respectively. The plasma PCT concentration and RDW value at admission are both of diagnostic value for the 90-day mortality of severe burns, but the plasma PCT concentration has higher sensitivity and the RDW value has higher specificity. Age, TBSA, and RDW were independent risk factors for severe burns, and then plasma PCT concentration was not independent risk factors.

Red blood cell distribution width is an independent risk factor in the prediction of acute respiratory distress syndrome after severe burns.

BACKGROUND: The occurrence of acute respiratory distress syndrome (ARDS) significantly increases the mortality and morbidity of major burns; there are few laboratory markers that predict the development of ARDS in severe burns. This study was to investigate the relationship between complete blood count (CBC) parameters and the incidence of ARDS in severe burn patients. METHODS: An eight-year retrospective study was performed on 610 severe burn patients who were admitted to the First Affiliated Hospital of Anhui Medical University and Rui Jin Hospital of Shanghai Jiao Tong University from January 2008 to December 2015. The patients were divided into two groups based on the development of ARDS. A blood sample was taken at admission and CBC parameters were examined. Univariate logistic regression analysis was used to evaluate the risk factors for the development of ARDS. RESULTS: Of these 610 patients, 143 developed ARDS giving a rate of 23.44%. The percentage of deep second degree and full thickness burn, inhalation injury and red blood cell distribution width (RDW) were independently associated with the development of ARDS in severe burn patients. Every 1% increase in RDW was associated with a 29% increase in the risk to develop ARDS. CONCLUSIONS: The findings of this study suggest that an elevated RDW is associated with an increased risk of ARDS and RDW is an independent risk factor in the prediction of ARDS after severe burns.

Nocardia rubra cell wall skeleton accelerates cutaneous wound healing by enhancing macrophage activation and angiogenesis.

Objective This study was performed to investigate the effect of Nocardia rubra cell wall skeleton (N-CWS) on wound healing of full-thickness skin defects. Methods Two 2- × 2-cm full-thickness wounds, one on each side of the midline, were made on the back of 12 rats. One wound was covered with Vaseline gauze soaked in normal saline, whereas the other was covered with Vaseline gauze and N-CWS. Wound dressings were changed every other day from day 0 (wound creation) to day 11. Four of the 12 rats were killed on day 7, and biopsy samples were obtained for biochemical and histopathological analyses. The expression levels of CD31, CD68, and F4/80 in the tissues were examined immunohistologically. The expression of transforming growth factor (TGF)-ß1 in the wound was determined by western blot. Results N-CWS increased the wound healing rate, reduced the complete wound healing time, and increased the expression levels of CD31, CD68, and F4/80 on day 7. The TGF-ß1 expression level in the wound was significantly higher in the N-CWS group than in the control group on day 7. Conclusions N-CWS can activate macrophages, increase TGF-ß1 expression, and enhance angiogenesis and thus accelerate cutaneous wound healing.

Protective effects of tiopronin against high fat diet-induced non-alcoholic steatohepatitis in rats.

AIM: To study the protective effects of tiopronin against high fat diet-induced non-alcoholic steatohepatitis in rats. METHODS: Male Sprague-Dawley rats were given a high-fat diet for 10 weeks. The rats were administered tiopronin (20 mg/kg) or a positive control drug ursodeoxycholic acid (UDCA, 15 mg/kg) via gavage daily from week 5 to week 10. After the rats were sacrificed, serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), triglyceride (TG), free fatty acids (FFA), high-density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C), and liver homogenate FFA, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) were measured using commercial analysis kits. The expression levels of CYP2E1 mRNA and protein were determined using RT-PCR and immunoblot assays, respectively. RESULTS: Tiopronin significantly lowered both the serum ALT and AST levels, while only the serum ALT level was lowered by UDCA. Tiopronin significantly decreased the serum and liver levels of TG, TC and FFA as well as the serum LDL-C level, and increased the serum HDL-C level, while UDCA decreased the serum and liver TC levels as well as the serum LDL-C level, but did not change the serum levels of TG, FFA and HDL-C. Tiopronin apparently ameliorated the hepatocyte degeneration and the infiltration of inflammatory cells in the livers, but UDCA did not affect the pathological features of the livers. Both tiopronin and UDCA ameliorated the mitochondrial abnormality in the livers. The benefits of tiopronin were associated with increased SOD and GSH-Px activities, and with decreased MDA activity and CYP2E1 expression in the livers. CONCLUSION: Tiopronin exerts protective effects against non-alcoholic steatohepatitis in rats, which may be associated with its antioxidant properties and regulation of lipid metabolism.

Leflunomide induces immunosuppression in collagen-induced arthritis rats by upregulating CD4+CD25+ regulatory T cells.

This study was to investigate the effect of leflunomide on the immunosuppressive CD4+CD25+ regulatory T cells (CD4+CD25+ Tregs) in collagen-induced arthritis (CIA) rats. CIA was induced by collagen type II in Wistar rats. Immunofluorescence flow cytometry and RT-PCR were used to determine the proportion of CD4+CD25+ Tregs and the expression of Foxp3 mRNA, respectively. Proliferation of T lymphocytes was assayed with MTT reagent, and the level of transforming growth factor beta1 (TGF-beta1) in the supernatant of concanavalin A (Con A)-induced T lymphocytes was determined by ELISA kit. Our investigations demonstrated that inhibition of arthritis by leflunomide was related to changes in CD4+CD25+ Tregs. In addition, A771726, which is the active metabolite of leflunomide, promoted the differentiation of spleen lymphocytes into CD4+CD25+ Tregs, increased antiinflammatory cytokine TGF-beta1 secretion, and adjusted the activity of Con A-induced lymphocytes in vitro.

Antiinflammatory and immunoregulatory effects of total glucosides of Yupingfeng powder.

BACKGROUND: Yupingfeng, a traditional Chinese complex prescription, has been used efficaciously in China for the cure and prevention of inflammatory diseases related to immunodeficiency such as allergic rhinitis and chronic bronchitis. However, the active components of this prescription remain unclear. The present study focused on investigating the antiinflammatory and immunoregulatory effects of the glucosidic extract from Yupingfeng. METHODS: We tested animal models for ear swelling induced by dimethylbenzene in mice; palm swelling induced by carregeenin and granuloma induced by cotton pellet in rats; level of haemolysin, antibody generation by the splenic cells, delayed hypersensitivity and T cell subsets in spleen of immunosuppressed mice. RESULTS: Glucosidic extract of 24 mg/kg, 48 mg/kg and 96 mg/kg significantly inhibited mice's ear swelling induced by dimethylbenzene. Similarly glucosidic extract of 16 mg/kg, 32 mg/kg and 64 mg/kg inhibited rats' palm swelling induced by carregeenin and granuloma induced by cotton pellet. Glucosidic extract of 24 mg/kg, 48 mg/kg and 96 mg/kg improved the IgM level in serum and level of haemolysin in splenocytes in mice immunosuppressed by cyclophosphamide. Delayed hypersensitivity in mice suppressed by cyclophosphamide was enhanced by glucosidic extract of 24 mg/kg, 48 mg/kg and 96 mg/kg. These results suggested that Yupingfeng could recover humoral and cellular immune function in mice with immunosuppression. Glucosidic extract of 48 mg/kg and 96 mg/kg significantly resisted the immunosuppressive mice ear swelling and maintained it at nearly normal level. The enhanced, delayed hypersensitivity actions of glucosidic extract, suppressed by cyclophosphamide, might be brought about by inducing TH cell and regulating T lymphocytes subset. CONCLUSIONS: The glucosidic extract from Yupingfeng has antiinflammatory and immunoregulation action, suggesting that these glucosides are the principal active components of the traditional Chinese prescription Yupingfeng.

Effect of oxymatrine on the p38 mitogen-activated protein kinases signalling pathway in rats with CCl4 induced hepatic fibrosis.

BACKGROUND: Recent studies have suggested that p38 mitogen-activated protein kinases (MAPK) signalling pathway plays an important role in hepatic fibrosis. This study explored the antifibrotic effect of oxymatrine on tetrachloromethane induced liver fibrosis in rats and its modulation on the p38 MAPK signalling pathway. METHODS: One hundred and twenty healthy male Sprague-Dawley rats were randomly assigned to six groups: normal (n = 20), induced fibrosis (n = 20), colchicine (n = 20) and three treatment groups of oxymatrine (n = 20 x 3). We obesrved changes in deposition of collagen, hyaluronic acid (HA), laminin (LN), collagen type IV (CIV), procollagen III (PCIII) and hydroxyproline (Hyp), a-smooth muscle actin (alpha-SMA) and phosphor-p38 (pp38). RESULTS: The relative indicators of changes in histopathology, HA, LN, CIV, PCIII, Hyp, alpha-SMA and pp38 were raised significantly in the induced fibrosis group (P < 0.01 vs normal group). The semiquantitative hepatic fibrosis staging scores of middle dose group and high dose group were decreased (P < 0.05 and P < 0.01 respectively vs the induced fibrosis group), as was the average area of collagen in rats' liver, the concentrations of serum HA, LN, CIV, PCIII and liver tissue homogenate Hyp. The gene expression of alpha-SMA mRNA was considerably decreased in the treated animals, as was the protein espression of pp38 protein. CONCLUSIONS: Oxymatrine is effective in reducing the production and deposition of collagen in the liver tissue of experimental rats in ways which relate to modulating the fibrogenic signal transduction via p38 MAPK signalling pathway.

Synergism of simvastatin with losartan prevents angiotensin II-induced cardiomyocyte apoptosis in vitro.

OBJECTIVES: Increasing evidence suggests that cardiomyocyte apoptosis has an important role in the transition from compensatory cardiac remodelling to heart failure. The synergistic effect of statins (3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors) and angiotensin II (Ang II) type 1 receptor antagonists reduces the incidence of cardiovascular events. However, the anti-apoptotic potential of the synergism between losartan and simvastatin in heart failure remains unexplored. Here, we demonstrate that Ang II-induced apoptosis is prevented by losartan and simvastatin in neonatal cardiomyocytes. METHODS: The in-vitro cardiomyocyte apoptosis model was established by co-culturing neonate rat cardiomyocytes with Ang II. Cell viability was analysed by the MTT assay. Cell apoptosis was evaluated using fluorescence microscopy and flow cytometry. Apoptosis-related proteins Bax and Bcl-2 expressions were measured by flow cytometry detection. KEY FINDINGS: Incubation with 10(-7) M Ang II for 48 h increased cardiomyocyte apoptosis and decreased cell viability. Losartan (10(-5) M) and simvastatin (10(-5) M), either alone or in combination, significantly decreased Ang II-induced cardiomyocyte apoptosis and increased cell viability. The q values calculated by the probability sum test were 1.31 for cardiomyocyte apoptosis and 1.21 for cell viability. Ang II induced a significant increase in Bax protein expression, whereas Bcl-2 protein expression was decreased. Losartan alone or in combination with simvastatin blocked the increased Bax expression and increased Bcl-2 expression. However, simvastatin had no such effect. CONCLUSIONS: Our data provide the first evidence that synergism of simvastatin with losartan prevents angiotensin II-induced cardiomyocyte apoptosis in vitro. Synergism between simvastatin and losartan may provide a new therapeutic approach to the prevention of cardiac remodelling.

[Effects of losartan and simvastatin on collagen content, myocardial expression of MMP-2 mRNA, MMP-9 mRNA and TIMP-1 mRNA, TIMP-2 mRNA in pressure overload rat hearts].

OBJECTIVE: To investigate the effects of simvastatin(Sim) and losartan(Los) on cardiac fibrosis and myocardial expression of MMP-2 mRNA, MMP-9 mRNA and TIMP-1 mRNA, TIMP-2 mRNA in pressure overloaded rat hearts. METHODS: The pressure overload model was induced by descending aortic constriction (DAC) in rats. SD rats were randomized into 6 groups (n = 20 each): normol control group, control sham group, DAC group, Los group (DAC + Los, 5 mg/kg), Sim group (DAC + Sim, 2 mg/kg), Los + Sim group (DAC + Los + Sim, Los 5 mg/kg, Sim 2 mg/kg). Water, Los or Sim drug was administrated by gavage daily beginning from day 5 after operation for 30 days. Collagen was measured on Masson stained myocardial sections, and the level of MMP-2 mRNA, MMP-9 mRNA and TIMP-1 mRNA, TIMP-2 mRNA in left ventricle were detected by RT-PCR. RESULTS: Collagen volume fraction (CVF) in DAC group was significantly higher than the normal control and sham groups (P < 0.01) which could be significantly reduced by Los and Sim (P < 0.05), especially in DAC + Los + Sim group (P < 0.01). The levels of myocardial MMP-2 mRNA, MMP-9 mRNA and TIMP-1 mRNA, TIMP-2 mRNA were also significantly higher in DAC group than in normal control and sham groups (P < 0.01). Treatment Sim and Los alone and especially in combination significantly decreased the TIMP-1 mRNA, TIMP-2 mRNA expressions (P < 0.01) while MMP-2 mRNA, MMP-9 mRNA levels remained unchanged (P > 0.05). CONCLUSION: Upregulation of myocardial MMP-2 mRNA, MMP-9 mRNA and TIMP-1 mRNA, TIMP-2 mRNA expressions might contribute to myocardial fibrosis in this model, Sim and Los significantly inhibited myocardial fibrosis possibly by downregulating myocardial TIMP-1 mRNA, TIMP-2 mRNA expressions in this model.

Preliminary study of total flavonoids from Litsea coreana Levl. on experimental adjuvant-induced arthritis in rats.

Litsea coreana Levl., a traditional Chinese medicine, has long been used for its diverse benefits such as detoxification and detumescence. Total flavonoids from Litsea coreana Levl. (TFLC) are the effective fraction of L. coreana. This study was designed to investigate the anti-inflammatory effects and mechanisms of TFLC against Feund's complete adjuvant (FCA)-induced arthritis in rats. Arthritis was evaluated by secondary paw swelling, polyarthritis index, body weight and histopathologic analysis. Con A- or LPS-stimulated splenocyte proliferation and cytokine (IL-1 and IL-2) production were assessed by MTT assay and activated mouse cell proliferation assay, respectively. The results indicate that therapeutic administration of TFLC (50, 100, 200 mg/kg, ig x 12 days) could significantly suppress secondary arthritis in rats with adjuvant-induced arthritis (AA). In vivo, TFLC (50, 100, 200 mg/kg, ig x 12 days) augmented splenocyte proliferation and increased IL-2 production in splenocytes, while reduced IL-1 activity in peritoneal macrophages (PM(Phi)) of AA rats. In vitro, TFLC at concentrations from 0.005 to 50 microg/ml exerted the same immunoregulatory effects on AA rats as those in vivo. In addition, an attractive feature of TFLC lies in its apparent lack of toxicity. These results suggest that TFLC without toxicity has a significant anti-arthritic effect on AA rats which could be associated with its anti-inflammatory and immunomodulatory properties.

Relative bioavailability and bioequivalence of metforphin hydrochloride extended-released and immediate-released tablets in healthy Chinese volunteers.

The aim of the present study was to investigate the relative bioavailability and bioequivalence of a new tablet formulation of metformin hydrochloride with reference to a standard product in healthy Chinese adult male volunteers. Two randomized, comparative, two-way crossover studies were therefore conducted. In study 1, which was a single-dose study, 20 subjects received 1000 mg metformin hydrochloride test product extended-release (MXR) tablets followed by the same amount of metformin hydrochloride reference product immediate-release (MIR) tablets with a 7-day washout period between the two doses. In study 2, which was a multiple-dose study, 22 subjects received MXR 1000 mg/d for 9 consecutive days followed by MIR 1000 mg/d with a 14-day washout period between the doses of the test and reference product. The serum metformin concentrations were monitored using a selective and sensitive high-performance liquid chromatography (HPLC) method with ultraviolet (UV) detection. The pharmacokinetic parameters were calculated using a 3P97 program. Analysis of variance (ANOVA) of the half-life of the absorption phase (t(1/2ka)), the half-life of the elimination phase (t(1/2ke)) and the mean retention time (MRT) and the Wilcoxon Signed Rank test of T(max) for the two preparations were significantly different. A significant difference was found in the ANOVA for C(max) in the single-dose study, while this was not the case in the multiple-dose study. Two one-sided t-tests showed that there were no significant differences in the area under the concentration-time curve (AUC) values between the two formulations. The present study indicates that the test preparation was bioequivalent to the reference preparation when both MXR and MIR were investigated in healthy Chinese adult male volunteers. And on the basis of the mean AUC(0-t), AUC(0-infinity) and AUC(ss), the relative bioavailability of the MXR was found to be 107.80%, 111.89% and 110.61% respectively compared with MIR.

Pharmacokinetics and tissue distribution of 5-fluorouracil encapsulated by galactosylceramide liposomes in mice.

AIM: To study the pharmacokinetics and tissue distribution of 5-fluorouracil encapsulated by galactosylceramide liposomes (5-Fu-GCL) in mice. METHODS: The concentration of 5-fluorouracil (5-Fu) in serum was detected by high performance liquid chromatography after 5-Fu-GCL (80, 40, 20 mg/kg) and free 5-Fu (40 mg/kg) were injected intravenously into mice. The tissue distribution of 5-Fu-GCL (40 mg/kg) and free 5-Fu (40 mg/kg) was investigated, and concentration-time profile of the two preparations in the liver were studied. Data were analyzed by 3p97 program. RESULTS: Serum concentration-time curves of 5-Fu-GCL and free 5-Fu conformed to one compartment model of first order absorption. 5-Fu-GCL at 80, 40, and 20 mg/kg had T(1/2Ke) of 25.8+/-4.2, 27.3+/-4.4, and 28.2+/-5.6 min; C0 of 24.9+/-4.9, 17.7+/-3.6, and 11.5+/-2.7 mg/L; and AUC of 990.0+/-45.2,622.5+/-38.3, and 340.4+/-25.6 mg x min x L(-1), respectively. In contrast free 5-Fu at 40 kg/mg had T(1/2Ke) of 15.8+/-2.2 min, C0 of 35.8+/-6.2 mg/L, AUC of 639.0+/-35.9 mg x min x L(-1). The tissue distribution of 5-Fu-GCL in the liver and immune organs was significantly increased, while in heart and kidney it was remarkably decreased. The AUC of 5-Fu-GCL in the liver was 3 times higher than that of free 5-Fu. CONCLUSION: The pharmacokinetics and tissue distribution of 5-Fu-GCL appears to be linear-related and dose-dependent, and exhibits sustained-release and hepatic target characteristics.

Gastroprotective effect and mechanism of amtolmetin guacyl in mice.

AIM: To investigate the gastroprotective effect and mechanism of amtolmetin guacyl (AMG, MED15) in mice. METHODS: Male and female Kunming strain mice, weighing 18-22 g, were utilized in the experiment. Normal or ethanol-induced gastric mucosal damage models in mice were successfully established to investigate the gastroprotective effect and mechanism of AMG. In the experiment of gastric mucosal damage after repeated treatment with AMG, the mice were randomly divided into 5 groups: normal group, 3 AMG groups receiving (75, 150 and 300 mg/kg), and tolmetin group receiving 90 mg/kg. The mice were randomly divided into 6 groups as follows: normal group, model group, AMG groups with doses of 75, 150 and 300 mg/kg, respectively, and tolmetin group with a dose of 90 mg/kg in ethanol-induced gastric mucosal damage experiment. The severity of gastric mucosal lesions was scored from 0 to 5. Gastric tissue sections were stained with hematoxylin and eosin (HE) and examined under light microscopy. Also gastric tissue sections were stained with uranyl acetate and lead citrate, and examined under electron microscopy. In addition, nitric oxide (NO) and malondialdehyde (MDA) contents, and nitric oxide synthase (NOS) and superoxide dismutase (SOD) activities in the stomach tissue homogenates were measured by biochemical methods. RESULTS: Repeated treatment with AMG (75, 150 and 300 mg/kg) for 7 d did not induce any appreciable mucosal damage, and the average score was not significantly different from that of normal mice. In contrast, tolmetin (90 mg/kg) produced significant gastric mucosal lesions compared with the normal group (P<0.01). AMG (75, 150 and 300 mg/kg) significantly reduced the severity of gastric lesions induced by ethanol in a dose-dependent manner as compared with the model group (P<0.05, AMG 75 and 150 mg/kg vs model; P<0.01, AMG 300 mg/kg vs model). Light and electron microscopy revealed that AMG (150 and 300 mg/kg) induced minimal changes in the surface epithelium layer, without vascular congestion or leucocyte adherence. AMG (75,150 and 300 mg/kg) demonstrated dose-dependent gastroprotective effects on mice in our study. AMG (75, 150 and 300 mg/kg) could significantly increase NO content and NOS level in the stomach homogenates of mice compared with the model group (P<0.05, AMG 75 mg/kg and 150 mg/kg groups vs model group; P<0.01, AMG 300 mg/kg vs model group) respectively. Moreover, AMG (150 and 300 mg/kg) not only significantly increased SOD activities but also obviously decreased the MDA content in the stomach homogenates of mice.