OBJECTIVETo reproduce a reliable rat model of burn with infection for the study of prevention and treatment of infected wound.

METHODS(1) Electrical burn producing apparatus equipped with constant temperature (80°C) and pressure (0.5 kg) was used to reproduce burn injury (with area of 4.5 cm(2)) on both sides of the back in 50 SD rats for different duration (4, 6, 8, 10, 12 s), with 10 rats for each burn duration. On post burn day (PBD) 1, gross condition of wounds was observed with naked eyes. Wounds on the left side were used to observe healing time. The wounds on the right side were used for histological observation to determine the depth of injury, and they were classified into superficial and deep partial-thickness injury. (2) Another 36 SD rats were divided into A (inflicted with superficial partial-thickness burn, n = 18) and B (inflicted with deep partial-thickness burn, n = 18) groups according to the random number table. Rats in both groups were treated in accordance with method of preliminary experiment. Immediately after burn, 0.1 mL of liquid containing 1 × 10(9), 1 × 10(7), 1 × 10(5) CFU Pseudomonas aeruginosa (PA) ATCC 27853 was respectively inoculated to the wounds on one side (with 6 rats for each amount), while the wounds on the other side were treated with the same volume of normal saline as control. Inflammatory reaction of wounds was examined with HE staining on post inoculation day (PID) 1. On PID 1, 2, 3, 5, 7, and 14, the number of subeschar bacteria was respectively counted and the bacteria were identified with Gram stain and biochemical reaction. Wound healing time was recorded. Data were processed with t test.

RESULTS(1) Burn for 6, 8 s was respectively identified as injury time resulting in superficial or deep partial-thickness injury according to histological observation and wound healing time. (2) Obvious inflammatory cell infiltration was observed in the wounds in B group which were inoculated with 1 × 10(7), 1 × 10(9) CFU PA, and the infiltration was less marked in A group with inoculation of 1 × 10(9) CFU PA. (3) The bacteria isolated from wounds of A and B groups was identified as PA. The subeschar bacteria count within PID 14 in A group, in which different amount of PA was inoculated, was mostly less than 1 × 10(5) CFU/g of tissue, while that in B group in which 1 × 10(9) CFU PA was inoculated was more than 1 × 10(5) CFU/g of tissue. (4) There was no obvious difference in wound healing time between wounds inoculated with different amount of PA and wounds treated with normal saline in A group (with t value respectively 1.26, 0.29, 1.07, P values all above 0.05). Wound healing time of wounds in B group, in which 1 × 10(9) CFU PA was inoculated, was longer as compared with that treated with normal saline [(22.5 ± 1.0) d vs. (19.4 ± 1.6) d, t = 2.73, P < 0.05].

CONCLUSIONSIn rat, deep partial-thickness burn wound inoculated with 1 × 10(9) CFU PA ATCC 27853 is a reliable model with high reproducibility for the study of infection of burn wound.

Animals ; Burns ; microbiology ; Disease Models, Animal ; Male ; Rats ; Rats, Sprague-Dawley ; Wound Infection ; microbiology

Altitude ; Animals ; Bacteria ; classification ; genetics ; Feces ; microbiology ; Gastrointestinal Microbiome ; Hypoxia ; microbiology ; Male ; Rats, Sprague-Dawley

OBJECTIVESTo investigate the mechanism of the Chinese medicine theory that Fei (Lung) and Dachang (Large Intestine) are exteriorly and interiorly related via synchronous observation on the dynamic changes of the respiratory and intestinal microflora.

METHODSForty specific pathogen free Sprague-Dawley rats were selected and randomly divided into blank (10 rats) and chronic bronchitis model groups (30 rats). The blank group rats were put into the smoke-free environment and the model group rats were put into the smoke environment in order to establish pulmonary disease (chronic bronchitis) model. Then the corresponding changes of the respiratory and intestinal microflflora of the model on 20th, 50th and 70th days were synchronously observed.

RESULTSThe respiratory tract microflflora showed an increase in the total aerobic and Staphylococcus aureus and reduced anaerobic amount signifificantly on 20th day in the respiratory tract microflflora (P<0.05 or 0.01). On 50th day, total aerobic, total anaerobic amount and bififidobacterium signifificantly increased (P<0.05). On 70th day, Staphylococcus aureus reduced and lactobacillus increased signifificantly (P<0.01). The intestinal microflflora showed an increase in the total aerobic, Clostridium perfringens, enterobacter and enterococcus significantly increased on 20th day (P<0.05 or 0.01). Staphylococcus aureus on 50th day increased significantly (P<0.05). Total aerobic and enterococcus increased, total anaerobic and Clostridium perfringens reduced signifificantly on 70th day (P<0.05 or 0.01).

CONCLUSIONThe microecosystem of respiratory tract and intestine of rat model during the pathological process showed a dynamic disorder, indicating an interaction between the lung and large intestine which may be one of the connotations as they exteriorly and interiorly related.

Animals ; Bronchitis, Chronic ; microbiology ; pathology ; Disease Models, Animal ; Gastrointestinal Microbiome ; Intestines ; microbiology ; Lung ; microbiology ; Male ; Rats, Sprague-Dawley ; Time Factors

OBJECTIVETo study the effects of different perioperative treatments on the number and proportion of gut flora in SD rats.

METHODSForty-eight SD rats were randomized into 8 groups including the control group, antibiotics group, bowel preparation group, fasting group, antibiotic-bowel preparation group, antibiotics-bowel preparation-fasting group, bowel preparation-surgery-antibiotics-early postoperative feeding group (early feeding group), and bowel preparation-surgery-antibiotics-postoperative fasting group. The rats were sacrificed and stool specimens were collected from the cecum. Stools were diluted and transferred to selective medium. Bacteria counts were calculated after 48 hours of culture under constant temperature. The changes in gut flora between the different groups were compared in terms of E.coli, Bacteroides, Bifidobacterium, and Enterococcus.

RESULTSCompared with the control group, the total bacteria, Bacteroid, Enterococcus, Bifidobacterium were all significantly decreased(P<0.05), while the E.coli count and the bacillus/coccus ratio were significantly elevated(P<0.05). In the bowel preparation group, the total bacteria count, Bacteroid, Enterococcus, Bifidobacterium were all significantly decreased(P<0.05), while the E.coli count remained stable(P>0.05) and the bacillus/coccus ratio was significantly elevated(P<0.05). In the fasting group, the total bacteria count, Bacteroid, Enterococcus, Bifidobacterium were all significantly decreased(P<0.05), while the E.coli count remained stable(P>0.05) and the bacillus/coccus ratio was significantly elevated(P<0.05). Early postoperative feeding increased E.coli, Enterococcus, and total bacteria count(P<0.05), and lowered bacillus/coccus ratio(P<0.05) as compared to the fasting group.

CONCLUSIONSAntibiotics, bowel preparation, and fasting have influence on the gut flora of SD rats in count and bacillus/coccus ratio, leading to dysbiosis. Early postoperative feeding may improve dysbiosis.

Animals ; Feces ; microbiology ; Male ; Microbiota ; Perioperative Care ; methods ; Rats ; Rats, Sprague-Dawley

This paper is to explore changes of intestinal mucosal barrier, intestinal flora, and bacterial translocation in rats with severe acute pancreatitis (SAP). Twenty four male SD rats were randomly divided into the control group (n = 10) and the experimental group (n = 14). The model of severe acute pancreatitis of rats was induced by the method of injecting adversely 5% sodium taurocholate into the common biliary-pancreatic duct. All of the rats were killed after 24 hours and the level of the serum amylase and the plasma endotoxin was determined after that. The pathological changes of pancreas and small intestine were observed through hematoxylin-eosin staining (HE staining) and the abdominal viscera bacterial translocation rates were tested. With the method of real-time polymerase chain reaction (RT-PCR) the quantity of the intestinal flora was analyzed. In the control group, the level of Escherichia coli, Lactobacillus and Bifidobacterium were 2.08 ± 1.29, 11.04 ± 7.55 and 12.21 ± 4.95, respectively. On the contrast, the level of Escherichia coli in the cecum contents was much higher (9.72 ± 3.58, P < 0.01), while the Lactobacillus number was decreased significantly (0.67 ± 0.34, P < 0.01), and the Bifidobacterium number was also decreased (4.59 ± 3.42, P < 0.05) in the experimental group, so the ratio of Bifidobacterium/Escherichia coli was reversed. Besides, in the experimental group, the plasma endotoxin positive rates and the bacterial translocation rates were much higher (P < 0.01 or P < 0.05) and the pathology scores of pancreas and small intestines were also significantly higher (P < 0.01) than those in the control group. These results indicated that in severe acute pancreatitis rats, the intestinal mucosal barrier was severely damaged and the dysbacteriosis occurs in the intestinal canal. And these might relate to the occurrence and development of multiple organ infection.
Animals ; Bacterial Translocation ; Endotoxins ; Intestinal Mucosa ; pathology ; Intestines ; microbiology ; Male ; Pancreas ; pathology ; Pancreatitis ; microbiology ; pathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the dynamic variability of intestinal flora and endotoxins in rats with fulminate hepatic failure.

METHODSEstablishing the fulminate hepatic failure models by intraperitoneal injection of Galactosamine. Forty Sprague-Dawley rats were divided into three groups: group A (n=10) were killed at the beginning of the experiment as control; while Group B (n=12) and C (n=18), the fulminate hepatic failure models, were killed 24 and 48 hours respectively after successful induction. Then, the contents of the jejunum, ileum and colon descendents were collected and a quantitative analysis was made about intestinal flora. Meanwhile, the concentrations of endotoxin in portal vein and right ventricle were determined and so were those in contents of ileums and colons.

RESULTSOur experiments showed that the livers of rats in group B were injured most seriously among three groups, and a minor recovery of hepatic function was observed in group C with the decrease of total bile acids (P< 0.05). Analysis on intestinal flora show: the intestinal enterobacteriacea increase and the lactobacillus decrease in group B (P< 0.01 in jejunum and ileum and P<0.05 in colon). The comparisons between group C and B showed that the enterobacteriacea in the former decreased in both jejunum and colon (P< 0.05) while the number of lactobacillus recovered in the jejunum of group C (P<0.05). Quantitative analysis on endotoxins showed that the ileum endotoxin increased in group B (P< 0.05) and in group C, endotoxins in ileum and colons also increased (vs. control, P<0.01); portal endotoxin in group B showed higher level than that in group A and C (P< 0.01).

CONCLUSIONThe alteration of intestinal flora was observed in fulminate hepatic failure rats. Abnormal intestinal flora might lead to incline of endotoxin in ileum, colon and portal vein, while the recovery of normal intestinal flora would decrease the level of portal endotoxin.

Animals ; Bacteria ; isolation & purification ; Endotoxins ; analysis ; Intestines ; chemistry ; microbiology ; Liver ; physiopathology ; Liver Failure ; microbiology ; Male ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the preventive and treatment effects of smectite powder on enteral bacterial translocation in scalded rats.

METHODSFifty-four Sprague-Dawley (SD) rats were randomly divided into three groups, i.e. normal control (A, n = 6), burn control (B, n = 24), and burn treatment (T, n = 24) groups. The rats in B and T groups were fed with tracing bacteria JM109, which was transfected with PUC19 plasmid in advance. The rats were subjected to 30% TBSA scald injury after the plasmid was shown to have colonized in the intestine. Smectite powder (0.6 g/day/kg) was fed to rats of T group immediately after the scalding, while those in B group received no smectite powder. Bacterial translocation in blood and mesenteric lymph nodes in all groups was observed and identified by enzyme digestion at 12 post scald hour (PSH) and on 1, 3 and 5 post-scald days (PSD). The contents of malondialdehyde (MDA) and superoxide dismutase (SOD) were determined in rat intestinal tissue. And the degree of injury to the entire small intestine was observed pathologically. The villus height of intestinal mucosa was measured, and the rate of epithelial nuclear splitting of mucosal crypts was calculated.

RESULTSThe number of rats with positive blood bacterial culture in B group was obviously higher than that in A and T groups (P < 0.05) on 1 and 5 PSD. The bacterial quantity in mesenteric lymph nodes (MLN) in T group on 1 PSD (38 +/- 16 CFU/g) and 5 PSD (68 +/- 20 CFU/g) were obviously lower than those in B group (228 +/- 67 vs 183 +/- 29 CFU/g, P < 0.05). There was significant difference in the intestinal contents of MDA and SOD between B and T groups at each time point (P < 0.05). The rat jejunum villus height and the epithelial nuclear splitting in the small intestine mucosa in T group were evidently higher than those in B group (P < 0.05 or 0.01).

CONCLUSIONSmectite powder is beneficial to the protection of the intestinal mucosa in scalded rats, and can effectively prevent postburn intestinal bacterial translocation in rats.

Animals ; Bacterial Translocation ; Burns ; drug therapy ; microbiology ; Intestinal Mucosa ; microbiology ; pathology ; Rats ; Rats, Sprague-Dawley ; Silicates ; therapeutic use

BACKGROUNDBroad-spectrum antibiotic administration promotes intestinal colonization of exogenous fungal pathogens in healthy animals and has been recognized as one of the risk factors of invasive fungal infection in clinical settings. It is unclear whether broad-spectrum antibiotic treatment would change the intestinal mycobiota without exogenous fungal challenge in the context of sepsis.

METHODSWe established a rat model of double-hit sepsis using burn injury and endotoxin challenge. Rats with burn injury or double-hit sepsis received imipenem treatment for 3 days or 9 days, and their colon contents were sampled for selective fungal culture and isolation counts.

RESULTSImipenem treatment promoted the overgrowth of the commensal fungus Geotrichum capitatum in rats with burn injury. Imipenem treatment also promoted colon colonization by exogenous fungi in rats with burn injury and double-hit sepsis, including Trichosporon cutaneum, Candida albicans, Candida krusei, and Candida glabrata. A longer duration of imipenem treatment had a stronger impact on colon colonization by exogenous fungi.

CONCLUSIONImipenem treatment facilitates the overgrowth of commensal fungi and colonization by exogenous, potentially pathogenic fungi in the colons of rats with burn injury or double-hit sepsis.

Animals ; Anti-Bacterial Agents ; therapeutic use ; Burns ; complications ; microbiology ; Candida ; pathogenicity ; Colon ; microbiology ; Imipenem ; therapeutic use ; Male ; Rats ; Rats, Sprague-Dawley ; Sepsis ; drug therapy ; microbiology ; Trichosporon ; pathogenicity

Molecular karyotyping was applied to Pneumocystis carinii(Pc) from two strains of experimental rats, Sprague Dawley(SD) and Fisher(F), in Korea. Field inversion gel electrophoresis and contour clamped homogeneous electric field electrophoresis resolved 15 chromosomal bands from the Pc. The size of the bands was estimated 270kb to 684kb from SD rats, and 273kb to 713 kb from F rats. The bands of 283 kb from SD rats and of 273 kb from F rats stained more brightly suggesting duplicated bands. Total number of chromosomes was at least 16, and total genomic size was estimated 7 x 10(6) bp. All of the bands from F rats hybridized to the probe of repeated DNA sequences of Pc and the band of 448 kb size was proved to contain rDNA sequences, but Pc. chromosome bands from SD rats showed no reactions to the probes. The 2 different karyotypes of P. carinii from 2 strains of rats were maintained consistently for 2 years.
Electrophoresis- ; ; Korea- ; ; Nucleic-Acid-Hybridization ; Pneumocystis-carinii-isolation-and-purification ; Rats- ; *Karyotyping- ; ; *Pneumocystis-carinii-genetics ; *Rats,-Inbred-F344-microbiology ; *Rats,-Sprague-Dawley-microbiology

OBJECTIVE: To observe the effect of acupuncture at "Baihui" (GV 20), "Zhongwan" (CV 12) and "Zusanli" (ST 36) on intestinal flora in rats with stress gastric ulcer (SGU) , and to explore the mechanism of acupuncture promoting SGU recovery. METHODS: Thirty-one SPF SD rats were randomly divided into a control group (7 rats), a model control group (8 rats), an acupuncture group (8 rats) and a medication group (8 rats). The rats in the model group, acupuncture group and medication group were selected to applied the improved restraint water-immersion stress method to establish the SGU model. After modeling, the rats in the control group and model group were fixed and restrained for 20 min every day for a total of 5 days; the rats in the acupuncture group were intervented with acupuncture at "Baihui" (GV 20), "Zhongwan" (CV 12) and "Zusanli" (ST 36), once a day, 20 min each time, and twisting needle for 30 s every 5 min for a total of 5 days; the rats in the medication group were gavaged by solution of omeprazole enteric-coated tablet (200 mg/mL), 2 mL for each rat, once a day. Guth method was used to calculate the gastric mucosal damage index (GMDI), HE staining was used to observe the pathological changes of gastric mucosa, and 16SrDNA identification was used to detect the structural abundance of intestinal flora. RESULTS: Compared with the control group, the GMDI of rats in the model group was increased (<0.01), the gastric mucosal pathological changes were significant, and the intestinal flora richness index Chao1, Observed species and diversity index Shannon were all decreased (<0.05), the diversity index Simpson was increased (<0.05). Compared with the model group, the GMDI of rats in the acupuncture group and medication group was reduced (<0.01, <0.05), the gastric mucosal damage degree was reduced, and the intestinal flora richness index Chao1, Observed species and diversity index Shannon were all increased (<0.05) and the diversity index Simpson decreased (<0.05). Compared with the medication group, the GMDI of rats in the acupuncture group was reduced (<0.01), the recovery of gastric mucosal injury was better than that of the medication group. CONCLUSION Acupuncture can effectively improve gastric mucosal injury of SGU, and the mechanism may be related to increasing the diversity of intestinal flora and promoting the correction of the disordered intestinal flora.
Acupuncture Points ; Acupuncture Therapy ; Animals ; Gastrointestinal Microbiome ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Stomach Ulcer ; microbiology ; therapy