Fractal analysis of rat dermal tissue in the different injury states.

Scar formation and chronic ulcers can develop following a skin injury. They are the result of the over- or underproduction of collagen. It is very important to evaluate the quality and quantity of the collagen that is produced during wound healing, especially with respect to its structure, as these factors are very important to a complicated outcome. However, there is no standard way to quantitatively analyse dermal collagen. As prior work characterised some potentially fractal properties of collagen, it was hypothesised that collagen structure could be evaluated with fractal dimension analysis. Small-angle X-ray scattering technology (SAXS) was used to evaluate the dermis of rats exposed to graft harvest, burn, and diabetic pathologic states. It was found that almost all collagen structures could be quantitatively measured with fractal dimension analysis. Further, there were significant differences in the three-dimensional (3-D) structure of normal collagen versus that measured in pathologic tissues. There was a significant difference in the 3-D structure of collagen at different stages of healing. The findings of this work suggest that fractal analysis is a good tool for wound healing analysis, and that quantitative collagen analysis is very useful for assessing the structure of dermal collagen.

Exploring nanoscale structure change of dermal tissues suffering injury by small angle X-ray scattering and transmission electron microscopy.

Scar formation and wound non-healing often occur during wound repair after skin injury, which are still unresolved. Clinic indicated that the structure played an important role in the wound repair. Our previous research showed that the wound over-healed (scar formation) when the integrity and continuity of dermal tissues was destroyed by injury. Other evidences showed that wound healing was impaired in diabetes because the underlying alternation in their skin tissues occurred caused by advanced glycation end products (AGES) aggregation. In order to explore the changes of the structure of skin at nanoscale, the small angle X-ray scattering (SAXS), compared with transmission electron microscopy (TEM), was applied to observe the skin in different pathological status. The results showed that there were some regular patterns in the structure of dermal tissue. The patterns were changed by different pathological status, which would result in wound healing disorder. These will be beneficial for clarifying the pathological mechanisms of wound healing.

Electroacupuncture improves low-grade duodenal inflammation in FD rats by reshaping intestinal flora through the NF-κB p65/NLRP3 pyroptosis pathway.

Electroacupuncture (EA) is an effective alternative for the treatment of functional dyspepsia (FD). It reduces low-grade duodenal inflammation and improves the symptoms of FD by downregulating the expression of NF-κB p65 and NLRP3, but its mechanism needs to be elucidated. To examine the regulatory effect of electroacupuncture (EA) on intestinal flora and NF-κB p65/NLRP3 pyroptosis pathway in FD rats. The FD rat model was established via multi-factor stress intervention for two weeks. The rats were randomly divided into the NC group, model group, NF-kB inhibitor group (NF-κB inhibitor BAY 11-7082 was administered), EA group, and EA + NF-kB inhibitor group. After 14 days of treatment, the rats were sacrificed, and the protein and mRNA levels of NF-κB p65, IκB, and NLRP3 in the duodenum were evaluated by Western blotting assays and real-time fluorescent quantitative PCR. The Illumina MiSeq sequencing platform was used to analyze the V4 region of the 16S rRNA gene of intestinal flora and predict functional genes. The concentration of short-chain fatty acids (SCFAs) in feces was assessed by metabolomics. EA can decrease low-grade duodenal inflammation and promote gastrointestinal motility in FD rats. This effect is mediated by inhibition of the NF-κB p65/NLRP3 pyroptosis pathway, an increase in the alpha and beta diversity of gut microbiota in the duodenum, an increase in the abundance of beneficial bacteria at the phylum and genus levels, and an increase in the content of SCFAs. The protective effect of EA against FD might involve multiple hierarchy and pathways. EA may remodel intestinal flora by inhibiting the NF-κB p65/NLRP3 pyroptosis pathway, thereby improving low-grade duodenal inflammation in FD rats.

Pellino1 orchestrates gut-kidney axis to perpetuate septic acute kidney injury through activation of STING pathway and NLRP3 inflammasome.

AIMS: Intestinal barrier dysfunction is the initial and propagable factor of sepsis in which acute kidney injury (AKI) has been considered as a common life-threatening complication. Our recent study identifies the regulatory role of Pellino1 in tubular death under inflammatory conditions in vitro. The objective of our current study is to explore the impact of Pellino1 on gut-kidney axis during septic AKI and uncover the molecular mechanism (s) underlying this process. MATERIALS AND METHODS: Immunohistochemistry (IHC) was conducted to evaluate Pellino1 and NOD-like receptor thermal protein domain associated protein 3 (NLRP3) levels in renal biopsies from critically ill patients with a clinical diagnosis of sepsis. Functional and mechanistic studies were characterized in septic models of the Peli-knockout (Peli1-/-) mice by histopathological staining, enzyme-linked immunosorbent assay (ELISA), flow cytometry, immunofluorescence, biochemical detection, CRISPR/Cas9-mediated gene editing and intestinal organoid. KEY FINDINGS: Pellino1, together with NLRP3, are highly expressed in renal biopsies from critically ill patients diagnosed with sepsis and kidney tissues of septic mice. The Peli1-/- mice with sepsis become less prone to develop AKI and have markedly compromised NLRP3 activation in kidney. Loss of Peli1 endows septic mice refractory to intestinal inflammation, barrier permeability and enterocyte apoptosis that requires stimulator of interferons genes (STING) pathway. Administration of STING agonist DMXAA deteriorates AKI and mortality of septic Peli1-/- mice in the presence of kidney-specific NLRP3 reconstitution. SIGNIFICANCE: Our studies suggest that Pellino1 has a principal role in orchestrating gut homeostasis towards renal pathophysiology, thus providing a potential therapeutic target for septic AKI.

Electroacupuncture regulates hepatic cholesterol synthesis by HMGCR deubiquitination in rats.

This experiment was designed to explore the effect and mechanism of electroacupuncture (EA) for hyperlipidemia and hepatic cholesterol synthesis in rats. Liver and adipose tissues were assessed histologically, and body and liver weight, serum and liver lipid levels, expression of mTOR/ubiquitin-specific peptidase 20 (USP20)/recombinant 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), and phosphorylation of mTOR and USP20 were measured. In vitro deubiquitination assays with liver cytosol were conducted. EA at Fenglong point ameliorated hyperlipidemia and hepatocyte steatosis, and decreased p-USP20, p-mTOR and HMGCR expression in the liver by reducing deubiquitination. Furthermore, EA decreased feeding-induced lipid biosynthesis in the liver. Concomitantly, EA prevented the induction of phosphorylated USP20 and mTOR, and HMGCR expression; and reduced the deubiquitination of HMGCR after re-feeding. This experiment demonstrated that EA can effectively improve hyperlipidemia and reduce hepatic cholesterol synthesis by counteracting the deubiquitination activity of HMGCR in hyperlipidemic rats.

Maternal Rumen Bacteriota Shapes the Offspring Rumen Bacteriota, Affecting the Development of Young Ruminants.

The maternal rumen microbiota can affect the infantile rumen microbiota and likely offspring growth, and some rumen microbes are heritable and are associated with host traits. However, little is known about the heritable microbes of the maternal rumen microbiota and their role in and effect on the growth of young ruminants. From analyzing the ruminal bacteriota from 128 Hu sheep dams and their 179 offspring lambs, we identified the potential heritable rumen bacteria and developed random forest prediction models to predict birth weight, weaning weight, and preweaning gain of the young ruminants using rumen bacteria as predictors. We showed that the dams tended to shape the bacteriota of the offspring. About 4.0% of the prevalent amplicon sequence variants (ASVs) of rumen bacteria were heritable (h2 > 0.2 and P < 0.05), and together they accounted for 4.8% and 31.5% of the rumen bacteria in relative abundance in the dams and the lambs, respectively. Heritable bacteria classified to Prevotellaceae appeared to play a key role in the rumen niche and contribute to rumen fermentation and the growth performance of lambs. Lamb growth traits could be successfully predicted using some maternal ASVs, and the accuracy of the predictive models was improved when some ASVs from both dams and their offspring were included. IMPORTANCE Using a study design that enabled direct comparison of the rumen microbiota between sheep dams and their lambs, between littermates, and between sheep dams and lambs from other mothers, we identified the heritable subsets of rumen bacteriota in Hu sheep, some of which may play important roles in affecting the growth traits of young lambs. Some maternal rumen bacteria could help predict the growth traits of the young offspring, and they may assist in breeding of and selection for high-performance sheep.

Duhuo jisheng decoction suppresses matrix degradation and apoptosis in human nucleus pulposus cells and ameliorates disc degeneration in a rat model.

ETHNOPHARMACOLOGICAL RELEVANCE: The lower back pain (LBP) caused by intervertebral disc (IVD) degeneration brings a heavy burden to society. A classic treatment method of Chinese medicine, fangji-duhuo jisheng decoction (DHJSD), has been effective in the clinical treatment of LBP, although the underlying mechanism remains unknown. AIM OF THE STUDY: In this work, the main objective was to study the effects of DHJSD on in vitro IVD degeneration of human nucleus pulposus (NP) cells after pressure treatment and on an in vivo interrupted IVD degeneration rat model. MATERIALS AND METHODS: The effects of DHJSD on the viability of NP cells were detected using Cell Counting Kit-8. RT-qPCR, western blotting, TUNEL assay, transmission electron microscopy, and immunofluorescence staining were performed to explore the molecular mechanism underlying protection against compression-induced matrix degradation and apoptosis in NP cells by DHJSD. Furthermore, the effects of DHJSD on IVD degeneration in a rat IDD model were also determined. RESULTS: We found that DHJSD increased the viability of NP cells in a concentration- and time-dependent manner. Furthermore, DHJSD significantly reduced compression-induced NP matrix degeneration and apoptosis, activated autophagy, and inhibited the p38/MAPK signaling pathway in NP cells subjected to compression. Autophagy inhibitor 3-MA and p38/MAPK signaling pathway activator anisomycin reversed the beneficial effects of DHJSD in NP cells, indicating that DHJSD protects against IVD degeneration by autophagy activation and P38/MAPK signaling pathway inhibition. Furthermore, DHJSD treatment effectively delayed IVD degeneration in a puncture-induced IDD rat model. CONCLUSIONS: DHJSD prevents compression-induced matrix degradation and cell apoptosis through regulating autophagy and the P38/MAPK signaling pathway. The mechanism underlying the effects of DHSJD elucidated in this study provides a new direction for LBP treatment.

Metatranscriptomics of the Hu sheep rumen microbiome reveals novel cellulases.

BACKGROUND: Cellulosic biomass has great potential as a renewable biofuel resource. Robust, high-performance enzymes are needed to effectively utilize this valuable resource. In this study, metatranscriptomics was used to explore the carbohydrate-active enzymes (CAZymes), especially glycoside hydrolases (GHs), present in the rumen microbiome of Hu sheep. Select CAZymes were experimentally verified and characterized after cloning and expression in E. coli. RESULTS: The metatranscriptomes of six Hu sheep rumen microbiomes yielded 42.3 Gbp of quality-checked sequence data that represented in total 2,380,783 unigenes after de novo assembling using Trinity and clustered with CD-HIT-EST. Annotation using the CAZy database revealed that 2.65% of the unigenes encoded GHs, which were assigned to 111 different CAZymes families. Firmicutes (18.7%) and Bacteroidetes (13.8%) were the major phyla to which the unigenes were taxonomically assigned. In total, 14,489 unigenes were annotated to 15 cellulase-containing GH families, with GH3, GH5 and GH9 being the predominant. From these putative cellulase-encoding unigenes, 4225 open reading frames (ORFs) were predicted to contain 2151 potential cellulase catalytic modules. Additionally, 147 ORFs were found to encode proteins that contain carbohydrate-binding modules (CBMs). Heterogeneous expression of 30 candidate cDNAs from the GH5 family in E. coli BL21 showed that 17 of the tested proteins had endoglucanase activity, while 7 exhibited exoglucanase activity. Interestingly, two of the GH5 proteins (Cel5A-h28 and Cel5A-h11) showed high specific activity against carboxymethylcellulose (CMC) and p-nitrophenyl-ß-d-cellobioside (pNPC) (222.2 and 142.8 U/mg), respectively. The optimal pH value for activity of Cel5A-h11 and Cel5A-h28 was 6.0 for both enzymes, and optimal temperatures were 40 and 50 °C, respectively. Both enzymes retained over 70 and 60%, respectively, of their original activities after incubation at 40 °C for 60 min. However, their activities were rapidly diminished upon exposure to higher temperatures. Cel5A-h11 and Cel5A-h28 retained more than 80 and 60% of their maximal enzymatic activities after incubation for 16 h in buffered solutions in the pH range from 4.0 to 9.0. CONCLUSION: The metatranscriptomic results revealed that the rumen microbiome of Hu sheep encoded a repertoire of new enzymes capable of cellulose degradation and metatranscriptomics was an effective method to discover novel cellulases for biotechnological applications.

[Effects of the cutaneous and blood contents of glucose on wound healing in diabetic rats with superficial partial thickness scalding].

OBJECTIVE: To study the effect of the cutaneous and blood contents of glucose on wound healing in diabetic rats with superficial partial thickness scalding. METHODS: 96 Sprague-Dawley rats were randomized into control group and STZ-induced diabetic group, inflicted with superficial partial thickness scalding of 10% TBSA on the back. The glucose content in the blood and wound tissue were evaluated before injury and at day 1, day 3, day 5, day 7, day 10 and day 14 after injury. Wound healing process in the rats was dynamically observed by naked eyes and histologically examined. The cell cycles of keratinocytes from wound site were determined before injury and at day 3, day 7 and day 10 after injury. RESULTS: The concentrations of blood glucose in diabetic wound was significant increased than normal group (27.28 mmol/L +/- 0.80 mmol/L vs. 4.65 mmol/L +/- 0.14 mmol/L, P < 0.01). The content of local glucose in wound tissue were significantly correlated with that in the blood (r = 0.881, P < 0.05). When compared with the control group, wound healing of the diabetic rats were delayed with the characteristics of impaired epithelialization and decreased. percentages of S stage and G(2)/M stages of keratinocytes. CONCLUSION: Local glucose content in diabetic wound was varied with blood glucose concentration. The increased glucose concentration in diabetic wound was attributed to the impaired wound healing in diabetes. High glucose concentration could inhibit the epithelialization and decrease the keratinocyte proliferation.

[Fibrosis after damage to fat dome structure of skin of pig].

OBJECTIVE: To observe the fibrosis of skin after damage to the fat dome structure in skin of pig. METHODS: Totally 4 pieces of skin grafts of intermediate thickness in the size of 5 cm × 5 cm were obtained from both sides beside the spine of back in each of the 4 female red Duroc pigs with pedicle on one side with Humby knife performed by burn specialists, who were rich in clinical experience. These skin grafts were assigned as thin dermis group (TD). Pedicled tissue grafts in the size of 5 cm × 5 cm with the thickness of 1.5 mm were obtained within the wounds resulted from former incision with the same method mentioned above, and these tissue grafts were set as fat dome group (FD). The above-mentioned two groups of skin grafts were sutured back in situ immediately after completion of the former procedures. On post surgery day (PSD) 7, 14, and 21, 5 wounds were respectively selected according to the random number table for gross observation of the surgical areas. Tissue samples were obtained from corresponding surgical area deep to the deep fascia after gross observation at above-mentioned time points. Some of the tissue samples were used for observation of distribution of collagen fibers in the regions of operation of both groups of skin grafts with HE staining, and the breadth of fibrosis was measured; some of the tissue samples were used for observation of distribution of type I or III collagen fibers in the regions of incision of both two groups of skin grafts with Sirius red staining. Data were processed with two independent sample t test. RESULTS: A little scab on the edge of wounds was observed on PSD 7; all the wounds were healed on PSD 14; a few hairs were observed growing in the surgical area on PSD 21. HE staining showed that traces of incision were observed in the superficial layer of dermis and at the junction between dermis and fat dome at each time point; profuse hyperplasia of collagen fibers with parallel and orderly arrangement were observed in the region of incision of skin grafts in groups TD and FD at each time point. The breadth of fibrosis of the region of incision of skin grafts was respectively (251 ± 31), (240 ± 3 7), and (342 ± 69) µm in group TD, (239 ± 36), (286 ± 61), and (332 ± 28) µm in group FD on PSD 7, 14, 21, without significantly statistical difference (with t values respectively 0.750, -1.971, and 0.375, P values above 0.05). Sirius red staining showed that large amount of type III collagen fibers and small amount of type I collagen fibers arranging parallelly were present in the region of incision of skin grafts in groups TD and FD at each time point. CONCLUSIONS: Under the circumstances of relatively intact restoration of dermal tissue, no excessive fibrosis was observed after simple incisional injury of fat dome in skin of pig.

Effect of necrotic tissue on progressive injury in deep partial thickness burn wounds.

OBJECTIVE: To evaluate the influence of necrotic tissue on progressive injury in deep partial thickness burn wounds. METHODS: Tissue specimens were cultured both for estimation of IL-8, EGF, bFGF, PDGF-AB and histopathological examination, from the pre-operation, post-operation, and non-operation wounds from seven patients with deep partial thickness burn. RESULTS: In seven specimens from the non-operation group, IL-8 release increased compared with those in the post-operation group (P < 0.001), while the levels of EGF, bFGF, PDGF-AB release were lower than those in the post-operation group. Histopathological examination revealed that in the non-operation group, the degree of neutrophil infiltration was enhanced, the extent of tissue necrosis enlarged, and residual skin appendages disappeared. In contrast, in the post-operation group, the degree of inflammatory response was decreased, with the formation of fresh granulation tissue and epithelialization. CONCLUSION: This study suggests that the presence of necrotic tissue could be the inhibitory factor in the wound healing process, as it might cause tissue progressive injury leading to the delay of wound healing. To promote wound healing, active tangential excision is recommended to remove necrotic tissue.

[Effects of advanced glycosylation end products on the biological behavior of neutrophils].

OBJECTIVE: To investigate the effects of advanced glycation end products (AGE) on the biological behavior of neutrophils in vitro, to look for the relationship between accumulation of AGE and abnormal inflammation in wound healing in diabetic mellitus patients. METHODS: Neutrophils were isolated from SD rats and incubated in vitro. The cells were divided into four groups according to different concentrations of AGE in cell suspension: control group (C, with treatment of RPMI - 1640), A group (with treatment of 0.315 mg/mL AGE + RPMI - 1640), B group (with treatment of 0.625 mg/mL AGE + RPMI - 1640), D group (with treatment of 1.250 mg/mL AGE + RPMI - 1640). Activity of neutrophils were determined by MTT colorimetric assay. Selectin-L mRNA expressions were analyzed by reversible transcription polymerase chain reaction (RT -PCR) technique. The levels of reactive oxygen species (ROS) in neutrophils were measured with DCFH-DA method. The protein concentration of neutrophil elastase (NE) was assayed by ELISA. RESULTS: The activity of neutrophils were obviously increased in A, B, and D groups when compared with that in C group [(0.170 +/- 0.040) in C group, (0.320 +/- 0.030) in A group, (0.380 +/- 0.020) in B group, (0.290 +/- 0.010) in D group, P <0. 05]. The expression of Selectin-L mRNA in A, B, D groups were significantly higher than that in C group (0.95 +/- 0.08, 1.36 +/- 0.27, 0.50 +/- 0.26.vs.0.36 +/- 0.26, P < 0.05. respectively). The ROS levels in A, B, D groups was markedly higher than that in C group (1.64 +/- 0.20, 2.16 +/- 0.26, 3.26 +/- 0.75. vs. 0.72 +/- 0.15, P <0.05, respectively). The levels of NE in A, B, D groups were significantly increased when compared with that in C group(1.98 +/- 0.43, 2.50 +/- 0.43, 2.01 +/- 0.18 vs 0.91 +/- 0. 21, P <0.05, respectively). CONCLUSION: AGE can enhance the activity of neutrophil, with change in cellular biological behaviors, which may be one of main reasons for abnormal inflammation in wounds of diabetes mellitus patients.

[Study of neovascularization disturbance in deep partial-thickness scald in rats with diabetes mellitus].

OBJECTIVE: To study the relationship between the degree of neovascularization and non-healing wounds in scalded rats with diabetic mellitus. METHODS: Sixty Sprague-Dawley rats were randomly divided into control group (C, n = 30, with treatment of isotonic saline) and streptozocin (STZ)-induced diabetic group (D, n = 30, with treatment of STZ), and then they were inflicted with 20% TBSA deep partial thickness scald. Wound specimens were harvested immediately after scald and on 1, 3, 7, 10, 14, 21 post scald days (PSD) to observe histological changes, and wound healing rates were calculated. Degree of neovascularization in wound (labeled with blue microsphere) and the quantity of vascular endothelial cells (labeled with red CD31) were also measured by double-labeling immunofluorescence. RESULTS: Compared with those in C group, Wound healing rate and histological value scores were lowered, and the degree of neovascularization was abated markedly at each time point. The degree of neovascularization in D group (12.00 +/- 1.40) was obviously lower than that in C group on 7 PSD (60.00 +/- 3.00, P <0.01). There was no obvious difference in the number of vascular endothelial cells in both groups, however, the majority of endothelial cells had not formed functional capillaries in D group. CONCLUSION: Vascular endothelial cell can proliferate actively with poor blood supply in diabetic nonhealing with deep partial-thickness scald wounds, but it is still poor in blood supply due to lack of functional capillaries.

[Study on the mechanism of scar formation: epidermis template defect theory].

Dermal defection and the degree of its loss determine the natural process of wound healing, which is the key reason leading to excess scar hyperplasia. The function of tri-dimensional structure in dermis acts as a template to regulate the properties of reparative cells. The template structure induces the reparative cells to grow into the structure which changes the skin mechanic status on wound area. Also, the component of extracellular matrix can affect behaviours of fibroblasts negatively or positively, for the reason that the structure of dermal tissue has a permissive effect on the dermal components in regulating behaviours of reparative cells. Therefore, the behaviors of cells depend on the structure of the template. The suitable tri-dimensional structure of dermis facilitates normal cell cycling. The more the structure of dermis closed to its physiological status, the better the biological behaviors of cells act. Moreover, the integrity as well as the continuity of dermal tissue is the prerequisite for serving as a template. The damage to the integrity and the continuity of dermal tissue may be one of the key reasons to lead abnormal tissue repair and scar formation. Thus, we hypothesize that the loss of dermal template may be one of the mechanism of abnormal scar formation and propose the theory of extracellular matrix framework deficiency or destruction.

[Influence of L-arginine supplementation on the plasma amino acid spectrum in burn patients].

OBJECTIVE: To explore the influence of L-arginine supplementation on the plasma amino acid spectrum in burn patients. METHODS: Ten burn patients were randomly divided into burn control (n = 5, with compound 14 amino acid injection accounting for 2% of the total caloric value), and experimental (n = 5, with intravenous injection of L-arginine which accounted for 2% of total caloric value) groups. The intake of other nutrients for these two groups of patients was the same. The nutrient regimen was begun on the 3 PBD, with one quarter of the daily supply. On 4 and 5 PBD, one half of the daily supply was given, and from 6 to 21 PBD full supplementation was given. Venous blood samples were collected on 3, 7, 14, 21 and 28 PBD for the determination of plasma levels of amino acids. Ten normal volunteers served as normal control. RESULTS: The plasma level of citrulline in both groups was significantly lower than normal value (P < 0.05) on 3 PBD before L-arginine supplementation. There was no obvious difference in plasma levels of ornithine and arginine in the two groups on 3 PBD compared with normal value (P > 0.05). The plasma level of ornithine, citrulline and arginine in burn control group declined on 3 PBD. The plasma level of arginine in experimental group on 14, 21 and 28 PBD were 280 +/- 121 micromol/L, 223 +/- 106 micromol/L and 110 +/- 44 micromol/L, respectively, which were significantly higher than those in burn control group (124 +/- 21 micromol/L, 59 +/- 15 micromol/L, 50 +/- 26 micromol/L). The plasma level of ornithine (30 +/- 5 micromol/L) and citrulline (162 +/- 44 micromol/L) on 21 PBD in experimental group were markedly higher than those in burn control group (8 +/- 7 micromol/L, 66 +/- 4 micromol/L, P < 0.05 or 0.01). There was no difference in the plasma levels of other amino acids at all postburn time points between the two groups (P > 0.05). CONCLUSION: The production process of L-arginine from citrulline was accelerated after burns. The plasma levels of L-arginine, ornithine and citrulline were increased markedly after L-arginine supplementation, while that of other amino acids was not influenced. The pharmacological effects of L-arginine may be related to the promotion of ornithine cycle.

[Influence of tangential excision within 24 postburn hours on the local wound inflammatory response in patients with deep partial thickness burn].

OBJECTIVE: To investigate the influence of early tangential excision within 24 postburn hours on local wound inflammatory response and tissue injury in patients with deep partial thickness burn. METHODS: Twelve patients with deep partial thickness burn were enrolled in the study. Tangential excision was performed within 24 postburn hours. The same wound of a patient was divided into three areas for harvesting tissue samples, i.e. pre-operation, post-operation and non-operation areas. For each patient, the biopsies from the pre-operation area were harvested before tangential excision, while those from post-operation and non-operation areas were harvested during 5 to 7 postburn days (PBDs). The contents of IL-8, MPO and MDA in wound tissue were determined by tissue culture and chemical colorimetry, respectively. HE and Mason's staining were employed to assess the degree of necrosis of the wound tissue. RESULTS: The IL-8, MPO and MDA contents in the local wound tissue after tangential excision were 6.83 +/- 1.85 microg/L, 4.07 +/- 0.87 U/g, and 8.94 +/- 5.66 micromol/g, respectively, which were significantly lower than those from non-operation area (P < 0.01). The inflammatory response in the non-operative wound area was distinct with expansion of necrotic tissue area. In contrast, the local inflammatory response of the wound after tangential excision was ameliorated without the enlargement of necrotic tissue area. CONCLUSION: Tangential excision within 24 postburn hours could be beneficial in ameliorating local inflammatory response, and in preventing progressive deepening of the burn wounds, thus it could accelerate wound healing in patients with deep partial thickness burn.

[An experimental study on the effects of postburn dietary supplementation of enhanced nutrients].

OBJECTIVE: To evaluate the effects of postburn dietary supplementation of arginine (Arg), omega-3 polyunsaturated fatty acid (omega-3PUFA) and glutamine (Glu) on the metabolism, immunology and wound healing in scalded rats. METHODS: Thirty Sprague-Dawley (SD) rats inflicted with 30% total body surface area deep partial thickness scald on the back after the gastrostomy catheter was placed were employed as the model. The rats were randomly divided into A and B groups, and all of them received continuous isonitrogenous (25% protein, 12% fat, 63% carbohydrate), isocaloric (175 kcal/kg/day), and isovolemic intragastric tube feedings. The contents of Arg, omega-3PUFA, Glu in the dietary of B group were enriched. The parameters were measured on the 10th day after injury, including the response of spleen cells to ConA, the plasma levels of PGE(2), IL-2, albumin, transferrin, glucagons, cortisol in blood, the urinary content of vanillylmandelic acid (VAM) in 24-hour urine, the content of hydroxyproline, the ratio of type I to type III collagen in burn wounds, and the nitrogen content in the liver and in the jejunal mucosa, as well as the weight changes, skin delayed hypersensitivity test, and wound healing time. RESULTS: It was revealed that the serum level of albumin, the nitrogen content in the liver and in the jejunal mucosa were obviously higher in B than those in A group. At the same time, there was no statistical difference in the plasma levels of cortisol and glucagons and urinary content of VAM between the two groups, nor in body weight changes. Meanwhile, the response of spleen cells to ConA and the skin delayed hypersensitivity induced by DNFB 14 days after injury in group B were also enhanced compared with those in group A. Although the expression of PGE2 from peritoneal macrophages was lower, the content of hydroxyproline from burn wounds in group B was significantly higher than that in group A, and the ratio of type l to type III collagen in group B was significantly lower than that in group A. Compared with group A, the wound healing time in group B was significantly shortened (P < 0.05). CONCLUSION: The low-fat and high-protein feeding diet with enriched arginine, omega-3 PUFA, glutamine could benefit the nutritional status after burn injury, thus improve the immunological function and promote wound healing.

[Establishment of an animal model with hypertrophic scar].

OBJECTIVE: To establish an animal model of hypertrophic scar on the rabbit ears and to observe the dynamic process of scar formation on the ventral side of the rabbit ears. METHODS: Full skin defect (2 cm x 5 cm in diameter) was created on the ventral side of 60 ears in 32 New Zealand white rabbits. 1% silver sulfadiazine cream was applied to the wounds, and the dressing was changed once a week till wound healing. Four ears without operation were taken as control. Wound healing under natural condition was observed continuously for 12 months after the operation. The scar proliferation on the rabbit ears was observed by light microscope and transmission electron microscope, and the scar index was determined by computer image analyzing system. RESULTS: The color, thickness and texture of the wounds on the rabbit ears after epithelization underwent a process of scar overgrowth, maturation and degeneration. The change in scar index was in accordance with the wax and wane of scar proliferation. CONCLUSION: The hypertrophic scar formed on the ventral side of rabbit ears after natural healing of full thickness skin wounds was similar to that in humans. The results indicated that this animal model was ideal for the study of the developmental mechanism of hypertrophic scars and for the evaluation of the efficacy of the prevention and treatment of hypertrophic scars.

[Histological observation of the effects of tangential excision within twenty-four postburn hours on the progressive injury of the progression of deep partial thickness burn wound].

OBJECTIVE: To evaluate the effects of early tangential excision on the prevention of the progression of deep partial thickness burn wound. METHODS: Twelve burn patients with deep partial thickness burn wound were enrolled and received tangential excision of the burn wound within 24 postburn hours (PBHs). The histological samples were harvested from the wound before and 5 - 7 postoperative days (PODs) after the operation and the wound without operation 5 - 7 postburn days (PBDs). The samples were observed by means of HE staining, Masson's staining and the labelling of Vimentin antigen positive cells by immunohistological skill. RESULTS: The inflammatory reaction of the burn wound without operation aggravated progressively along with that of disease and the tissue necrosis area enlarged. And the residual skin appendages disappeared due to the enhanced inflammatory reaction. The brown area expanded and light green area shrinked by Masson's staining. The Vimentin antigen positive cell count decreased significantly. But in the burn wound being performed tangential excision within 24 PBHs, focal inflammatory reaction exhibited evident ligher than that in burn wound without operation. Moreover, there appeared fresh granulation formation and partial epithelial coverage with no enlarged necrotic tissue area in the operated wound when compared with that in non-operated wound (P < 0.05). Furthermore, the light green area exhibited no obvious shrinking by Masson's staining and the Vimentin antigen positive cell count was much more in the operation area than that in non-operative area (P < 0.05). CONCLUSION: It might be beneficial to the host to perform tangential excision within 24 PBHs, which could remove burn wound necrotic tissue in time and hamper the progression of tissue degenerative injury. The healing process of deep partial thickness burn wound was therefore accelerated.