[Establishment and applicability comparison of four models of acute liver ischemia/reperfusion injury in rat].

OBJECTIVE: To clarify the preparation methods of four rat models of liver ischemia/reperfusion injury (IRI) and to determine a liver IRI animal model that is consistent with clinical conditions, has stable pathological and physiological injury, and is easy to operate. METHODS: A total of 160 male Sprague-Dawley (SD) rats were randomly divided into four groups using an interval grouping method: 70% IRI (group A), 100% IRI (group B), 70% IRI with 30% hepatectomy (group C), and 100% IRI with 30% hepatectomy (group D), with 40 rats in each group. Each model was further divided into sham operation group (S group) and ischemia groups of 30, 60, and 90 minutes, with 10 rats in each group. After surgery, the survival status and awakening time of the rats were observed, and the liver lobectomy weight, bleeding volume, and hemostasis time of groups C and D were recorded. Blood samples were collected by cardiac puncture after 6 hours of reperfusion for determination the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), blood urea nitrogen (BUN), serum creatinine (SCr), and γ-glutamyl transpeptidase (γ-GT) in the serum to assess liver and kidney function. Hematoxylin-eosin (HE) staining and immunohistochemical staining of macrophages were performed to analyze the liver tissue structure damage from a pathological perspective. RESULTS: Rats in group A exhibited earlier awakening and acceptable mental status, while rats in the other groups showed delayed awakening and poor mental status. The hemostasis time in group D was approximately 1 second longer than that in group C. The mortality of rats subjected to 60 minutes of 70% hepatic ischemia was 0. Compared to the sham operation group, rats in each experimental group showed significant increases in serum levels of AST, ALT, ALP, BUN, SCr, and γ-GT, indicating impaired liver and kidney function in the rat models of liver IRI. In groups A, B, and C, the 90-minute ischemia subgroup exhibited more pronounced elevation in AST, ALT, ALP, BUN, SCr, and γ-GT levels compared to the 30-minute ischemia subgroup [AST (U/L): group A, 834.94±56.73 vs. 258.74±18.33; group B, 547.63±217.40 vs. 277.67±57.92; group C, 930.38±75.48 vs. 640.51±194.20; ALT (U/L): group A, 346.78±25.47 vs. 156.58±13.25; group B, 408.40±138.25 vs. 196.80±58.60; group C, 596.41±193.32 vs. 173.76±72.43; ALP (U/L): group A, 431.21±34.30 vs. 315.95±15.64; group B, 525.88±62.13 vs. 215.63±17.31; group C, 487.53±112.37 vs. 272.46±92.33; BUN (U/L): group A, 18.35±5.63 vs. 14.32±2.30; group B, 30.21±4.55 vs. 17.41±8.14; group C, 20.50±3.64 vs. 15.93±3.22; SCr (U/L): group A, 27.47±8.91 vs. 22.37±5.66; group B, 43.60±15.57 vs. 36.80±7.95; group C, 63.81±20.24 vs. 42.47±7.03; γ-GT (U/L): group A, 15.64±3.57 vs. 6.82±1.48; group B, 9.28±1.91 vs. 5.62±1.21; group C, 10.98±3.18 vs. 5.67±1.10; all P < 0.05]. The 100% IRI 90-minute group and 100% IRI 90-minute group with 30% hepatectomy exhibited more pronounced increases in the above-mentioned indicators compared to the corresponding 70% IRI control group, indicating increased liver and kidney damage in rats subjected to combined blood flow occlusion and hepatectomy. HE staining showed clear liver tissue structure with intact and orderly arranged cells in the sham operation group, while the experimental groups exhibited cell structure damage, including cell rupture or collapse, cell swelling, nuclear pyknosis, deep cytoplasm staining, cell shedding, and necrosis. The interstitium showed infiltration of inflammatory cells. Immunohistochemical staining revealed a higher number of macrophages in the experimental groups compared to the sham operation group. CONCLUSIONS: Four models of liver IRI in rat were successfully established. As the duration and severity of hepatic ischemia increased, liver cell ischemia worsened, leading to increased hepatocellular necrosis and exhibiting characteristic features of liver IRI. These models can effectively simulate liver IRI following liver trauma, with the group subjected to 100% ischemia and 30% hepatectomy showing the most severe liver injury. The designed models are reasonable, easy to perform, and exhibit good reproducibility. They can be used for investigating the mechanisms, therapeutic efficacy, and diagnostic methods related to clinical liver IRI.

Alcohol-Soluble Electron-Transport Materials for Fully Solution-Processed Green PhOLEDs.

Two alcohol-soluble electron-transport materials (ETMs), diphenyl(4-(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl)phosphine oxide (pPBIPO) and (3,5-bis(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl)diphenylphosphine oxide (mBPBIPO), have been synthesized. The physical properties of these ETMs were investigated and they both exhibited high electron-transport mobilities (1.67×10-4 and 2.15×10-4  cm2 V-1 s-1 ), high glass-transition temperatures (81 and 110 °C), and low LUMO energy levels (-2.87 and -2.82 eV, respectively). The solubility of PBIPO in n-butyl alcohol was more than 20 mg mL-1 , which meets the requirement for fully solution-processed organic light-emitting diodes (OLEDs). Fully solution-processed green-phosphorescent OLEDs were fabricated by using alcohol-soluble PBIPO as electron-transport layers (ETLs), and they exhibited high current efficiencies, power efficiencies, and external quantum efficiencies of up to 38.43 cd A-1 , 26.64 lm W-1 , and 10.87 %, respectively. Compared with devices that did not contain PBIPO as an ETM, the performance of these devices was much improved, which indicated the excellent electron-transport properties of PBIPO.

Molecular characterization and expression analysis of dihydroflavonol 4-reductase (DFR) gene in Saussurea medusa.

Dihydroflavonol 4-reductase (DFR), which catalyzes the reduction of dihydroflavonols to leucoanthocyanins, is a key enzyme in the biosynthesis of anthocyanidins, proanthocyanidins, and other flavonoids of importance in plant development and human nutrition. This study isolated a full length cDNA encoding DFR, designated as SmDFR (GenBank Accession No. EF600682), by screening a cDNA library from a red callus line of Saussurea medusa, which is an endangered, traditional Chinese medicinal plant with high pharmacological value. SmDFR was functionally expressed in yeast (Saccharomyces cerevisiae) to confirm that SmDFR can readily reduce dihydroquercetin (DHQ) and dihydrokampferol (DHK), but it could not reduce dihydromyricetin (DHM). The deduced SmDFR structure shared extensive sequence similarity with previously characterized plant DFRs and phylogenetic analysis showed that it belonged to the plant DFR super-family. SmDFR also possessed flavanone 4-reductase (FNR) activity and can catalyze the conversion of eridictyol to luteoforol. Real-time PCR analysis showed that the expression level of SmDFR was higher in flowers compared with both leaves and roots. This work greatly enhances our knowledge of flavonoid biosynthesis in S. medusa and marks a major advance that could facilitate future genetic modification of S. medusa.

Quality evaluation of snow lotus (Saussurea): quantitative chemical analysis and antioxidant activity assessment.

Snow lotus is commonly used as a medicinal plant and has great pharmacological value. To protect these endangered plants, in vitro propagation and cell cultures have been established in order to meet the growing market demand. The phenolic composition, antioxidant activities, total phenolic content (TPC) and total flavonoid content (TFC) from three most commonly used species, in vitro propagated lines and the cell cultures were investigated to qualify their pharmacological value. Quantitative analysis showed that the phenolics varied greatly among different species and the same species at different habitats. From this it can be inferred that the phenolics were influenced by genetic background and the environmental conditions. Significant correlations were observed between the antioxidant activity and several phenolics/TPC/TFC, suggesting that the phenolics are a major contributor of the antioxidant activity and are important for quality evaluation of snow lotus. Based on the abundance of phenolics, TPC, TFC and antioxidant activity, the order of the quality for wild species would be Saussurea involucrata > Saussurea medusa > Saussurea gossypiphora. For S. medusa, its quality judged by origin would be Shigatse > Lhasa > Nagqu. For in vitro propagated plants, the matured plants could be a reliable substitute for wild plants, and the dynamics of phenolics is critical for quality control of this monocarpic species. We provide the first report of quality comparison between the wild plants and the cell cultures. The advantages of developing cell cultures as alternatives for plants collected from the wild are discussed.