Changing laws of serum high mobility group box 1 protein in septic rats and the intervention effect of xuebijing / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To investigate the changing laws of serum high mobility group box 1 protein (HMGB1) in septic rats and intervention effect of Xuebijing on it.</p><p><b>METHODS</b>Lipopolysaccharide (LPS) (5 mg/kg BW) was intravenously injected into the tail vein of healthy male Wistar rats to prepare the sepsis rat model. In Experiment 1: 50 Wistar rats were randomly divided into three groups, i.e., the normal group (A, n=10); the LPS model group (B, n=10), the LPS +Xuebijing treatment group (C, n=30). Rats in the C group were further divided into three subgroups, i.e., 2 h before LPS injection (group C1), 2 h after LPS injection (group C2), and 8 h after LPS injection (group C3), 10 in each group. Blood samples were collected from the caudal vein to detect serum HMGB1 levels by Western blot at 4, 12, 24, 48, and 72 h after LPS injection. Experiment 2: 30 Wistar rats were equally divided into the LPS model group (D) and the LPS + Xuebijing treatment group (E), 15 in each group. They were treated as rats in the B group and the C1 group respectively. Five rats were sacrificed at 12, 24, and 48 h after LPS injection in the two groups. Blood as well as the tissue samples were harvested to measure such indices as ALT, AST, Cr, and BUN, as well as pathological changes of liver, lung, and kidney.</p><p><b>RESULTS</b>(1) Compared with the A group, serum HMGB1 levels were higher at various time points in the B group (P < 0.05). Compared with the B group, serum HMGB1 levels at 12,24,48, and 72 h decreased in the C1, C2, and C3 groups. Besides, the decrease was more obvious at 24 h and 48 h.The decrement in the C3 group was less than that in the C1 and C2 groups (P < 0.05). (2) In the D group, ALT, AST, Cr, and BUN were significantly higher than those in the A group and reached the peak at 24 h (P < 0.05). Compared with the E group, AST, Cr, and BUN at 24 and 48 h, and ALT at each time point decreased significantly in the E group (P < 0.05). (3)The results of pathological section of liver, lung, and kidney showed local congestion and hemorrhage, cell edema/necrosis/degeneration, infiltration of inflammatory cells, damage of characteristic structures and so on; particularly serious lesion occurred at 24 and 48 h in the D group. The microscopic lesion was obviously alleviated in the E group than in the D group at corresponding time points.</p><p><b>CONCLUSIONS</b>The serum HMGB1 levels increased in septic rats, with late occurrence of peak value and longer duration of the high value. HMGB1 played an important role in excessive inflammatory response and multiple organ dysfunction. Xuebijing could reduce the serum levels of HMGB1, improve biochemical parameters, and attenuate severe inflammatory response of liver, lung, and kidney tissues in septic rats. Besides, the earlier use, the better effect obtained.</p>

[Screening of strain producing an novel esterase with high enantioselectivity and molecular cloning of the enzyme gene].

A novel strain producing an enantioselective lipolytic enzyme was isolated from soil samples, and identified as Pseudomonas putida NH33. A genomic library of P. putida NH33 was constructed and screened for esterase activity in E. coli. One positive clone was isolated, and subsequent analyses of the plasmid by restriction mapping revealed a 4.7kb DNA fragment carrying esterase gene. The nucleotide sequence of the DNA was found to contain an open reading frame of 1142 nucleotides encoding esterase of 381 amino acid residues and designated PPEst. The primary structure of the esterase exhibited 35%-40% homology to those of related enzymes from various sources and 80%-90% homology to esterases from the genus Pseudomonas. Amino acid sequence deduced from the nucleotide sequence contains of the consensus active site sequence, GXSXG, of serine esterase. The PPEst fragments were cloned into the expression vector pET-22b( + ) and transformed into E. coli BL21 (DE3), and the recombinant protein fused with 6 x His at its C-terminus was purified to homogeneity by a single immobilized metal ion affinity chromatographic step. The molecular mass of the esterase was determined to be approximately 42kDa by SDS-PAGE. The purified enzyme could convert ethyl esters of 2-arylpropanoic acid to S-isomer of 2-arylpropanoic acids with an optical purity of > 99%. The result suggests that this esterase is excellent biocatalyst for synthesis of chiral pharmaceuticals. The enzyme is an novel esterase, and its nucleotide sequence has been submitted to GenBank under accession number AY896293.