[Protective effects of snake venom antimicrobial peptide OH-CATH on E. coli induced rabbit urinary tract infection models].

To investigate the potential protective effects of the snake venom antimicrobial peptide OH-CATH, we used a series of rabbit urinary tract infection models successfully induced by cephalosporin-resistant E.coli and E. coli ATCC 25922. The experimental models were administered saline, snake venom antimicrobial peptide OH-CATH, Cefoperazone and Sulbactam through the urethra. Urine was collected on days 1, 5, 10 and 14 after model establishment and urine culture was done to check the infection in each experimental animals. On day 14, all the animals were sacrificed and the bladder tissue specimens were taken for observation by H-E staining light microscope and transmission electron microscope. We found that the snake venom antimicrobial peptide OH-CATH reduced bacterial count in urine culture in both cephalosporin-resistant E. coli and the E. coli ATCC 25922 infected animals, while Cefoperazone and Sulbactam were only able to reduce the positive rate induced by the E. coli ATCC 25922 but had no obvious effects on animal model induced by cephalosporin-resistant E. coli strains (P<0.05). We also found less necrosis, degeneration and inflammatory cell infiltration in bladder tissue in OH-CATH groups as compared with the other experimental groups. The snake venom antimicrobial peptide OH-CATH had stable antibacterial activity against cephalosporin-resistant E. coli and E. coli ATCC 25922 and exhibited protective effects on both the cephalosporin-resistant E. coli and E. coli ATCC 25922 rabbit urinary tract infection models, suggesting that the molecule may have potential clinical applications in treating urinary tract infections.

[Construction of tissue engineering bone with bone marrow stromal cell sheets].

OBJECTIVE: To construct tissue engineering bone with bone marrow stromal cell (BMSC) sheets of dogs. METHODS: BMSC were derived from dog bone marrow and cell sheets were prepared with temperature-responsive dishes after the cells were induced by osteogenesis. Allogeneic dogs decalcification bone matrixes (DBM) were prepared. Sixteen dogs were divided into 4 groups. The MSC cell sheets-rhBMP-2-BMSC-DBM were implanted under the left latissimus dorsi myofascial as the experimental side; while the rhBMP-2-BMSC-DBM were implanted in the right side as the control. Ectopic bone formation in vivo was evaluated by histological examination 4, 8, 12, 16 weeks after operation. RESULTS: The osteogenesis in the experimental group was better than that in the control group. New bone area in the experimental side was larger than that in the control group, and the difference was significant (P < 0.05). After 16 weeks, lamellar bone was connected into a film in the experimental group. Haversian system and red bone marrow could be seen. CONCLUSIONS: BMSC cell sheets could promote the bone formation of functional tissue-engineered bone.