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| Author(s): |
Vanessa Moreira
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI) |
| Defense date: | 2007-09-18 |
| Examining board members: |
Catarina de Fatima Pereira Teixeira;
Paulina Sannomiya;
Cristoforo Scavone;
Andreimar Martins Soares;
Ana Marisa Chudzinski Tavassi
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| Advisor: | Catarina de Fatima Pereira Teixeira |
| Abstract | |
Action of the phospholipase A2 (PLA22): myotoxins (MTs) -II and -III, from Bothrops asper (BaV) and CB2, from Crotalus durissus terrificus (CdtV) and these venoms on cyclooxygenases (COXs) and synthesis of prostaglandins (PGs) E2 and D2 were studied in vivo and in vitro. Intraperitoneal injection of sPLA22s and BaV but not CdtV released PGD2 and PGE2. MTs and BaV but neither CB2 nor CdtV induced expression of COX-2 by leukocytes. Release of PGs and expression of COX-2 occurred in vitro after incubation of macrophages (M?s) with PLA2 and neutrophils (N?) and M?s with BaV. CB2 induced only PGs release. Inhibition of cytosolic PLA2 (cPLA2), reduced PG levels caused by MTs, but not by CB2 while did not affect MTs-induced COX-2 expression. Involvement of NF-kB in COX-2 was showed using with inhibitors. In conclusion MTs, CB2 and BaV stimulate the synthesis of PGs in vivo and in vitro and MTs and BaV, but not CB2, induce COX-2 expression. VCdt does not affect these parameters. Effect of MTs on COX-2 is mediated by NF-kB, and on PGs by cPLA2. Effects of CB2 on PGs are independent of cPLA2 and OX-2. Since MT-II lacks catalytic activity the PLA2 activity per se is not relevant for activation of this cascade. (AU) | |