Modifications produced by selective inhibitors of cyclooxygenase and ultra low dose aspirin on platelet activity in portal hypertension.
World J Gastroenterol 2007;
13:5065-70. [PMID:
17876871 PMCID:
PMC4434635 DOI:
10.3748/wjg.v13.i38.5065]
[Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To study the mechanism involved in the potentially beneficial effect of ultra low dose aspirin (ULDA) in prehepatic portal hypertension, rats were pretreated with selective COX 1 or 2 inhibitors (SC-560 or NS-398 respectively), and subsequently injected with ULDA or placebo.
METHODS: Portal hypertension was induced by portal vein ligation. Platelet activity was investigated with an in vivo model of laser induced thrombus production in mesenteric circulation and induced hemorrhagic time (IHT). Platelet aggregation induced by ADP and dosing of prostanoid products 6-keto-PGF1α, TXB2, PGE2 and LTB4 were also performed.
RESULTS: The portal hypertensive group receiving a placebo showed a decreased in vivo platelet activity with prolonged IHT, an effect that was normalized by ULDA. SC-560 induced a mild antithrombotic effect in the normal rats, and an unmodified effect of ULDA. NS-398 had a mild prothrombotic action in portal hypertensive rats, similar to ULDA, but inhibited a further effect when ULDA was added. An increased 6-keto-PGF1α was observed in portal hypertensive group that was normalised after ULDA administration. TXA2 level after ULDA, remained unchanged.
CONCLUSION: These results suggest that the effect of ULDA on platelet activity in portal hypertensive rats, could act through a COX 2 pathway more than the COX 1, predominant for aspirin at higher doses.
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