Quantitation of arachidonic acid metabolites in small tissue biopsies by reversed-phase high-performance liquid chromatography

Arachidonic acid metabolites exert a variety of distinct biological effects on the initiation and resolution of inflammatory diseases and their measur ements in tissue can be critical to evaluate their regulatory function duri ng the course of inflammation and to supplement in vitro experiments. The a im of this study was the detection and quantitative analysis of four arachi donic acid metabolites in small-sized biopsies of human periodontal tissues . The biopsies were homogenized and injected directly into a single analyti cal column of a RP-HPLC System. Detection was performed by a photodiode arr ay detector. Calibration was established by dilutions of authentic standard s of prostaglandin E2 (PGE2), leukotriene B4 (LTB4), 12(R)-hydroxy-5,8,10,1 4-eicosatetraenoic acid (12-HETE), and 15(S)-hydroxy-5,8,11,13 eicosatetrae noic acid (15-HETE). A total of 38 specimens weighing between 19 and 191 mg (wet tissue) were analyzed (mean = 59.9 +/- 30.2 mg). The detection limits were 1 pg for LTB4 and 12-HETE, 0.5 pg for 15-HETE, and 10 ng for PGE2. Th e concentrations of PGE2 and LTB4 were significantly higher in inflamed tha n in healthy periodontal tissues (P = 0.0079; P = 0.0114). 12-HETE was dete cted in one biopsy (30 pg/g); 15-HETE was not detected. This method of homo genization, extraction, and analysis of arachidonic acid metabolites by RP- HPLC appears to be well suited for studies of human oral biopsies. Only sma ll tissue samples and minimal laboratory equipment were required for a sens itive analysis, (C) 2000 Academic Press.