| 摘要: | 最近的研究顯示介白質-10(interleukin-10, IL-10)可作為內生性解熱原，並可逶過抑制發炎性細胞激素如介白質-1β((interleukin-1β, IL-1β)，介白質-6（IL-6）及腫瘤壞死因子(tumor necrosis factor-α, TNF-α)而來調控脂多醣(lipopolysaccharide, LPS)所引起之發燒反應。除了致熱性細胞激素(pyrogenic cytokines)外，證據顯示其他內生性物質，特別是麩胺酸(glutamate）、氫氧自由基(hydroxyl radicals)、前列腺素E2 (prostaglandin E2, PGE2)都被認為之發燒有關。就我們所知，目前對於IL-10減少LPS之發燒反應是否經由抑制兔子下視丘麩胺酸-氫氧自由基-前列腺素E2之途徑，仍然所知有限。因此，本研究將探討IL-10是否經由抑制靜脈注射LPS誘導下視丘麩胺酸、氫氧自由基、前列腺素 E2之產生，而達到解熱作用。主要是利用先前埋於兔子下視丘前視區(preoptic region of anterior hypothalamus, POAH)之微透析探針來收集細胞外之透析物。氫氧自由基之測量則是利用水楊酸鹽(salicylate)可和氫氧自由基形成穩定的2, 3-二基苯甲酸(2, 3-dihydroxybenzoic acid, 2, 3-DHBA)之特性，來測量下視丘中2, 3- DHBA，以代表氫氧自由基之量，而麩胺酸則利用高效液體層析法(high performance liquid chromatography, HPLC)結合螢光偵測器來測量；前列腺素E2之濃度是以酵素連接免疫吸附法(enzyme-linked immunosorbent assay, ELISA)來測量。而且，我們將進一步利用electrophoretic mobility shift assay（EMSA）及西方墨點法探討IL-10減少下視丘前列腺素E2之產生是否經由抑制NF-kB活化及向下調控下游環氧化酶-2 (cyclooxygenase-2, COX-2)蛋白表現所致。因此，本研究計畫結果將可揭露IL-10可能透過抑制LPS在兔子下視丘誘導產生之麩胺酸、氫氧自由基及前列腺E2，而達到解熱作用。
Recent reports have shown that interleukin-10 (IL-10) functions as an antipyretic in the regulation of fever to lipopolysaccharide (LPS) by inhibiting the synthesis of proinflammatory cytokines, including interleukin 1β(IL-1β), IL-6 and tumor necrosis factor-α(TNF-α). Besides pyrogenic cytokines, evidence has accumulated to suggest that other endogenous compound particular glutamate, hydroxyl radicals, and PGE2 have been considered to be involved in the genesis of pyrogenic fever. To our knowledge, little is known about that the LPS-induced fever could be reduced by IL-10 via inhibiting of glutamate-hydroxyl radical-prostaglandinE2 (PGE2) pathway in the rabbit’s hypothalamus. Therefore, the present study will attempt to determine whether IL-10 exerts its antipyresis by suppressing overproduction hypothalamic concentration of glutamate, hydroxyl radicals, and PGE2 induced by peripheral administration of LPS in rabbits. The extracellular dialysates in the preoptic region of the anterior hypothalamus (POAH) will be collected using a microdialysis probe previously placed in the brain region. The salicylate trapping method will be used to detect hydroxyl radicals by measurement of the stable product 2,3-dihydroxybenzoic acid (2,3-DHBA), whereas the glutamate release in the anterior hypothalamus of rabbit brain will be measured by high performance liquid chromatography (HPLC) in combination with a fluorescence detector. The concentration of PGE2 in the extracellular dialysate will be detected by enzyme-linked immunosorbent assay (ELISA) kits. In addition, we will use electrophoretic mobility shift assay (EMSA) as well as western blot to determine whether IL-10 reduces LPS-induced hypothalamic level of PGE2 may act through inhibiting NF-B activation and down regulation of cyclooxygenase-2 (COX-2) protein expression in the anterior hypothalamic tissue. The results obtained from this proposal should unveil that IL-10 may exert its amelioration of LPS-induced fever by inhibiting the glutamate, hydroxyl radical and PGE2 production in the rabbit’s hypothalamus. |
