Department of Anatomy, University of Pécs, Szigeti u 12, 7624, Pécs, Hungary.
J Mol Neurosci. 2011 Jan;43(1):67-75. doi: 10.1007/s12031-010-9428-8. Epub 2010 Jul 30.
Oxidative stress plays an important role in various renal and hepatic pathologies, and reduction of oxidative stress-induced processes is an important protective strategy in tissues of diverse origins against harmful stimuli. Pituitary adenylate cyclase activating polypeptide (PACAP) is a well-known cytotrophic and cytoprotective peptide. PACAP promotes cell survival in numerous cells and tissues exposed to various stimuli. Protective effects of PACAP have been shown in the kidney, but it is not known whether PACAP is protective against oxidative stress in renal cells. Little is known about the effects of PACAP in the liver. The aim of the present study was to investigate whether PACAP is protective against oxidative stress in primary rat kidney cell culture and whether PACAP has any effect on cell survival in human WRL-68 hepatocytes and HEP-G2 hepatocellular carcinoma cells subjected to oxidative stress. Cells were exposed to various concentrations of H(2)O(2) with or without PACAP co-treatment and cell viability was evaluated with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide test (MTT). We found that oxidative stress induced a significant decrease in cell viability in both cell lines. PACAP could dose-dependently increase the percentage of living cells in kidney cells, but it failed to do so in hepatocytes. Given the survival-promoting effects of PACAP against oxidative stress in rat kidney, we conducted a further experiment to determine whether PACAP influences the markers of oxidative stress in vivo. We have proven earlier that PACAP was effective in kidney ischemia/reperfusion injury in vivo. In the present study, we determined the levels of the oxidative stress marker malondialdehyde and the activity of the scavenger molecules glutathione (GSH) and superoxide dismutase (SOD) following kidney ischemia/reperfusion in rats. We found that PACAP significantly increased the level of GSH and counteracted the marked reduction of SOD activity after ischemia/reperfusion in vivo. In summary, the present study showed that while PACAP was able to significantly increase the cell survival in primary kidney cell cultures exposed to oxidative stress, possibly involving interaction with the endogenous scavenger system, it failed to influence the viability of normal or cancerous hepatocytes.
氧化应激在各种肾脏和肝脏疾病中起着重要作用，减少氧化应激诱导的过程是各种来源的组织针对有害刺激的重要保护策略。垂体腺苷酸环化酶激活肽（PACAP）是一种众所周知的促细胞存活和保护肽。PACAP 可促进许多细胞和组织中暴露于各种刺激下的细胞存活。已经在肾脏中显示出 PACAP 的保护作用，但尚不清楚 PACAP 是否对肾细胞的氧化应激具有保护作用。关于 PACAP 在肝脏中的作用知之甚少。本研究旨在探讨 PACAP 是否对原代大鼠肾细胞培养中的氧化应激具有保护作用，以及 PACAP 是否对暴露于氧化应激的人 WRL-68 肝细胞和 HEP-G2 肝癌细胞的细胞存活有任何影响。细胞用不同浓度的 H₂O₂处理，或用 PACAP 共同处理，并通过 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四唑溴化物试验（MTT）评估细胞活力。我们发现，氧化应激在两种细胞系中均导致细胞活力显著下降。PACAP 可剂量依赖性地增加肾细胞中存活细胞的百分比，但对肝细胞则无效。鉴于 PACAP 在大鼠肾脏中对氧化应激具有促生存作用，我们进行了进一步的实验以确定 PACAP 是否影响体内氧化应激标志物。我们之前已经证明，PACAP 在体内肾缺血再灌注损伤中有效。在本研究中，我们在大鼠肾缺血再灌注后测定了氧化应激标志物丙二醛的水平以及清除分子谷胱甘肽（GSH）和超氧化物歧化酶（SOD）的活性。我们发现，PACAP 可显著增加 GSH 的水平，并拮抗体内缺血再灌注后 SOD 活性的显著降低。总之，本研究表明，虽然 PACAP 能够显著增加暴露于氧化应激的原代肾细胞培养物中的细胞存活率，可能涉及与内源性清除系统的相互作用，但它未能影响正常或癌细胞的活力。
