12(S)-HEPE

Abstract

Jieduquyuziyin prescription (JP), a traditional Chinese medicine (TCM) prescription, has been widely used for the clinical treatment of systemic lupus erythematosus (SLE). However, the complex chemical constituents of JP and the multifactorial pathogenesis of SLE make research on the therapeutic mechanism of JP in SLE challenging. In this paper, a serum metabolomics approach based on rapid resolution liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (RRLC-Q-TOF/MS) was employed to acquire the metabolic characteristics of serum samples obtained from mice in the SLE model group, JP-treated group, prednisone acetate (PA)-treated group and control group. The orthogonal partial least squares (OPLS) was applied to recognize metabolic patterns, and an obvious separation of groups was obtained. Thirteen metabolites, namely, phosphatidylethanolamine (PE 20:3), hepoxilin B3, lyso- phosphatidylethanolamine (lyso-PE 22:6), 12S-hydroxypentaenoic acid (12S-HEPE), traumatic acid, serotonin, platelet-activating factor (PAF), phosphatidylcholine (PC 20:5),eicosapentaenoic acid (EPA), 12(S)-hydroxyei- cosatetraenoic acid (12S-HETE), 14-hydroxy docosahexaenoic acid (14-HDOHE), lyso-phosphatidylcholine (lyso-PC 20:4), and indole acetaldehyde, were identified and characterized as differential metabolites involved in the pathogenesis of SLE. After treatment with JP, the relative content of 12(S)-HETE, PAF, 12(S)-HEPE, EPA, PE (20:3), Lyso-PE(22:6), and 14-HDOHE were effectively regulated, which suggested that the therapeutic effects of JP on SLE may involve regulating disturbances to the metabolism of unsaturated fatty acid, tryptophan and phospholipid. This research also demonstrated that metabolomics is a powerful tool for researching complex disease mechanisms and evaluating the mechanism of action of TCM.

Raw herbal medicines and JP extract

The following raw herbal medicines were purchased from the Chinese Herbal Medicine Co. Ltd. of Zhejiang Chinese Medical University (Hangzhou, China). JP was a combination of dried root of Radix Rehmanniae, Carapax Trionycis, Herba Artemisiae Annuae, Rhizoma Cimicifugae foetidae, Herba Hedyotidis, Radix Paeoniae Rubra, Herba Centellae Asiaticae, Semen Coicis, Fructus Citri Sarcodactylis and Radix Glycyrrhizae (at ratios of 5∶4∶4∶9∶5∶4∶5∶5∶3∶2). Next, 120 g JP was cut into small pieces and soaked in water (1/10 w/v) for 1 h, then boiled for 2 h. The filtrate was collected and the residue was extracted again with the same volume of water for another 2 h. The filtrates were combined and concentrated under vacuum to make a 1200 mL volume of JP.

Animals and treatments

40 female C57BL/6J mice, 8 weeks old and weighing 22 to 26 g, were purchased from the Experimental Animal Center of Zhejiang Chinese Medical University and were housed in four cages. The mice were housed in a specific-pathogen-free (SPF) environment and had free access to a standard diet and tap water. All animals were kept in an animal room with suitable conditions: temperature at 20 ± 2°C, relative humidity at 55% ± 10%, and 12 h dark-to-light cycle. All animals were allowed to acclimate for 1 week before the experiment. The mice were randomly divided into four groups (n = 10): JP-treated group, PA-treated group, SLE model group, and control group; and JP-treated group, PA-treated group, SLE model group were given a single 0.5 mL intraperitoneal injection of pristine (Sigma-Aldrich, Louis, MO, USA). JP and PA were given orally (daily) to JP-treated group and PA-treated group, respectively, from 1 month after pristane injection and continued till 5 months . PA was dissolved in physiological saline as a concentration of 0.69 mg mL−1, and the dosage was 18 mL kg−1 per day. The dosage of JP was also 18 mL kg−1 per day, and the SLE model group and control group were administered orally with an equivalent volume of physiological saline.