Targeted metabolomics of urinary biomarkers in rats with osteoarthritis / 中华地方病学杂志

ABSTRACT

Objective:Rat osteoarthritis (OA) model with different experimental cycles was established, analysis of small molecule metabolites in urine were carried out, in order to study the OA biomarkers and/or biomarker clusters with disease and/or the severity of disease indicator function.Methods:Using random number table method, sixty male SPF sprague-dawley (SD) rats weighing 300 - 350 g were randomly divided into model group and control group according to their body weights with 30 rats in each group. The experimental cycles were 4, 8 and 12 weeks, respectively. Rat OA model was established by modified Hulth method. At the end of each experiment, knee joint tissue and urine samples were collected. The knee joint histopathological slides were used to observe modeling situation under light microscope. High performance liquid chromatography quadrupole ion trap tandem mass spectrometer [HPLC-(Q-TRAP)-MS/MS] was used to quantitatively detect the candidate substance in the urine of rats. SPSS 20.0 was used to process and analyze the measurement data. Wilcoxon rank-sum test was used for comparison between groups. Python 3.0 was used to plot the receiver operator characteristic (ROC) curve. P < 0.05 was considered to be statistically significant. Results:Histological observation showed that in model group, the joint space narrowed or disappeared, the cartilage became thinner, damaged or extensively exfoliated. The chondrocytes were degenerated, necrotic or absence. With the extension of the experimental cycles, the lesions worsened. Targeted metabolomics study found that 7 different metabolites were screened at 4 weeks, namely fumaric acid, succinic acid, oxaloacetic acid, malic acid, cis-aconite acid, α-ketoglutaric acid and sulfoalanine. Sulfoalanine was low expressed in model group and other 6 organic acids were high expressed ( P < 0.05). At 8 weeks, a total of 12 different metabolites were screened, including histidine, lysine, tyrosine, tryptophan, threonine, valine, leucine, aspartic acid, creatinine, α-ketoglutaric acid, oxaloacetic acid and malonyl carnitine, all of them were highly expressed in model group ( P < 0.05). At 12 weeks, a total of 4 different metabolites were screened, among which sulfoalanine, cysteine and sarcosine were low expressed in model group, and succinic acid was high expressed ( P < 0.05). Conclusions:Typical OA pathology changes and disease progress in the rats of model group are exhibited, the model is established successfully. The urinary small molecular metabolite profiles of OA rats with different disease progress are different, mainly organic acids and amino acids. The metabolites related to urinary tricarboxylic acid cycle and essential amino acids can be used as biomarker clusters of OA.