Galeotti Marco, Orioles Massimo, Saccà Elena, Byadgi Omkar, Pesaro Stefano, Di Cerbo Alessandro, Magi Gian Enrico
Department of Agricultural, Food, Environmental and Animal Sciences, DI4A, University of Udine, 33100 Udine, Italy.
International Program in Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, No. 1, Shuefu Road, Neipu, Pingtung 91201, Taiwan.
Animals (Basel). 2023 Mar 20;13(6):1103. doi: 10.3390/ani13061103.
Red mark syndrome (RMS) is a widespread skin disorder of rainbow trout in freshwater aquaculture, believed to be caused by a -like organism (MLO). Here, we aimed to study the pathologic mechanisms at the origin of RMS by analyzing field samples from a recent outbreak through gene expression, MLO PCR, quantitative PCR, and a histopathological scoring system proposed for RMS lesions. Statistical analyses included a One-Way Analysis of Variance (ANOVA) with a Dunnett's multiple comparisons test to assess differences among gene expression groups and a nonparametric Spearman correlation between various categories of skin lesions and PCR results. In short, the results confirmed the presence of a high quantity of 16S gene copy numbers of -like organisms in diseased skin tissues. However, the number of -like organisms detected was not correlated to the degree of severity of skin disease. -like organism DNA was found in the spleen and head kidney. The spleen showed pathologic changes mainly of hyperplastic type, reflecting its direct involvement during infection. The most severe skin lesions were characterized by a high level of inflammatory cytokines sustaining and modulating the severe inflammatory process. IL-1 β, IL-6, IL-10, MHC-II, and TCR were upregulated in severe skin lesions, while IL-10 was highly expressed in moderate to severe ones. In the moderate form, the response was driven to produce immunoglobulins, which appeared crucial in controlling the skin disease's severity. Altogether our results illustrated a complex immune interaction between the host and -like organism.
红斑综合征（RMS）是淡水养殖虹鳟鱼中一种广泛存在的皮肤疾病，据信是由一种类似支原体的生物体（MLO）引起的。在此，我们旨在通过对近期一次疫情爆发的现场样本进行基因表达分析、MLO聚合酶链反应（PCR）、定量PCR以及针对RMS病变提出的组织病理学评分系统，来研究RMS发病的病理机制。统计分析包括采用Dunnett多重比较检验的单因素方差分析（ANOVA），以评估基因表达组之间的差异，以及各类皮肤病变与PCR结果之间的非参数Spearman相关性分析。简而言之，结果证实患病皮肤组织中存在大量类似支原体生物体的16S基因拷贝数。然而，检测到的类似支原体生物体数量与皮肤疾病的严重程度无关。在脾脏和头肾中发现了类似支原体生物体的DNA。脾脏主要表现为增生型病理变化，反映出其在感染过程中的直接参与。最严重的皮肤病变特征是高水平的炎性细胞因子维持和调节严重的炎症过程。白细胞介素-1β（IL-1β）、白细胞介素-6（IL-6）、白细胞介素-10（IL-10）、主要组织相容性复合体II类分子（MHC-II）和T细胞受体（TCR）在严重皮肤病变中上调，而IL-10在中度至重度病变中高表达。在中度病变形式中，反应促使产生免疫球蛋白，这在控制皮肤疾病的严重程度方面似乎至关重要。总之，我们的结果说明了宿主与类似支原体生物体之间复杂的免疫相互作用。
