Abstract:

Objective　To explore whether the Picria felterrae extractive (PFE) can alleviate the symptoms of mice with burn sepsis by regulating the FMS like tyrosine kinase 3 ligand (Flt3L) and its regulation effect on T cell function. Methods　The study was conducted from July 2022 to April 2023 at the animal experimental center of Ankang Traditional Chinese Medicine Hospital. According to the random number table method, 72 SPF male C57 mice [body mass 21 - 25 (22±2) g, 10 weeks old] were randomly divided into 6 groups: a burn group, a model group, low, middle, and high dose of PFE groups, and a positive group. The low, middle, and high dose of PFE groups were given 0.5 g/kg, 1.0 g/kg, and 2.0 g/kg of PFE on the next day after model preparation for 1 week. In the positive group, 10 μg of Flt3L was injected subcutaneously on the next day after model preparation for 9 days. The fluorescence intensity of the back skin was detected on day 1, 3, and 5 after administration; the levels of serum interleukin (IL)-6, IL-1β, tumor necrosis factor α (TNF-α), proliferation activity of peripheral blood T lymphocytes, changes of spleen T-lymphocyte subsets, histopathological changes of subcutaneous tissue, lung, and spleen, and expression levels of IL-2, IL-4, interferon-γ (IFN-γ), and Flt3L protein were detected. Univariate analysis of variance and SNK-q test were used for statistical analysis. Results　Compared with the burn group, the fluorescence intensity of the wound bacteria in the model group was enhanced, and the levels of IL-6 [(59.44±5.41) μg/L vs. (23.47±3.29) μg/L], IL-1β [(80.47±6.83) μg/L vs. (32.74±4.36) μg/L], and TNF-α [(12.33±1.15) μg/L vs. (4.76±0.97) μg/L], pathology scores of wound tissue, lung tissue, and spleen tissue, IL-2, IL-4, and IFN-γ protein expressions, and CD8⁺T cell proportion [(65.33±5.68)% vs. (26.72±6.75)%] in the model group were all higher, but the T lymphocyte proliferation activity, CD3⁺T cell proportion [(34.55±3.29)% vs. (64.49±9.33)%], CD4⁺T cell proportion [(16.71±3.49)% vs. (48.18±7.36)%], and CD4⁺/CD8⁺ [(0.26±0.06) vs. (1.81±0.35)] were all lower (all P<0.05). Compared with the model group, the fluorescence intensities of the wound bacteria in the low, middle, and high dose of PFE groups and the positive group were weakened, and the levels of IL-6, IL-1β, and TNF-α, pathology scores of wound tissue, lung tissue, and spleen tissue, IL-2, IFN-γ, and IL-4 protein expressions, and CD8⁺T cell proportion were all lower, but the T lymphocyte proliferation activity, CD3⁺T, CD4⁺T, and CD4⁺/CD8⁺ were all higher, in dose-dependent manners (all P<0.05). Conclusion　PFE can reduce the bacterial content of infected wound, inflammation, and organ damage, and the mechanism may be related to up-regulation of Flt3L, promotion of T lymphocyte activity, and remission of immunosuppression.

Key words:

Sepsis, Burn, Picria felterrae extractive, FMS like tyrosine kinase 3 ligand, Animal experiment

摘要：

目的　探讨苦玄参提取物（PFE）通过调节酪氨酸激酶-3配体（Flt3L）对烧伤脓毒症模型小鼠T细胞功能的调控作用。方法　研究于2022年7月至2023年4月在安康市中医医院动物实验中心进行。按照随机数字表法将72只SPF雄性C57小鼠［体质量为21～25（22±2）g，10周龄］分为6组，烧伤组、模型组和PFE低、中、高剂量组及阳性组。PFE低、中、高剂量组模型制备结束后次日分别灌胃0.5 g/kg、1.0 g/kg、2.0 g/kg PFE，连续给药1周；阳性组：模型制备结束后次日，皮下注射10 μg Flt3L，连续注射9 d。给药结束后1、3、5 d分别检测背部皮肤荧光强度；给药后检测血清白细胞介素（IL）-6、IL-1β、肿瘤坏死因子α（TNF-α）水平、外周血T淋巴细胞增殖活性、脾脏T淋巴亚群变化、皮下、肺、脾脏组织病理学变化及IL-2、IL-4、干扰素-γ（IFN-γ）、Flt3L蛋白表达水平。统计学方法采用单因素方差分析和SNK-q检验。结果　模型组创面细菌荧光强度、IL-6［（59.44±5.41）μg/L比（23.47±3.29）μg/L］、IL-1β［（80.47±6.83）μg/L比（32.74±4.36）μg/L］、TNF-α［（12.33±1.15）μg/L比（4.76±0.97）μg/L］水平、创面组织、肺组织、脾组织病理评分、IL-2、IL-4、IFN-γ蛋白表达、CD8⁺T细胞比例［（65.33±5.68）%比（26.72±6.75）%］均高于烧伤组，T淋巴细胞增殖活性、CD3⁺T细胞比例［（34.55±3.29）%比（64.49±9.33）%］、CD4⁺T细胞比例［（16.71±3.49）%比（48.18±7.36）%］、CD4⁺/CD8⁺［（0.26±0.06）比（1.81±0.35）］均低于烧伤组（均P<0.05）。与模型组相比，PFE低、中、高剂量组、阳性组创面细菌荧光强度较弱；IL-6、IL-1β、TNF-α水平、创面组织、肺组织、脾组织病理评分、IL-2、IL-4、IFN-γ蛋白表达、CD8⁺T细胞比例均低于模型组，T淋巴细胞增殖活性、CD3⁺T、CD4⁺T、CD4⁺/CD8⁺均高于模型组，具有剂量依赖性（均P<0.05）。结论　PFE可降低感染创面细菌含量，降低炎症反应以及器官损伤，其机制可能与上调Flt3L、促进T淋巴细胞活性缓解免疫抑制有关。

关键词:

脓毒症, 烧伤, 苦玄参提取物, 酪氨酸激酶-3配体, 动物实验