Universidade Federal do Ceará, Departamento de Bioquímica e Biologia Molecular, Fortaleza, CE, Brasil.
Universidade Federal Rural de Pernambuco, Departamento de Biologia, Recife, PE, Brasil.
Mem Inst Oswaldo Cruz. 2020 Nov 23;115:e200458. doi: 10.1590/0074-02760200458. eCollection 2020.
Calotropis procera latex protein fraction (LP) was previously shown to protect animals from septic shock. Further investigations showed that LP modulate nitric oxide and cytokines levels.
To evaluate whether the protective effects of LP, against lethal bacterial infection, is observed in its subfractions (LPPII and LPPIII).
Subfractions (5 and 10 mg/kg) were tested by i.p. administration, 24 h before challenging with lethal injection (i.p.) of Salmonella Typhimurium. LPPIII (5 mg/kg) which showed higher survival rate was assayed to evaluate bacterial clearance, histopathology, leukocyte recruitment, plasma coagulation time, cytokines and NO levels.
LPPIII protected 70% of animals of death. The animals given LPPIII exhibited reduced bacterial load in blood and peritoneal fluid after 24 h compared to the control. LPPIII promoted macrophage infiltration in spleen and liver. LPPIII restored the coagulation time of infected animals, increased IL-10 and reduced NO in blood.
LPPIII recruited macrophages to the target organs of bacterial infection. This addressed inflammatory stimulus seems to reduce bacterial colonisation in spleen and liver, down regulate bacterial spread and contribute to avoid septic shock.
先前的研究表明，牛奶菜乳胶蛋白部分（LP）可保护动物免受脓毒性休克的影响。进一步的研究表明，LP 可调节一氧化氮和细胞因子的水平。
评估 LP 的亚组分（LPPII 和 LPPIII）是否具有对抗致死性细菌感染的保护作用。
通过腹腔注射，在 challenged 用致死剂量的鼠伤寒沙门氏菌（i.p.）攻击之前 24 小时，测试亚组分（5 和 10 mg/kg）。显示出更高存活率的 LPPIII（5 mg/kg）被用于评估细菌清除率、组织病理学、白细胞募集、血浆凝固时间、细胞因子和 NO 水平。
LPPIII 保护了 70%的动物免受死亡。与对照组相比，给予 LPPIII 的动物在 24 小时后血液和腹腔液中的细菌负荷减少。LPPIII 促进了巨噬细胞在脾和肝中的浸润。LPPIII 恢复了感染动物的凝血时间，增加了血液中的 IL-10 并降低了 NO。
LPPIII 将巨噬细胞募集到细菌感染的靶器官。这种针对炎症刺激的方法似乎减少了脾和肝中的细菌定植，下调了细菌的传播，并有助于避免脓毒性休克。
