Entamoeba histolytica: Apoptosis induced in vitro by nitric oxide species

• Published in: Experimental parasitology Vol. 116; no. 3; pp. 257 - 265
• Main Authors: Ramos, Espiridión, Olivos-García, Alfonso, Nequiz, Mario, Saavedra, Emma, Tello, Eusebio, Saralegui, Andrés, Montfort, Irmgard, Pérez Tamayo, Ruy
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.07.2007; Elsevier
• Subjects: Acute experimental amebic liver abscess; Animals; Apoptosis; Apoptosis - drug effects; Biological and medical sciences; Cricetinae; DNA Fragmentation; Entamoeba histolytica; Entamoeba histolytica - cytology; Entamoeba histolytica - drug effects; Entamoeba histolytica - physiology; Fundamental and applied biological sciences. Psychology; Hamster ( Mesocricetus auratus); In Situ Nick-End Labeling; Leishmania; Life cycle. Host-agent relationship. Pathogenesis; Liver Abscess, Amebic - parasitology; Male; Mesocricetus; Microscopy, Confocal; Nitrate; Nitrates - pharmacology; Nitric Oxide - pharmacology; Nitric Oxide Donors - pharmacology; Nitrite; Nitroprusside - pharmacology; Protozoa; Sodium Nitrite - pharmacology; Sodium nitroprusside; Trichomonas; Trypanosoma; Sodium nitroprusside; Nitrate; Entamoeba histolytica; Acute experimental amebic liver abscess; Nitrite; Hamster ( Mesocricetus auratus); Apoptosis; Protozoa; Lobosea; Nitric oxide; Parasite; In vitro
• ISSN: 0014-4894; 1090-2449
• DOI: 10.1016/j.exppara.2007.01.011

Apoptosis has been described in some parasites like Leishmania, Trypanosoma, and Trichomonas. This phenomenon has not been observed yet in Entamoeba histolytica. This work analyzed the in vitro effect of sodium nitroprusside, sodium nitrite and sodium nitrate (NOs) on E. histolytica apoptosis. Parasites incubated for 1 h with NOs revealed apoptosis 6 h later (95% viability), demonstrated by YOPRO-1, TUNEL, DNA fragmentation and low ATP levels. The caspase inhibitor Z-VAD-FMK inhibited total intracellular cysteine protease activity (CPA) but had no effect on apoptosis. When treated with NOs some amebic functions like complement resistance and hemolytic activity decreased but CPA and erythrophagocytosis remained unchanged. After treatment in vitro with NOs, parasite death was almost complete at 24 h; but when injected into hamster livers they disappeared in less than 6 h. These results show that apoptosis is induced in vitro by NOs in E. histolytica and renders them incapable of surviving in hamster’s livers.