Porphyrinogenic agents and the haem protein nitric oxide synthase: changes in the localization of the isoform eNOS in the liver of mice

RUSPINI, SILVINA; MEISS, R; LAVANDERA, J; BATLLE, ALCIRA; BUZALEH, ANA MARIA

Cardiff

Congreso; PORPHYRINS & PORPHYRIAS; 2011

British Association of Dermatology

Hepatic porphyrias lead to liver damage. The existence of haem as a functional group in a large variety of housekeeping proteins is crucial for life and death. Under haem-deficiency conditions, cells fail to survive and subsequently die because of impairment of major vital functions carried out by haem proteins. Nitric oxide (NO) synthase (NOS) is the enzyme responsible for NO synthesis in mammalian tissues. Four NOS isoforms have been described: neuronal NOS (nNOS), endotelial NOS (eNOS), inducible NOS (iNOS) and mitocondrial NOS (mtNOS). The administration of volatile anaesthetics and other porphyrinogenic agents produces alterations in the activity and expression of NOS in the brain and liver of mice. We also previously observed changes in the localization of nNOS and mtNOS due to these agents in the liver of mice. The aim of this work was to investigate if porphyrinogenic agents also produce any alteration in the localization of the isoform eNOS. For this purpose livers from mice treated with volatile anaesthetics such as Enflurane and Isoflurane and allylisopropylacetamide (AIA) were removed and fixed in 10% neutralbuffered formalin. Samples of hepatic lobules were processed routinely and embedded in paraffin. At least six microtome sections of 3–5 lm were stained with haematoxylin and eosin. Immunohistochemistry was performed using the streptavidinbiotin- peroxidase complex system LSAB (Dako, Glostrup, Denmark). Acute anaesthetics administration produced an increase in the staining intensity and the number of cells positive for eNOS in the nuclei (50–75% vs. 10% in control group). In the cytoplasm the results were different depending on the anaesthetic studied, revealing a diminution of positive cells for Enflurane (<10% vs. 25–50% in control group), while an increase was observed for Isoflurane (25–50% vs. 25% in control group). When these anaesthetics were administered chronically no variation were detected in the staining intensity of the expression but the number of cells positive for eNOS increased in both cytoplasm (25–75% vs. 25% in control group) and nuclei (25–50% vs. 10% in control group). In the group receiving AIA, increases in intensity of expression and in number of positive cells were also detected in both the cytoplasm and the nuclei. These effects were not observed in sinusoidal macrophages (von Kupffer cells) as a result of the action of the xenobiotics studied. Liver NOS alterations reported previously and here could affect the metabolic functions of this organ and probably produce severe systemic damage at the vascular level due to the deregulation of NO synthesis.