Morphological changes depending on the content of clozapine and its metabolites in the lungs and serum (Experimental study)

Materials and methods. The experiments were performed on male outbred rats weighing 290-350 g at the age of 20 weeks (n=15). The animals were divided into 3 groups: Group 1 — reference group (intact rats) (n=5); Group 2-poisoning with clozapine (n=5); Group 3 — poisoning with a combination of clozapine with ethanol (n=5). Clozapine was administered orally at a dose of 150 mg per kg of animal's body weight under general anesthesia; alcohol was administered together with clozapine orally at a dose of 5 ml per kg of animal's body weight. Further study was carried out 24 hours after administration of drugs to animals of the 2nd and 3rd groups. After euthanasia of the animals by decapitation, tissue samples of lungs were embedded in paraffin according to the standard technique. Then 5-μm thick histological sections were made and examined using light microscopy with the aid of a Nikon Eclipse E-400 microscope equipped with a video system based on the Watec 221S camera (Japan) at magnification of X200 and X400. The following pathological patterns were assessed: disorder of blood circulation (hyperemia, hemorrhage, and sludge), the presence of atelectasis and dystelectasis, the presence of emphysema, the cellular response (an increase in the white blood cell count), and desquamation of epithelium into the lumen of the bronchi. A chemical and toxicological study was performed on a high-performance liquid chromatograph with mass detector Agilent Technologies 430 Triple Quad LC/MS (Germany). To obtain chromatograms, the following software was used: Agilent Mass Hunter Workstation for series tripple Quadrapole vers. B06.00 build 6.0.6.25.4sp4. The following software was used for processing chromatograms: Agilent Mass Hunter Quantitive Analysis vers. B 07.00 build 7.0.457.0. Serum and lung homogenate levels of clozapine, norclozapine, and clozapine-N — oxide were evaluated. Results. In 24 hours, animals in the 2nd group exhibited atelectasis and dystelectasis in the lung tissue, and leukocyte infiltration; in the 3rd group, arterial hyperemia, cellular response (an increase in the white blood cell count), atelectasis and dystelectasis, and thickening of interalveolar septa were revealed. In 24 hours, in the lungs of animals of the 3rd group, the concentration of clozapine increased by 22.2-fold, norclozapine by 6.6-fold, and clozapine-N-oxide by 6.2-fold as compared to the 2nd group; in serum it increased by 5.7-, 2.0-and 4.6-fold, respectively. Conclusion. In the case of poisoning with clozapine in combination with ethanol, a complex of pathological changes in the lungs develops, which is more severe than the isolated effect of clozapine administered as a single drug. The concentration of clozapine and its metabolites in the lung tissue and blood serum is higher when it enters the body in combination with ethanol. © 2018, V.A. Negovsky Research Institute of General Reanimatology. All rights reserved.