295 ASSESSMENT OF CYTOTOXICITY AND INTERFERENCE OF ATELEIA GLAZIOVIANA IN BOVINE HERPESVIRUS TYPE 1 (BoHV-1) INTERACTION WITH IN VITRO-MATURED BOVINE OOCYTES

Abstract

In vitro embryo production (IVP), as well as having a biotechnical importance, is a valuable tool for studies of gamete and/or embryo interaction with pathogens and xenobiotics. In consequence, it has become an excellent model not only for investigations about sanitary aspects, but also for aspects related to toxic processes. The aim of this study was to evaluate the effect of cytotoxic aqueous extract of Ateleia glazioviana and its interference on the interaction of bovine herpesvirus type 1 (BoHV-1) with bovine oocytes during the In vitro maturation (IVM) period. The statistical analysis of the experiments was made according to Student’s t-test (P < 0.05). The parameters used for this experiment were based on the morphological, physiological, and clastogenic action analysis of the bovine oocytes. The oocytes were collected from ovaries from slaughterhouse and divided into control group (G1, n = 214), a group infected with BoHV-1 (Los Angeles sample 105.5 TCID50 mL^-1(G2, n = 210), a group exposed to the extract of A. glazioviana, 0.24 g mL^-1; G3, n = 228), and a group simultaneously exposed to the virus and to the extract (G4, n = 210). For IVM, the oocytes were kept in TCM-199 supplemented with hormones and incubated at 38°C, 5%CO₂, and 95% humidity for 24 h. The oocytes in G1 showed high expansion of the cumulus cells and ooplasm uniform in appearance; oocytes in G2 showed uniform but moderate expansion of cumulus cells and retraction of ooplasm; the G3 group showed low and irregular expansion with degeneration of cumulus cells and retraction of ooplasm with a granular aspect; and oocytes in G4 showed degeneration of cumulus cells, retracted and granular ooplasm. We observed maturation rates of 81.3% in G1, 31.0% in G2, 5.7% in G3, and 1.4% in G4. As for the clastogenic action analysis, an additional group of oocytes, named in natura (n = 210), was evaluated and presented 41.9% of comets class 0 (zero), 34.8% class I, 12.4% class II, 7.1% class III, and 3.8% class IV G1 (n = 211) presented 6.1% of comets class 0, 47.8% class I, 31.3% class II, 11.0% class III, and 3.8% class IV Oocytes belonging to G3 (217) presented 0.5% of comets class 0, 19.8% class I, 28.1% class II, 34.1% class III, and 17.5% class IV G2 (n = 229) presented 4.4% of comets class 0, 61.2% class I, 26.6% class II, 4.8% class III, and 3.0% class IV Oocytes in G4 (n = 206) presented 3.9% of comets class 0, 26.2% class I, and similar amounts of comets level II (23.8%), III (22.8%), and IV (23.3%). The statistical analysis presented a significant difference in the final results. Such results show the cytotoxic effect of A. glazioviana in bovine oocytes. The simultaneous exposure to the virus and the extract aggravated the effect of the virus, suggesting an increase of the pathogen within the gametic cell.

Vitrocel/Embriolife.