Plasma glutathione peroxidase (GPx 3) activity in the freshwater turtle trachemys scripta elegans after isoflurane inhalation anesthesia

Abstract

Introduction. Glutathione peroxidases are selenoenzymes which have a crucial role in the protection of animals against oxidative stress. Materials and Methods. From September 2017 to April 2018, a group of eight red-eared sliders were admitted at the Clinic for Small Animals, Faculty of Veterinary Medicine, University of Belgrade for elective diagnostic celioscopy. The turtles were of unknown age, weight from 1.20 kg to 1.86 kg. The anesthesia protocol involved using ketamine and medetomidine, both at a low dosage (10 mg kg-1 and 0.1 mg kg-1, respectively) as induction, after which anesthesia was maintained using isoflurane at 3% (vapor setting) in 100% oxygen (0.5 L min-1). Medetomidine was reversed with atipamezole (0.2 mg kg-1), given intramuscularly. The elective celioscopy was performed according to standard protocols. One day prior to anesthesia, heparinized blood samples were taken using the subcarapacial venous plexus for venipuncture. The second sampling took place three hours after the anesthetics were administered. Results and Conclusions. GPx3 activity in the blood plasmas (n=8) was measured by the coupled test as described by Günzler et al. (1974). Data were tested for normality by the Shapiro-Wilk normality test and the groups were compared using a paired t-test. Blood plasma GPx3 activity was significantly higher (p=0.009) after a three-hour recovery period from inhalation anesthesia performed for elective diagnostic celioscopy, than before anesthesia. The measured post-anesthesia GPx3 activities were, on average, 80% higher than the measurements prior to anesthesia. It can be concluded that the statistically significant increase in the activity of plasma GPx3 from 91.02±36.05 mKat L-1 prior to anesthesia to 160.21±58.94 mKat L-1 three hours after anesthesia is due to the change in oxygen saturation. This is increased to 100% during the procedure, thus exposing the turtles to conditions of high oxygen saturation.

Uvod. Glutation peroksidaze su selenoenzimi koji igraju ključnu ulogu u zaštiti životinja od oksidativnog stresa. Materijal i metode. Od septembra 2017. do aprila 2018. godine, grupa od osam crvenouhih kornjača je primljena na Kliniku za male životinje, Fakulteta Veterinarske Medicine, Univerziteta u Beogradu zbog izvođenja elektivne dijagnostičke celioskopije. Kornjače su bile nepoznate starosti, mase između 1,20 kg i 1,86 kg. Anastetički protokol je uključivao primenu ketamina (10 mg kg-1) i medetomidina (0.1 mg kg-1) za indukciju, oba u niskim dozama, nakon čega je anestezija održavana primenom izoflurana u koncentraciji od 3% (podešen na isparavanje) u 100% kiseoniku (0.5 L min-1). Dejstvo medetomidina je neutralizovano atipamezolom (0.2 mg kg-1), aplikovanim intramuskularno. Elektivna celioskopija je izvedena u skladu sa standardnim protokolima. Heparinizovani uzorci krvi su uzeti jedan dan pre uvođenja u anesteziju venepunkcijom iz subkarapacijalnog venskog pleksusa. Drugo uzorkovanje krvi je uzvršeno tri sata nakon administracije anestetika. Rezultati i zaključak. GPx3 aktivnost u krvnoj plazmi (n=8) je izmerena primenom kuplovane reakcije, kao što su opisali Günzler i sar. (1974). Normalna distribucija podataka je testirana pomoću Shapiro - Wilk testa normalnosti (p>0,05), a grupe su poređene koristeći t test za zavisne uzorke. Aktivnost GPx3 u krvnoj plazmi je bila značajno viša (p=0.009) u uzorcima uzetim nakon trosatnog perioda oporavka od inhalacione anestezije aplikovane radi izvođenja elektivne celioskopije, nego u uzorcima uzetim pre aplikovanja anestezije. Vrednosti GPx3 izmerene nakon anestezije bile su u proseku 80% više od vrednosti pre anestezije. Može se zaključiti da je statistički značajan porast u aktivnosti GPx3 u plazmi od 91.02±36.05 mKat L-1, pre anestezije do 160.21±58.94 mKat L-1, tri sata nakon anestezije uzrokovan promenom u saturaciji kiseonika. Tokom intervencije saturacija kiseonika se povećava i do 100% čime se kornjače uvode u uslove visoke saturacije kiseonikom.