Levels of glutathione peroxidase, lipoperoxidase and some biochemical and haematological parameters in gazelles anaesthetised with a tiletamin–zolazepam–xylazine combination

Comparative Study of the Aftereffect of CO2 Inhalation or Tiletamine–Zolazepam–Xylazine Anesthesia on Laboratory Outbred Rats and Mice

CO2 inhalation is currently the most common method of euthanasia for laboratory rats and mice, and it is often used for further terminal blood sampling for clinical biochemical assays. Lately, this method has been criticized due to animal welfare issues associated with some processes that develop after CO2 inhalation. The stress reaction and the value of the clinical laboratory parameters significantly depend on the used anesthetics, method, and the site of blood sampling. Especially in small rodents, an acute terminal state followed by a cascade of metabolic reactions that can affect the studied biochemical profile may develop and cause unnecessary suffering of animals. The aim of this study was to compare the stability of biochemical parameters of outbred Sprague Dawley rats and CD-1 mice serum collected after CO2 inhalation or the intramuscular injection of tiletamine–zolazepam–xylazine (TZX). The serum content of total protein and albumin, cholesterol, triglycerides, aspartate aminotransferase (AST), alanine aminotr ansferase (ALT), alkaline phosphatase (ALP), total bilirubin, and creatinine was decreased by the injection of TZX in comparison with CO2 inhalation. In addition, the levels of calcium, phosphates, chlorides and potassium were lowered by TZX vs. CO2 administration, while the level of sodium increased. Finally, the level of the majority of serum clinical biochemical parameters in rats and mice tend to be overestimated after CO2 inhalation, which may lead to masking the possible effect of anti-inflammatory drugs in animal tests. Injection anesthesia for small rodents with TZX is a more feasible method for terminal blood sampling, which also reduces the suffering of animals.

Using Tiletamine-Zolazepam-Xylazine Anesthesia Compared to CO2-inhalation for Terminal Clinical Chemistry, Hematology, and Coagulation Analysis in Mice

INTRODUCTION

It is important that the method of anesthesia of mice does not considerably alter the animal's physiological and metabolic status before terminal blood sampling taken in order to analyze clinical pathology parameters.

METHODS

Hematology, hemostasis, and clinical chemistry parameters were compared in male and female BALB/c mice exposed to either tiletamine-zolazepam-xylazine (TZX) anesthesia or euthanasia in carbon dioxide (CO₂₎ chamber to reveal an alternative method of anesthesia vs. the recommended CO₂ inhalation. Blood samples were taken from the inferior vena cava.

RESULTS

Clinical blood parameters in mice exposed to CO₂ inhalation or TZX anesthesia proved to be substantially different. The TZX group had lower activated partial thromboplastin time (APTT) and fibrinogen (statistically in males and tending in females) and lower platelets (PLT), red blood cells (RBC), hemoglobin (HGB), and white blood cells (WBC) in both sexes. TZX anesthesia resulted in lower blood serum concentrations of total protein, albumin and globulins, creatinine in males (higher in females); cholesterol, triglycerides, alanine aminotransferase (АLT) and alkaline phosphatase (AP) in both sexes, and bilirubin in males. The calcium level decreased in TZX-anesthetized males and females while the phosphates decreased only in females. The volume of serum obtained from females of TZX group was approximately two times higher than in the CO₂-anesthetized group, with the degree of hemolysis tending to decrease.

DISCUSSION

The studied method of mouse anesthesia, followed by terminal blood sampling and analysis of clinical pathology parameters, suggests that TZX is a good alternative to CO₂ inhalation in toxicological and other nonclinical studies. The differences in hemostasis, hematology, and clinical chemistry parameters between these groups are supposedly associated with alterations in physiological and metabolic status of mice under conditions of increasing hypoxia, respiratory standstill, and circulatory arrest after CO₂ inhalation.

Effects of the tiletamine/zolazepam-xylazine-tramadol combination on plasma oxidative status and haematological indicators in miniature pigs

Oxidative stress in the body occurs when the production of free radicals overwhelms the antioxidant defence systems. The aim of this study was to examine the effects of a tiletamine/zolazepam-xylazine-tramadol combination on the antioxidant status, lipoperoxidase and blood cell indicators in eight miniature pigs. Baseline measures were recorded prior to anaesthesia, then the animals were anaesthetized with the combination of tiletamine/zolazepam (3.5 mg/kg), xylazine (1.32 mg/kg), and tramadol (1.8 mg/kg). Blood samples were collected from the anterior vena cava at 15, 30, 60, 90, 120 min, 24 h, and 72 h after anaesthesia. Plasma malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase concentrations were measured by colorimetry, and red blood cell counts, white blood cell counts, haemoglobin and packed cell volume were determined using an automated cell counter. The results showed that the concentration of malondialdehyde increased significantly at 30 and 60 min after the injection (P< 0.05), whereas glutathione peroxidase and catalase activity increased slightly (P> 0.05) then returned to baseline values after 90 min (P> 0.05). Superoxide dismutase activity increased significantly (P< 0.05) at 30 and 60 min, and then gradually decreased to baseline values after 90 min. Changes in red blood cell counts, haemoglobin and packed cell volume were not significant, while white blood cell count decreased significantly (P< 0.05) at 30 and 60 min. Our study is the first to demonstrate that tiletamine/zolazepam-xylazine-tramadol provide antioxidant effects, which may be proposed for alleviating the stress of examination and research at veterinary clinics or long-distance transportation.

Different fasting periods in tiletamine-zolezepam-anethetized cats: Glycemia, recovery, blood-gas and cardiorrespiratory parameters

The effects of different fasting periods on glycemia levels and on cardiorrespiratory parameters in tiletamine-zolazepam-anesthetized cats were evaluated. Twenty one animals were randomly assigned to three groups: 8 hours (G8), 12 hours (G12) or 18 hours (G18) of the preoperative fasting. The tiletamine-zolazepam (2 mg/kg) was administered intravenously. The heart rate (HR), respiratory rate (fR), rectal temperature (T R), glycemia (G), laboratorial glycemia (Glab), venous oxygen partial pressure (PvO2), venous carbon dioxide partial pressure (PvCO2), venous hemoglobin saturation (SvO2), pH, base deficit (BD), bicarbonate concentration (HCO3- ) and haematocrit were evaluated at 90 minutes after the last meal (T0), immediately before anesthesia (T1) and at ten (T2) and thirty (T3) minutes after tiletamine-zolezepam administration. The time between the administration of anesthetic and the cat's trial to elevate head (Th) and the interval between drug administration and aniamal's quadrupedal position (Tqp) were recorded. No differences among groups were recorded for glycemia, HR, PvO2, SvO2, pH, BD, HCO3-, Ht and Tqp. In G12 from T2, glycemia increased and from T1 PvCO2 decreased. At T1, PvO2 increased in all groups. In G8 and G12, from T1, DB and HCO3- decreased. In G12 and G18, from T2, Ht decreased. In G12, the Th mean was higher than G8. In conclusion, in tiletamine-zolazepam-anesthetized cats, the different preoperative fasting did not influence glycemia, blood-gas and cardiorrespiratory parameters. Additionally, there was no relationship between glycemia and anesthesia recovery.