Comparing the Effect of Methods of Rat Euthanasia on the Brain of Wistar Rats: Cervical Dislocation, Chloroform Inhalation, Diethyl Ether Inhalation and Formalin Inhalation

Abstract

Contentions still exist as to the most humane method of sacrificing experimental animals. Beyond humaneness, there is also the issue of appropriateness of a method of sacrifice with regards to organ safety. This study compared four common methods of rodent sacrifice used in Nigeria and their effects on the brain. Twenty male Wistar rats weighing 150 to 180g were randomly separated into four groups of five rats each. After a two week period of acclimatization, the animals were sacrificed; Group A by Cervical dislocation (CD) which also served as control, Group B by chloroform inhalation (CI), Group C by diethyl ether inhalation (DEI) and group D by Formalin inhalation (FI). The time taken for the animals to pass out was documented and the brains were harvested. Four of the brains from rats in each group were homogenized in phosphate buffer solution and centrifuged at 10000rpm. The supernatant were used for antioxidant studies. The remaining one brain from each group were fixed in 10% formal saline and after 48 hours, the cerebellum (CB) and hippocampus (Hp) were used for histological studies using the H & E method. Our results show although CD was the quickest, it gave the least quantity of blood. Meanwhile CI was the most humane, gave the most blood and saved time compared to DEI and FI. None of the methods of sacrifice showed adverse effect on the antioxidant parameters of the rats. However, histological studies showed that while CD and CI showed no adverse effects on the hippocampus, only CD was completely safe for the CB. The other methods showed various levels of cell death. It is therefore expedient to consider these factors in making the choice of an appropriate method of sacrifice and to use the most humane and safest method with reference to the organ studied.

Black solo garlic protects hepatic and renal cell function in streptozotocin-induced rats

“…The variables measured were urea, creatinine, β 2 -microglobulin, total protein, albumin, and glutathione S-transferase (GST). Rats were euthanized and decapitated by being put into a large bottle containing ether ( 16 ).…”

Pro-inflammatory effects of placebo neurosurgery in rats: age-related features

“…In order to allow for liquid diffusion into the brain tissue and to prevent reflux, the injector was left in place for 5 minutes before slowly withdrawing. Placebo surgery in group 3 was conducted according to the protocol developed for modeling unilateral AD, induced by the intrahippocampal infusion of human amyloid beta 1 -40 [1,15]. Animals from group 4 were scalped from the point of intersection of the sagittal suture with the bregma (zero point) at 2 mm distally, 2 mm laterally, and 3.5 mm deep, and a burr hole was made with an injection needle directly into the hippocampus.…”

“…The pro-inflammatory effects of placebo surgery were estimated at day 29 after the manipulation. Cervical dislocation was used to sacrifice the animals because it minimizes cell death in brain structures and allows for a high viability rate in microglia cells after the isolation [1]. Peripheral blood and brain tissue specimens were sampled immediately after the rat's euthanasia.…”

Bioanalytical RP-HPLC method validation for resveratrol and its application to pharmacokinetic and drug distribution studies

“…The rats were anesthetized using diethyl ether (~4-5 ml via inhalation route) (Aguwa et al, 2020;Plate et al, 2005) and sacrificed humanely, followed by dissecting the animals to collect different organs such as liver, kidney, spleen, breast tissue, lung, and heart. The isolated organs were weighed and then homogenized in 0.9% NaCl containing ascorbic acid (Juan et al, 2010a).…”

“…The information available on the pharmacokinetic and tissue distribution of RVT is limited, despite the numerous literature studies on its potential efficacy. Bertelli et al (1996) were able to quantify RVT in the plasma and tissues after the administration of red wine to the rats. Emilia et al (2010) developed a liquid chromatographymass spectrometry (LC-MS) method to quantify RVT along with its metabolites in the plasma and different tissues after the intravenous administration of RVT in rats (Juan et al, 2010b).…”