Voluntarily ingestion of a sedative prior to euthanasia with CO2 in mice

Our objective was to study if the voluntary ingestion of a sedative (tiletamine-zolazepam; Zoletil®) prior to euthanasia with CO2 reduces the aversiveness to this gas in female and male C57BL/6 mice.
A total of 80 C57BL/6 mice (40 females, 40 males) were used in the study. Animals were housed in pairs of the same sex. The treatments differed in the dose of the sedative (tiletamine-zolazepam): Control (0 mg/kg), Z10 (10 mg/kg), Z20 (20 mg/kg), Z40 (40 mg/kg), Z80 (80 mg/kg), and Z100 (100 mg/kg).

The data file contains two tabs. In both tabs, Columns A to E include:
Cage_number: there were 40 cages in total.
Sex: half of the cages were females and half males.
MouseID: there were two mice/cage and to differentiate between them one was marked.
Dosing Period: (1-5) A total of 5 dose escalation sessions were performed. At each dosage session, each treatment cage was randomly paired with a control cage containing mice of the same sex, resulting in a total of 16 mice from four male cages and four female cages per session.
Type_of_treatment: Control, Z10, Z20, Z40, Z80 and Z100.

1) Pre-euthanasia Data Tab. Includes the behavioural data reported during 1200 s of observation after the voluntarily ingestion of the sedative and prior to euthanasia with CO2 (sedation period). Due to video loss for some mice, we standardised the behavioural reporting to the first 800 s of the sedation period. Under the column "Event_frequency" (Column K) are those behaviours coded as frequency (e.g., rearing and jumping), and under the column "Behaviour_duration" (Column L) are those behaviours coded as duration (e.g., walking on lid, ataxia). "CC In" and "CC Out" (Column I) indicates when the cream cheese +/- sedative was introduced and removed from the cage. "CC Out - End Obs" (Column J) is the total observation time. The duration for the behaviours or conditions appears under the column "Duration_Time" (00:00:00). The columns "Onset_Time" (Column F) and "Offset Time" (Column G) indicate the time when the behaviour or condition started and ended, respectively.

2) Euthanasia Data Tab. Includes the data about the voluntary intake of the cream cheese +/- sedative (Columns N to V); "z_dose" (Column U) is the planned tiletamine-zolazepam dose and "actual_z_dose" (Column V) is the real dose ingested. The behaviours recorded during the euthanasia with CO2 are also included (Columns F to K). Rearing (Column F) and jumping (Column G) were coded as frequency. The other behaviours were coded as durations (seconds). Under "Corrected_Latency_to_Ataxia" (Column H) appears the latency to ataxia from the onset of CO2 (seconds). The other latencies were coded from the previous behaviour as follows: "Latency to recumbency from ataxia" (Column I) "Latency to laboured breathing from recumbency" (Column J), and "Latency to last breath from laboured breathing" (Column K). The duration for which the CO2 was on is included in Column L.

本研究旨在探究：在使用二氧化碳（CO₂）实施安乐死（euthanasia）前，自愿摄入镇静剂（sedative）替来他明-唑拉西泮（tiletamine-zolazepam；Zoletil®）是否会降低雌雄C57BL/6小鼠对该气体的厌恶性。

本研究共纳入80只C57BL/6小鼠，其中雌性、雄性各40只。实验动物按性别成对饲养。

实验设置了不同剂量的替来他明-唑拉西泮给药组别：对照组（0 mg/kg）、Z10（10 mg/kg）、Z20（20 mg/kg）、Z40（40 mg/kg）、Z80（80 mg/kg）及Z100（100 mg/kg）。

本数据集包含两个工作表（tabs），两个工作表的A至E列均包含以下字段：
1. 笼号（Cage_number）：本研究共设置40个饲养笼。
2. 性别（Sex）：雌性饲养笼与雄性饲养笼各占一半。
3. 小鼠编号（MouseID）：每个饲养笼饲养2只小鼠，通过标记区分个体。
4. 给药周期（Dosing Period）：取值范围为1至5，本研究共开展5次剂量递增给药实验。每次给药实验中，各给药组饲养笼均与同性别对照组饲养笼随机配对，每次实验共纳入4个雄性饲养笼与4个雌性饲养笼，合计16只小鼠。
5. 处理类型（Type_of_treatment）：包括Control、Z10、Z20、Z40、Z80及Z100。

1) 安乐死前行为数据工作表（Pre-euthanasia Data Tab）
该工作表包含镇静剂自愿摄入后、CO₂安乐死前的1200秒观察期内的行为学数据（即镇静期）。由于部分小鼠的视频记录丢失，我们将行为记录标准化为镇静期的前800秒。其中，列K“事件发生频率（Event_frequency）”对应的行为为频率编码行为（如直立、跳跃）；列L“行为持续时长（Behaviour_duration）”对应的行为为时长编码行为（如笼盖行走、共济失调）。列I“CC In”与“CC Out”分别表示添加/未添加镇静剂的奶油膏放入笼内和取出笼内的时间；列J“CC Out - End Obs”为总观察时长。行为或状态的持续时长记录于“持续时长（Duration_Time）”列，格式为00:00:00。列F“起始时间（Onset_Time）”与列G“结束时间（Offset Time）”分别表示行为或状态的开始与结束时刻。

2) 安乐死数据工作表（Euthanasia Data Tab）
该工作表包含添加/未添加镇静剂的奶油膏自愿摄入相关数据（列N至V）：列U“计划给药剂量（z_dose）”为预设的替来他明-唑拉西泮给药剂量，列V“实际摄入剂量（actual_z_dose）”为小鼠实际摄入的剂量。同时包含CO₂安乐死过程中记录的行为学数据（列F至K）：其中直立（列F）与跳跃（列G）采用频率编码，其余行为采用时长编码，单位为秒。列H“共济失调校正潜伏期（Corrected_Latency_to_Ataxia）”记录了自CO₂暴露开始至出现共济失调的潜伏期，单位为秒。其余潜伏期均基于前序行为进行标注：列I“从共济失调至卧倒的潜伏期”、列J“从卧倒至呼吸困难的潜伏期”以及列K“从呼吸困难至最后一次呼吸的潜伏期”。列L记录了CO₂通气的持续时长。