Animal Research Report: [Short title of the study]

Report template for in vivo research using animals. The sections cover the topics of the ARRIVE 2.0 guidelines, both the Essential 10 and the Recommended Set, arranged in manuscript order and written in original words for this collection. Use it with the official ARRIVE checklist and explanation document from arriveguidelines.org and with your institution's animal welfare requirements. This is a reporting format, not veterinary, ethical or statistical advice. Replace every [bracketed] value and every row marked Example.

Document control

Approvals

Revision history

Contents

1. Title and abstract
2. Introduction
3. Methods
4. Results
5. Discussion
6. Other information
7. Appendices

1. Title and abstract

The title names the species and the main intervention; the abstract summarises objectives, species, methods, results and conclusions.

Title: [Effect of [intervention] on [outcome] in [species and strain, sex] model of [condition]]

2. Introduction

The introduction justifies the research and the use of animals.

2.1 Background (ARRIVE 12)

[Summarise the scientific background and the gap. Explain why animals were needed, why this species and model were chosen and how the model relates to the human or animal condition of interest.]

2.2 Objectives (ARRIVE 13)

3. Methods

This section describes the ethical framework, design and procedures.

3.1 Ethical statement (ARRIVE 14)

[Name the ethical review body, the approval or licence number and the legislation or guidelines followed. If no approval was required, explain why.]

3.2 Study design (ARRIVE 1)

The design is summarised below.

3.3 Sample size (ARRIVE 2)

For a two-group comparison of means, the number per group is:

Example: Expected difference $\Delta = 20\ \text{mm}^3$, standard deviation $\sigma = 15\ \text{mm}^3$ from pilot data, two-sided $\alpha = 0.05$ and 80% power give $n = 2 \times 225 \times (1.96 + 0.84)^{2} / 400 \approx 8.8$, rounded up to 9; 12 per group were used to allow for an expected 20% surgical mortality.

When a power calculation is not possible, for example in exploratory work, the resource equation gives an upper bound:

where $N$ is the total number of experimental units and $T$ the number of treatment groups.

3.4 Inclusion and exclusion criteria (ARRIVE 3)

3.5 Randomisation (ARRIVE 4)

[Say whether randomisation was used to allocate units to groups, the method used to generate the sequence (for example a computer random number generator, blocked by cage or batch), and how confounders such as order of treatment and measurement or cage location were controlled.]

Example: Animals were allocated to the four groups in blocks of four using a sequence generated in R (set.seed(20250314), sample()) by a colleague not involved in surgery. Each block was one surgery day, so every group was represented on every day. Cage positions on the rack and the order of outcome assessment followed the same random sequence.

3.6 Blinding (ARRIVE 5)

3.7 Outcome measures (ARRIVE 6)

3.8 Statistical methods (ARRIVE 7)

3.9 Experimental animals (ARRIVE 8)

3.10 Experimental procedures (ARRIVE 9)

3.11 Housing and husbandry (ARRIVE 15)

3.12 Animal care and monitoring (ARRIVE 16)

[Describe steps to reduce pain, suffering and distress; the expected and unexpected adverse events and how they were managed; and the humane end points with their criteria and the frequency of monitoring.]

4. Results (ARRIVE 10)

This section reports the numbers analysed and the outcomes.

4.1 Animals analysed

4.2 Outcomes

4.3 Adverse events

[Report all adverse events in each group, any modifications to procedures to reduce them, and animals reaching humane end points.]

5. Discussion

The discussion interprets the findings and their relevance.

5.1 Interpretation and scientific implications (ARRIVE 17)

[Interpret the results in light of the objectives and the literature. Discuss limitations, including sources of bias, limits of the model and imprecision. Describe any implications for replacement, refinement or reduction (the 3Rs).]

Example: A single dose of [compound] given 30 minutes after occlusion reduced infarct volume by about a third compared with vehicle. The estimate is imprecise, and the study was powered for one dose and one time point only. Efficacy in aged animals or animals with comorbidities, which better reflect the clinical population, was not tested.

5.2 Generalisability and translation (ARRIVE 18)

[Comment on whether, and how, the findings are likely to apply to other species, strains, sexes or experimental conditions, and their relevance to human biology.]

6. Other information

These items support transparency and reuse.

6.1 Protocol registration (ARRIVE 19)

[State whether a protocol, including the research question, key design features and analysis plan, was prepared before the study and whether and where it was registered, for example preclinicaltrials.eu or OSF.]

6.2 Data access (ARRIVE 20)

[Statement describing whether and where the study data are available, for example a public repository with a persistent identifier.]

6.3 Declaration of interests (ARRIVE 21)

7. Appendices

Supporting material for reviewers:

Standard and licence note

Based on the ARRIVE guidelines 2.0: Percie du Sert N, Hurst V, Ahluwalia A, et al., The ARRIVE guidelines 2.0: updated guidelines for reporting animal research (PLoS Biol 2020;18(7):e3000410), https://arriveguidelines.org. The guidelines are published open access under a Creative Commons Attribution licence; this template uses their item topics and numbering only, paraphrased in original text, and reproduces no checklist wording. Use the official checklist and the explanation and elaboration document when submitting. This is a reporting format, not veterinary, ethical or statistical advice; follow your national legislation and institutional animal welfare policy. Template licence: MIT.