The reporting quality of the interventional animal experiments in Chinese journals-based on the evaluated results of the Animals in Research: Reporting In Vivo Experiments (ARRIVE) guidelines

Objective To evaluate retrospectively the reporting quality of animal experiments published in Chinese journals adhering to the Animals in Research: Reporting In Vivo Experiments (ARRIVE) guidelines. ≤ only 29.04% The assessment showed that the compliance of more than of sub-items (51.28%, 20/39) less than 50% and 65.00% (13/20) of sub-items than an accurate summary of the background, research objectives (including details of the species or strain of animal used), key methods, principal findings, and conclusions


Introduction
The animal experiment is the scientific research by using of animals in experiments to acquire new knowledge about biology and medicine or solve specific problems in laboratories [1] , which is one of the basic measures of biomedical researches. The animal experiment is an important part of preclinical research. As a bridge between basic research and clinical trials, the quality of animal experiments affects the achievements and level of researches in many fields [ 2,3] .
In recent years, the number of animal experiments published in biomedical journals has increased dramatically. But more and more studies showed that [4][5][6][7] , even in animal experiments published in top journals, the quality of their reports is still not satisfactory.
Studies by The National Centre for the Replacement, Refinement and Reduction of Animals in Research, NC3Rs [8] showed: many animal experiments with funding had inadequate reports on important information such as study design, implementation and analysis. In 271 included animal experiments, 41% of them did not state the hypothesis or objective of the study and the number and basic characteristics of the animals used in experiments, 30% of them did not describe the statistical methods and not present the results with correct statistical indicators. The inadequacy and incompleteness of the quality of articles and poor quality of reports have seriously hindered the utilization of the scientific and practical value of animal experiments. Therefore, in order to improve the quality of animal experimental reports, based on the COSORT Statement [9] , NC3Rs developed the ARRIVE guidelines (Animal Research Reporting: In Vivo Experiments Guidelines), which were published in 2010. The guideline consists of six parts: title, abstract, introduction, methods, results and discussion, with 20 items and sub-items [10] . Since 2010, scholars outside China have studied the quality of animal experiment reports published in foreign journals based on the ARRVE guidelines [11,12] , whereas in China, the similar research only can be found from Liu et al. [13] . Moreover, their research is limited to specific diseases. In addition, there is no study to explore whether the publication of the ARRIVE guidelines has improved the quality of animal experiment reports or not.
Therefore, this study collected comprehensively animal experiments published in China, reviewed and analyzed the quality of animal experimental reports and existing problems based on the ARRVE guidelines, so as to provide a reference for promoting the quality of animal experimental reports in China.

Patient and Public Involvement
There are not patients and or public involved the study.

Inclusion and Exclusion criteria
Inclusion criteria Intervention animal experiments, no restriction/limitation for animal species and the type of intervention.

Quality assessment of the included studies
Two well-trained reviewers (BZ and YBJ) assessed the quality of the included studies based on 39 sub-items of 20 items included in the ARRIVE guidelines. The evaluation results for each sub-item in the studies were "high risk" or "low risk", in which "low risk" means the studies to be evaluated reports all or part, or at least one of the information involved in the sub-items in detail. On the contrary, it was "high risk". Finally, the compliance rate of "low risk" for 39 sub-items was calculated, i.e. the total number of studies with "low risk" accounted for the percentage of the total number of included studies. respectively.

Statistical analysis
Data were analyzed using SPSS (v21.0, SPSS, Chicago, IL). Categorical data were represented by frequency (n) and percentage (%). Chi-square test was performed to compare percentage between groups and P-value 0.05 was considered to be statistically significant.

Selecting process and results
21713 potentially relevant studies were selected initially. After excluding duplicates and those that is not fulfil the inclusion criteria, 4342 studies were included finally, in which there were 4925 animal experiments (some included multiple animal experiments). The selecting process and results are shown in Figure 1.

Epidemiological Characteristics
Frequency of citation of each inclusive study ranged from 0 to 12; more than 70%  11b Describe the order in which the animals in the different experimental groups were treated assessed. Experimental outcomes 12 Clearly define the primary and secondary experimental outcomes assessed (e.g., cell deat molecular markers, behavioral changes). Statistical methods 13a Provide details of the statistical methods used for each analysis.
13b Specify the unit of analysis for each dataset (e.g. single animal, group of animals, single n 13c Describe any methods used to assess whether the data met the assumptions of the statist approach. RESULTS

Baseline data 14
For each experimental group, report relevant characteristics and health status of animals weight, microbiological status, and drug-or test-naı¨ve) before treatment or testing (this information can often be tabulated). Numbers analysed 15a Report the number of animals in each group included in each analysis. Report absolute nu (e.g.10/20, not 50%) 15b If any animals or data were not included in the analysis, explain why.
Outcomes and estimation 16 Report the results for each analysis carried out, with a measure of precision (e.g, standard confidence interval). Adverse events 17a Give details of all important adverse events in each experimental group.
17b Describe any modifications to the experimental protocols made to reduce adverse events. The ARRIVE guidelines have 6 sections with 20 items and 39 sub-items. In terms of this, the "low risk" compliance rate of more than half of sub-items (51.28%, 20/39) is less than 50%, of which the "low risk" compliance rate of 90% (18/20) is less than 30%., even 65% (13/20) is less than 10%; only 28.21% (11/39) is higher than 90%.

DISCUSSION
In terms of 2 items (items 1-2) involved in the title and abstract, the "low risk" compliance rate of items 1 and 2 is higher than 90%. The "low risk" compliance rate of items 1 and 2 in studies published after 2010 is higher than that of studies published before 2010, and the difference between two groups in item 1 (P= 0.012) and 2 (P < 0.001) have statistical significance.
In terms of 3 items (items 3a-4) involved in abstract the "low risk" compliance rate of items 3a and 4 is higher than 90%, and the "low risk" compliance rate of item 3b is only 37.06%. The "low risk" compliance rate of items 3a, 3b and 4 in studies published after 2010 is higher than that of studies published before 2010, and the difference between two groups in items 3a (P< 0.001), 3b (P< 0.001) and 4 (P= 0.003) have statistical significance.
The "low risk" compliance rate of items 14, 15a, 15b, 16 and 17a in studies published after 2010 is all higher than that of studies published after 2010. The differences between two groups in items 14 (P < 0.001), 16 (P < 0.001) and 17a (P = 0.002) have statistical significance, but in items 15a (P = 0.063) and 15b (P = 0.402) have none of statistical significance; whereas, the differences between two groups in item 17b (P = 0.337) have none of statistical significance.
In items of 5 items (items 18a-20) involved in discussion, except for the "low risk" compliance rate of items 18a is more than 90%, the "low risk" compliance rate of the other items is all less than 10%. The "low risk" compliance rate of 5 items in studies

Discussion
This is the first comprehensive and systematic study on the reporting quality of animal experiments published in Chinese journals based on the ARRIVE guidelines. Overall, with the publication of the ARRIVE guidelines, the compliance rate of most items in the ARRIVE guidelines has been improved to a certain extent in published animal experiments in China. However, there are still inadequacy in reports of some specific items, e.g. study design, procedures, sample size, adverse events and discussion.
②Study design: After 2010, although more studies used time-line diagrams or flow charts to illustrate the whole process of study designs and conducting (item 6d), the actual compliance rate was only 2.31%. Some studies have shown that more than half of the preclinical studies are unrepeatable [16] , the main reasons of which include deficiencies in study designs, incorrect statistical analysis and inadequate reporting [8,17,18] . Therefore, a clear and detailed flow chart can effectively show the whole process of the experiment and improve the transparency of the whole process of the experiment implementation.
③Experimental procedures: Of the animal studies published in Chinese journals, only 6.20% and 11.81% studies provided experimental dates (item 7b) and experimental sites (item 7c). A study [19] showed that 76 animal experiment articles (with more than 500 citations) were unable to scientifically evaluate the reliability of the results because of the lack of reports on key methodological information including experimental process and procedures. Therefore, the detailed report of the experimental process and procedures is the key measure to ensure the replication of the results and to improve the utilization and conversion rate of the results.
④Housing and husbandry conditions: Although the research published after 2010 showed that the compliance rate of housing (item 9a) and husbandry conditions (item 9b) was effectively improved (P < 0.001), the actual compliance rate was only 29.46% and 28.35% respectively. It is well known that type of cage or housing, style of settlement, light/dark cycle, temperature and water quality will have an important impact on the experimental results. In addition, Hooijmans et al. [2,20,22] pointed out in their research that there can be a four-fold difference in light intensity between cages at the top or bottom of a rack, and small differences in the light intensity have been associated with animal reproduction and behavior. on how to improve making animal research reports in the process of submitting articles and using funding, in which NIMDS noted [23] : insufficient sample size may lead to false negative results, and miss some potentially important discoveries. Therefore, it is necessary to report how many animals are used in each group and what statistical methods are used to determine the sample size.
⑥Allocating animals to experimental groups: Although the reporting rate of specific grouping methods for experimental animals published after 2010 (item 11a) was significantly higher than that published before 2010 (P < 0.001), the actual coincidence rate was only 12.02%. Some studies have shown [8] that randomization, allocation concealment and blinding are important methods to reduce the risk of the bias in an intervention animal experiment.

Results and discussion
In the ARRIVE Guidelines, the results and discussion sections include "baseline data, numbers analyzed, outcomes and estimation, adverse events, interpretation/scientific implications, generalizability/translation, and funding". Our research shows that: any potential source of bias in the experimental process, and any factors affecting the accuracy of the study results will reduce the scientific content of the study [10] . Therefore, it is necessary for the author to objectively evaluate and explain it in the discussion part of the articles in order to ensure the scientific nature of its valid conclusion and help the users of evidences to grasp and understand its conclusion. In addition, the implementation of animal experiments should follow the 3Rs (replacement, refinement and reduction of animals in research), and the core of which is to protect, use less or use no animals [1,24] .
Scientific experimental design can reduce the number of experimental animals [25,26] .
Refined experimental technology route and optimized research proposal can allay and reduce pain and anxiety of animals in the experimental process [24] . Therefore, it is necessary for the author to interpret the scientific connotation in the discussion section of the paper, which can help readers fully obtain and evaluate the research information, In summary, the reporting quality of animal experiments based on ARRIVE guidelines in China is generally low to moderate level. Particularly, insufficient reporting in methods, including ethical statement, study design, experimental procedures, sample size, and allocating animals to experimental groups, makes the evidence users fail to fully understand the whole process of study design and implementation and, to a certain extent, hinder the transformation and utilization of research achievements. Therefore, it is necessary to popularize ARRIVE guidelines and encourage researchers to follow ARRIVE guidelines in the future, especially to promote the introduction of ARRIVE guidelines in specialized journals so as to promote the design, implementation and reporting of animal experiments, and ultimately improve their quality.

Data Availability Statement
All relevant data are with in the paper and its Supporting Information files.  The species laboratory animals and interventions of animal test reports published in Chinese journals. References

Supplementary Files
This is a list of supplementary files associated with the primary manuscript. Click to download. S1 File.docx