Reporting of 3Rs Approaches in Preclinical Animal Experimental Studies-A Nationwide Study

The 3Rs aim to refine animal welfare, reduce animal numbers, and replace animal experiments. Investigations disclose that researchers are positive towards 3Rs recommendations from peers. Communication of 3Rs approaches via primary preclinical animal experimental literature may become a fast-forward extension to learn relevant 3Rs approaches if such are reported. This study investigates 3Rs-reporting in peer-reviewed preclinical animal research with at least one author affiliated to a Danish university. Using a systematic search and random sampling, we included 500 studies from 2009 and 2018. Reporting was low and improvement over time limited. A word search for 3R retrieved zero results in 2009 and 3.2% in 2018. Reporting on 3Rs-related sentences increased from 6.4% in 2009 to 18.4% in 2018, "reduction" increased from 2.4% to 8.0%, and "refinement" from 5.2% to 14.4%. Replacement was not reported. Reporting of the methodology was missing. For "reduction", methodology was mentioned in one study in 2009 and 11 studies in 2018, and for "refinement" in 9 and 21, respectively. Twenty-one studies stated compliance with ARRIVE-guidelines or similar without disclosure of details. Reporting of 3Rs approaches in preclinical publications is currently insufficient to guide researchers. Other strategies, e.g., education, interdisciplinary collaboration, and 3Rs funding initiatives, are needed.

Rat pancreatectomy combined with isoprenaline or uninephrectomy as models of diabetic cardiomyopathy or nephropathy

Cardiovascular and renal complications are the predominant causes of morbidity and mortality amongst patients with diabetes. Development of novel treatments have been hampered by the lack of available animal models recapitulating the human disease. We hypothesized that experimental diabetes in rats combined with a cardiac or renal stressor, would mimic diabetic cardiomyopathy and nephropathy, respectively. Diabetes was surgically induced in male Sprague Dawley rats by 90% pancreatectomy (Px). Isoprenaline (Iso, 1 mg/kg, sc., 10 days) was administered 5 weeks after Px with the aim of inducing cardiomyopathy, and cardiac function and remodeling was assessed by echocardiography 10 weeks after surgery. Left ventricular (LV) fibrosis was quantified by Picro Sirius Red and gene expression analysis. Nephropathy was induced by Px combined with uninephrectomy (Px-UNx). Kidney function was assessed by measurement of glomerular filtration rate (GFR) and urine albumin excretion, and kidney injury was evaluated by histopathology and gene expression analysis. Px resulted in stable hyperglycemia, hypoinsulinemia, decreased C-peptide, and increased glycated hemoglobin (HbA1c) compared with sham-operated controls. Moreover, Px increased heart and LV weights and dimensions and caused a shift from α-myosin heavy chain (MHC) to β-MHC gene expression. Isoprenaline treatment, but not Px, decreased ejection fraction and induced LV fibrosis. There was no apparent interaction between Px and Iso treatment. The superimposition of Px and UNx increased GFR, indicating hyperfiltration. Compared with sham-operated controls, Px-UNx induced albuminuria and increased urine markers of kidney injury, including neutrophil gelatinase-associated lipocalin (NGAL) and podocalyxin, concomitant with upregulated renal gene expression of NGAL and kidney injury molecule 1 (KIM-1). Whereas Px and isoprenaline separately produced clinical endpoints related to diabetic cardiomyopathy, the combination of the two did not accentuate disease development. Conversely, Px in combination with UNx resulted in several clinical hallmarks of diabetic nephropathy indicative of early disease development.

Evaluation of microRNA stability in feces from healthy dogs

BACKGROUND

Gastrointestinal cancer accounts for approximately 8% of all canine malignancies. Early detection of cancer may have a tremendous impact on both treatment options and prognosis. MicroRNAs (miRNAs), a class of noncoding RNAs that can be found stably expressed in body fluids and feces, have been suggested as valuable human cancer biomarkers.

OBJECTIVES

The purpose of the study was to investigate the feasibility of detecting miRNAs in canine feces and to determine the miRNA stability in fecal samples stored at different temperatures for different duration.

METHODS

The levels of 4 Canine familiaris (cfa) miRNAs (cfa-miR-16, cfa-miR-20a, cfa-miR-21, and cfa-miR-92a) were investigated by quantitative real-time PCR(qPCR) in fecal samples from 10 healthy dogs. Fecal samples were collected at 3 different time points and samples from the first time point were stored at different temperatures and for a different duration.

RESULTS

A statistically significant difference was found in miRNA levels from samples stored at room temperature compared with samples stored at -20°C for cfa-miR-16 and cfa-miR-21. No significant difference was found in the level of the investigated miRNAs over time.

CONCLUSIONS

Overall, miRNAs are present in dog feces at measurable levels. Some miRNAs seem to be subject to a higher degree of degradation in samples stored at room temperature for 24 hours compared with samples frozen after collection at -20°C. The investigated miRNAs were stably expressed over time. This study provides the basis for further research on miRNA expression profiles as biomarkers for gastrointestinal cancer in dogs.