Animals (Basel) 2022 Oct 25;12(21):2927.doi: 10.3390/ani12212927.

Generalizability, Robustness and Replicability When Evaluating Wellbeing of Laboratory Mice with Various Methods

Dietmar Zechner  ¹ , Benjamin Schulz  ¹ , Guanglin Tang  ¹ , Ahmed Abdelrahman  ¹ , Simone Kumstel  ¹ , Nico Seume  ¹ , Rupert Palme  ² , Brigitte Vollmar  ¹

¹ Rudolf-Zenker-Institute of Experimental Surgery, Rostock University Medical Center, 18057 Rostock, Germany.

² Unit of Physiology, Pathophysiology and Experimental Endocrinology, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, 1210 Vienna, Austria.

Abstract

An essential basis for objectively improving the status of animals during in vivo research is the ability to measure the wellbeing of animals in a reliable and scientific manner. Several non-invasive methods such as assessing body weight, burrowing activity, nesting behavior, a distress score and fecal corticosterone metabolites were evaluated in healthy mice and after three surgical interventions or during the progression of four gastrointestinal diseases. The performance of each method in differentiating between healthy and diseased animals was assessed using receiver operating characteristic curves. The ability to differentiate between these two states differed between distinct surgical interventions and distinct gastrointestinal diseases. Thus, the generalizability of these methods for assessing animal wellbeing was low. However, the robustness of these methods when assessing wellbeing in one gastrointestinal disease was high since the same methods were often capable of differentiating between healthy and diseased animals independent of applied drugs. Moreover, the replicability when assessing two distinct cohorts with an identical surgical intervention was also high. These data suggest that scientists can reach valid conclusions about animal wellbeing when using these methods within one specific animal model. This might be important when optimizing methodological aspects for improving animal wellbeing. The lack of generalizability, however, suggests that comparing animal models by using single methods might lead to incorrect conclusions. Thus, these data support the concept of using a combination of several methods when assessing animal welfare.

Front Nutr 2022 Aug 10;9:935805.doi: 10.3389/fnut.2022.935805. eCollection 2022.

The effect of different weight loss strategies to treat non-alcoholic fatty liver disease focusing on fibroblast growth factor 21

Nicole Power Guerra  ^{1   2} , Katharina Leyens  ¹ , Luisa Müller  ^{1   3} , David Brauer  ⁴ , Deborah Janowitz  ^{5   6} , Samin Schlick  ^{5   6} , Kristin Pilz  ⁵ , Hans J Grabe  ⁵ , Brigitte Vollmar  ¹ , Angela Kuhla  ¹

¹ Institute for Experimental Surgery, Rostock University Medical Center, Rostock, Germany.

² Institute of Anatomy, Rostock University Medical Center, Rostock, Germany.

³ Department of Psychosomatic Medicine, Rostock University Medical Center, Rostock, Germany.

⁴ Department of Systems Biology and Bioinformatics, University of Rostock, Rostock, Germany.

⁵ Department of Psychiatry, University Medicine Greifswald, Greifswald, Germany.

⁶ Clinic for Psychiatry and Psychotherapy, HELIOS Hanseklinikum Stralsund, Stralsund, Germany.

Abstract

Objective: Obesity, often associated with non-alcoholic fatty liver disease (NAFLD), is characterized by an imbalance between energy expenditure and food intake, which is also reflected by desensitization of fibroblast growth factor 21 (FGF21). FGF21 is strongly influenced, among others, by TNFα, which is known to be upregulated in obesity-induced inflammation. Successful long-term treatments of NAFLD might be dietary modification, exercise, or fasting.

Materials and methods: Whether succeeded NAFLD recovery is linked with improved FGF21 sensitivity and finally reverted FGF21 resistance was the focus of the present study. For this purpose, mice received a high-fat diet (HFD) for 6 months to establish obesity. Afterward, the mice were subjected to three different weight loss interventions, namely, dietary change to low-fat diet (LFD), treadmill training, and/or time-restricted feeding for additional 6 months, whereas one group remained on HFD.

Results: In addition to the expected decrease in NAFLD activity with dietary change, this was also observed in the HFD group with additional time-restricted feeding. There was also an associated decrease in hepatic TNFα and FGF21 expression and an increase in ß-klotho expression, demonstrated mainly by using principal component analysis. Pearson correlation analysis shows that independent of any intervention, TNFα expression decreased with improved NAFLD recovery. This was accompanied with higher FGF21 sensitivity, as expressed by an increase in β-klotho and FGFR1c expression and concomitantly decreased FGF21 levels.

Conclusion: In summary, we conclude that successful NAFLD therapy is associated with a reversion of the TNFα-triggered FGF21-resistant state or desensitization.

Keywords: FGF21; TNFα; dietary change; high-fat diet; non-alcoholic fatty liver disease; time-restricted feeding; treadmill exercise; β-klotho.