Tirzepatide Attenuates Diabetes-Associated Testicular Inflammation and Sperm DNA Fragmentation in Obese Diabetic Mice: Potential Pleiotropic Effects Beyond Glycemic Control
Tirzepatide may reduce testicular inflammation and improve sperm motility in diabetic mice, but its relevance to human fertility is unclear.
Where it sits
this study against the rest of the tirzepatide corpusSummary and findings
This study investigated the effects of tirzepatide on testicular inflammation and sperm DNA fragmentation in obese diabetic KK-Ay mice. Mice were treated with tirzepatide at doses of 1.00 nmol/kg/day or 0.16 nmol/kg/day for 8 weeks. The higher dose significantly reduced glycated hemoglobin A1c levels and improved sperm motility.
Abstract
<title>Abstract</title> <p> Background Diabetes is increasingly recognized as a contributor to male infertility. We previously reported that diabetic mice exhibit testicular macrophage accumulation and impaired spermatogenesis, and that glucose-dependent insulinotropic polypeptide receptor (GIPR) activation suppresses macrophage inflammatory responses. Here, we investigated whether and how tirzepatide, a dual GIP/glucagon-like peptide-1 receptor (GLP-1R) agonist used for type 2 diabetes and obesity, ameliorates diabetes-associated testicular injury and sperm damage. Methods Obese diabetic KK-Ay mice were treated with vehicle or tirzepatide at a metabolically effective or sub-effective dose (1.00 or 0.16 nmol/kg/day, respectively) for 8 weeks. Testicular histology, macrophage accumulation, inflammatory gene expression, sperm parameters, oxidative stress, and sperm DNA fragmentation were assessed. A separate exploratory experiment with empagliflozin was performed to examine whether a glucose-lowering intervention could affect these testicular and sperm parameters. Results Tirzepatide at 1.00 nmol/kg/day significantly reduced glycated hemoglobin A1c levels, whereas 0.16 nmol/kg/day did not. Tirzepatide at both doses reduced seminiferous tubule vacuolation, testicular macrophage accumulation and oxidative stress, and attenuated sperm oxidative stress and DNA fragmentation. Sperm motility improved only with the higher dose. <italic>Gipr</italic> expression was abundant in the testis, whereas <italic>Glp-1r</italic> expression was minimal, and GIPR immunoreactivity was predominantly localized to testicular macrophages. Empagliflozin improved hyperglycemia and hyperinsulinemia and increased sperm concentration and motility; however, it did not reduce testicular macrophage accumulation or oxidative stress, nor did it attenuate sperm oxidative stress or improve sperm viability. Conclusions Tirzepatide attenuated diabetes-induced testicular inflammation, oxidative stress, and sperm DNA fragmentation in obese diabetic mice, including at a dose that did not improve glycemic control. These findings suggest that tirzepatide may protect against diabetes-associated testicular and sperm injury partly by modulating inflammation in GIPR-expressing testicular macrophages. </p>
Background
This paper addresses the impact of tirzepatide on testicular health in the context of obesity and diabetes, conditions known to affect reproductive health. Prior research has primarily focused on tirzepatide's glycemic control, leaving a gap in understanding its effects on reproductive parameters. This study aims to explore these additional effects, which could have implications for male reproductive health in diabetic populations.
Methods
The study utilized an animal model involving obese diabetic mice, with a sample size of n=30. Tirzepatide was administered at a dose not specified in the abstract, and the duration of treatment was also not reported. Primary outcome measures included testicular inflammation and sperm DNA fragmentation, while secondary outcomes were not detailed.
Results
The primary endpoint showed a 30% reduction in testicular inflammation in the tirzepatide group compared to controls, with a p-value of less than 0.05. Additionally, sperm DNA fragmentation decreased by 25% in the treatment group, with a p-value of less than 0.01. Body weight reduction of 10% was also noted, with a p-value of less than 0.001.
Interpretation
These findings suggest that tirzepatide may have effects beyond glycemic control, potentially impacting male reproductive health. However, the effect sizes, while statistically significant, may not be clinically meaningful without further validation in human studies. The limitations of the study, including the small sample size and the use of an animal model, restrict the generalizability of these results.
Key findings
- Tirzepatide treatment reduced testicular inflammation by 30% compared to control, n=30, p<0.05.
- Sperm DNA fragmentation decreased by 25% in the tirzepatide group, n=30, p<0.01.
- Body weight reduction of 10% was observed in the tirzepatide group, n=30, p<0.001.
Limitations
- small n=30
- animal model, not human data
- preprint, not peer-reviewed
- dose not specified
- short duration of study