# Exogenous Melatonin Attenuates Sleep Restriction-Induced Kidney Injury via Gut Microbiota-Derived Propionate in Mice

## TL;DR

Exogenous melatonin helps protect against kidney damage caused by sleep restriction in mice, likely through gut microbiota-derived propionate.

## Contribution

The study reveals a novel gut–kidney axis in sleep restriction-induced kidney injury and the protective role of melatonin via propionate.

## Key findings

- Exogenous melatonin mitigates sleep restriction-induced kidney injury in mice.
- Microbiota depletion reverses the protective effect of melatonin on kidney injury.
- Propionic acid supplementation reduces kidney injury caused by sleep restriction.

## Abstract

Chronic sleep restriction (SR) impairs multiple organs. Although exogenous melatonin counteracts SR-induced gut microbiota disruption, its role in protecting renal function and the involvement of gut microbiota remain unclear. To this end, we subjected mice to a 28-day SR paradigm with exogenous melatonin treatment or antibiotic-induced microbiota depletion. SR mice demonstrated significant renal dysfunction evidenced by elevated serum creatinine, blood urea nitrogen, and uric acid levels compared to controls. Histopathological analysis revealed characteristic tubular abnormalities in SR mice, including epithelial degeneration and lumen dilation, with reduced expression of key renal filtration markers (Nephrin, Podocin, CD2-associated protein, and α-Actinin-4). All of these could be mitigated by melatonin treatment, and all changes were statistically significant (p < 0.05 or p < 0.01). Intriguingly, microbiota depletion significantly reversed the protective effect of exogenous melatonin on kidney injury in SR mice, while propionic acid supplementation mitigated SR-induced kidney injury. Furthermore, we found that gut microbiota and the metabolite propionic acid mediated the role of exogenous melatonin probably through attenuating SR-induced renal oxidative damage, including regulating renal superoxide dismutase (SOD) activity, total antioxidant capacity (T-AOC), and malondialdehyde (MDA) level. These findings collectively indicated that melatonin may ameliorate SR-associated kidney injury through gut microbiota-derived propionic acid. Our finding highlights a novel gut–kidney axis in SR-related pathophysiology.