Long-term high fructose intake promotes lacrimal gland dysfunction by inducing gut dysbiosis in mice

The lacrimal gland is essential for maintaining ocular surface health through the secretion of the aqueous layer of the tear film. It is therefore important to explore the intrinsic and extrinsic factors that affect the structure and function of the lacrimal gland and the mechanisms underlying them. With the prevalence of Westernized diets characterized by high sugar and fat content, the susceptibility to many diseases, including ocular diseases, is increased by inducing dysbiosis of the gut microbiome. Here, we found that the composition, abundance, and diversity of the gut microbiome was significantly altered in mice by drinking 15% high fructose water for one month, as determined by 16S rRNA sequencing. This was accompanied by a significant increase in lipid deposition and inflammatory cell infiltration in the extraorbital lacrimal glands (ELGs) of mice. Transcriptome analysis based on bulk RNA-sequencing revealed abnormal activation of some of several metabolic and immune-related pathways. In addition, the secretory response to stimulation with the cholinergic receptor agonist pilocarpine was significantly reduced. However, when the composition and diversity of the gut microbiome of high fructose intake (HFI)-treated mice were improved by transplanting feces from normal young healthy mice, the pathological alterations in ELG structure, inflammatory cell infiltration, secretory function and transcriptome analysis described above were significantly reversed compared to age-matched control mice. In conclusion, our data suggest that prolonged HFI may cause pathological damage to the structure and function of the ELG through the induction of gut dysbiosis. Restoration of intestinal dysbiosis in HFI-treated mice by fecal transplantation has a potential role in ameliorating these pathological impairments.