Aerobic exercise increases tear secretion in type 2 diabetic mice.

Area of Science:

• Ophthalmology
• Endocrinology
• Exercise Physiology

Background:

• Type 2 diabetes can impair tear secretion, contributing to dry eye disease.
• Oxidative stress plays a role in the pathogenesis of diabetic complications, including ocular surface issues.
• Adenosine monophosphate-activated protein kinase (AMPK) is a key cellular energy sensor implicated in metabolic regulation.

Purpose of the Study:

• To evaluate the impact of exercise on tear secretion in type 2 diabetic mice.
• To determine the effect of an AMPK activator, AICAR, on tear secretion.
• To investigate the relationship between exercise, oxidative stress markers, and tear production.

Main Methods:

• Type 2 diabetic (db/db) and control (db/m) mice underwent 8 weeks of treadmill exercise or remained sedentary.
• Tear secretion volume was measured using cotton threads before and after the intervention.
• Tear oxidative stress markers (8-OHdG, PRL, HEL) were quantified.
• Mice received daily intraperitoneal injections of AICAR or PBS for 5 days to assess its direct effect on tear secretion.

Main Results:

• Eight weeks of exercise training significantly increased tear secretion in both diabetic and control mice.
• Exercise intervention led to reduced levels of oxidative stress markers in tears.
• AICAR administration significantly enhanced tear secretion in healthy and diabetic mice compared to placebo.
• Higher doses of AICAR demonstrated a more pronounced increase in tear secretion.

Conclusions:

• Both exercise training and AICAR administration effectively increase tear secretion in mice.
• Exercise may serve as a therapeutic strategy for managing tear secretion abnormalities.
• Targeting AMPK pathways could offer novel approaches for treating conditions associated with reduced tear production.