Clinical Evaluation of a Royal Jelly Supplementation for the Restoration of Dry Eye: A Prospective Randomized Double Blind Placebo Controlled Study and an Experimental Mouse Model

<div><p>Background</p><p>Dry eye is a multifactorial disease characterized by ocular discomfort and visual impairment. Lacrimal gland function has been shown to decrease with aging, a known potent risk factor for dry eye. We have previously found that orally administrated royal jelly (RJ) restored tear secretion in a rat model of dry eye.</p><p>Methods and Findings</p><p>We examined the effects of RJ oral administration on dry eye in this prospective, randomized, double-blind, placebo-controlled study. Forty-three Japanese patients aged 20–60 years with subjective dry eye symptoms were randomized to an RJ group (1200 mg/tablet, six tablets daily) or a placebo group for 8 weeks. Keratoconjunctival epithelial damage, tear film break-up time, tear secretion volume, meibum grade, biochemical data, and subjective dry eye symptoms based on a questionnaire were investigated at baseline, and at 4 and 8 weeks after intervention. Adverse events were reported via medical interviews. In the RJ group, tear volume significantly increased after intervention (<i>p</i> = 0.0009). In particular, patients with a baseline Schirmer value of ≤10 mm showed a significant increase compared with baseline volume (<i>p</i> = 0.0005) and volume in the placebo group (<i>p</i> = 0.0051). No adverse events were reported. We also investigated the effect of RJ (300 mg/kg per day) administration using a mouse model of dry eye. Orally repeated administration of RJ preserved tear secretion, potentially through direct activation of the secretory function of the lacrimal glands.</p><p>Conclusion</p><p>Our results suggest that RJ improves tear volume in patients with dry eye.</p><p>Trial Registration</p><p>Registered NO. the University Hospital Medical Information Network in Japan (UMIN000014446)</p></div

CONSORT flowchart.

<p>CONSORT flowchart.</p

Change in Schirmer (baseline, ≤10 mm) values in patients with dry eye symptoms who received royal jelly (RJ) or placebo (PB) tablet.

<p>Data represent mean ± standard deviation **<i>p</i><0.01, ***<i>p</i><0.005 vs. pre-treatment values Between-group score comparisons at each time point (baseline, week 4, and week 8) were performed using the Aspin-Welch test (†<i>p</i><0.05).</p

Effects of royal jelly (RJ) on dry eye symptoms assessed by ophthalmological examinations.

<p>Effects of royal jelly (RJ) on dry eye symptoms assessed by ophthalmological examinations.</p

Baseline characteristics of patients with dry eye who received placebo (PB) or royal jelly (RJ).

<p>Baseline characteristics of patients with dry eye who received placebo (PB) or royal jelly (RJ).</p

Change in Schirmer values in patients with dry eye symptoms who received royal jelly (RJ) or placebo (PB) tablets.

<p>Error bars represent standard deviation. **<i>p</i><0.01 vs. pre-treatment values.</p

Biochemical analyses for patients with dry eye symptoms who received royal jelly (RJ) or placebo (PB) tablets.

<p>Biochemical analyses for patients with dry eye symptoms who received royal jelly (RJ) or placebo (PB) tablets.</p