Effects of Lycium barbarum (goji berry) on dry eye disease in rats

Lycium barbarum (goji berry) has long been used as a food and traditional herbal medicine. This study aimed to investigate the beneficial effect of the goji berry on dry eye disease in rats. Male Sprague-Dawley rats with induced dry eye disease were randomly assigned to four groups: Vehicle (control), low-dose goji berry extract [GBE; 250 mg/kg/body weight (bw)], median-dose GBE (350 mg/kg/bw), and high-dose GBE (500 mg/kg/bw). Three methods, Schirmer's test, tear break-up time (BUT) measurement and keratoconjunctival fluorescein staining, were used to evaluate the effect of GBE on symptoms of dry eye disease experienced by the rats. The results of the present study revealed that both the Schirmer's test score and tear BUT significantly increased following 1 week of GBE administration. Furthermore, the severity of the keratoconjunctival staining decreased significantly. In addition, the results suggested that administration of GBE may ameliorate dry eye disease symptoms in a dose-dependent manner. There were no mortalities and no apparent abnormal histopathology changes in the liver or kidney tissues of rats administered GBE for 21 consecutive days. Polysaccharides and betaine present in GBE may have important effects in alleviating dry eye disease induced by oxidative stress and inflammation. In conclusion, the goji berry is a safe, functional food with beneficial effects in alleviating dry eye disease.