AIM:To investigate the mechanism of reduced tear secretion in depression-related dry eye rats based on 5-HT/TRPV4/AQP5.

METHODS:Healthy SD male rats were established with chronic unpredictable mild stress(CUMS)method to establish a depression-induced dry eye model(n=8), and the control group was blank rats(n=8). The ELISA method was used to compare the 5-hydroxytryptamine(5-HT)in serum and hippocampal tissue of the two groups, and the HE sections of lacrimal gland and AQP5 immunohistochemistry were observed. Western blot and RT-PCR were used to detect the expression of 5-HT3R, TRPV4 and AQP5 in the lacrimal gland tissue of the two groups of rats.

RESULTS:The tear secretion in the depression-induced group was significantly reduced(P=0.001), the serum and hippocampal 5-HT levels were significantly reduced(all P<0.05), the expression of AQP5 antibody in the lacrimal gland immunohistochemistry was significantly lower than that in the control group(P<0.001), the expression of 5-HT3R, TRPV4 and AQP5 in the lacrimal gland was significantly reduced(all P<0.05), and no obvious inflammatory cells were found in the lacrimal gland tissue sections.

CONCLUSION:Depression-related dry eye may occur through a non-inflammatory 5-HT/TRPV4/AQP5 mechanism.