Taurine influences the phagocytic function of retinal pigment epithelium cells in healthy and dystrophic animals

Aims/Purpose: To investigate the influence of taurine on the phagocytic function of the retinal pigment epithelium (RPE) in normal and dystrophic rats. Methods: Normal albino Sprague–Dawley (SD) and pigmented dystrophic Royal College of Surgeons (RCS‐p+) rats that suffer an inherited photoreceptor degeneration due to RPE phagocytosis impairment were used for the study. Taurine depletion was induced in SD rats (n = 8) by providing β‐alanine in drinking water (3%) from postnatal day 21 (P21). Taurine supplementation was administered to RCS‐p+ rats (n = 8) in drinking water (0.2 M) from P21. Untreated RCSp+ (n = 8) and SD (n = 8) rats served as control groups. Rats were processed at P81 (SD) and at P45 (RCS) and received an intravitreal injection (IV) of. 1.5 μL of Fluorogold (FG, 3%) diluted in saline 24 h before processing. The RPE was dissected, flat‐mounted and immunodetected with anti‐S opsin antibodies to label the RPE phagosomes which were quantified using ImageJ and size criteria. Results: The mean numbers (± SD) of phagosomes per RPE whole mount was 414 ± 118 in control SD rats, 1034 ± 528 in taurine‐depleted SD rats 88 ± 12 in untreated RCS and 119 ± 9 in taurine‐treated RCS rats. The numbers of phagosomes were significantly higher in SD rats than in RCS‐p+ rats (t‐test, p