The effects of the light spectrum on the reproductive system and epididymal semen quality of pubertal male rats.

Light is one of the factors affecting physiological functions in living things. In the present study, reproductive functions of male rats exposed to different wavelengths of light were evaluated. For this purpose, a total of 56 male Sprague Dawley rats were used in 7 groups (n = 8 per group). Rats were exposed to light spectrum with different wavelengths for 63 days. It was observed that malondialdehyde levels were lower in the orange (2.77 ± 0.16 nmol*mL-1), red (4.27 ± 0.17 nmol*mL-1), yellow (5.14 ± 0.15 nmol*mL-1) and green (5.56 ± 0.40 nmol*mL-1) coloured light group compared to the other groups [purple (7.07 ± 0.96 nmol*mL-1), blue (7.52 ± 0.89 nmol*mL-1), white (8.59 ± 1.20 nmol*mL-1)] (P < 0.001). The lowest glutathione levels were observed in purple (86.82 ± 1.63 nmol mL-1), blue (101.25 ± 3.61 nmol*mL-1), yellow (105.44 ± 1.70 nmol*mL-1) and green (108.11 ± 0.51 nmol*mL-1) coloured groups, respectively. The lowest sperm motility percentage was found in blue (29.16 ± 11.40), purple (56.25 ± 3.36), green (62.50 ± 4.91) and white (69.58 ± 5.51) coloured light groups compared to the other groups (P < 0.001). Epididymal sperm density decreased significantly in rats exposed to purple, orange and blue light (P < 0.001). The abnormal sperm ratio was higher in the blue and white light group compared to the other groups (P < 0.001). Histological examinations showed that tubulus seminiferus contortus diameter and germinal cell thickness decreased significantly in the purple light treatment (P < 0.001). As a summary, the application of purple and blue light has negative effects on the reproductive function in rats.