Abstract
There is little information on the effects of exposure to light emitting diode (LED) illumination on the welfare of laboratory animals. Nesfatin-1, a satiety-regulation peptide present in various tissues, is found in the central nervous system and participates in the stress response. The present study investigated whether exposure to blue and white LED lights for 14 weeks affected growth and reproductive, biochemical and histopathological parameters in male Sprague Dawley (SD) rats as well as whether subcutaneous (SC) injection of nesfatin-1 (0.5 mg/kg bodyweight) in the last two weeks of the experimental period alleviated these effects. Forty male SD rats (21 days of age) were randomly allotted to 6 groups. The animals were exposed to routine fluorescent light (the control [C] and control + sesame oil [CS] groups) or blue/white LEDs (the blue-LED and white-LED groups), accompanied by nesfatin-1 administration (the blue-LED-N1 and white-LED-N1 groups). White-LED rats had significantly higher testis weights (p < 0.05) than control and blue-LED rats. Serum melatonin levels were significantly lower in blue-LED rats, but nesfatin-1 injection rescued melatonin levels in blue-LED-N1 rats (p < 0.05). Blue-LED rats showed the highest serum nesfatin-1 levels, but nesfatin-1 injection decreased nesfatin-1 levels in blue-LED-N1 rats (p < 0.0001). Blue-LED rats showed a significant reduction in sperm motility compared to the other groups (p < 0.0001). White and blue LED exposure caused significant negative histopathological changes in the testes, but nesfatin-1 administration reduced edema in the intertubular spaces, hyperemia in the interstitial cells, degeneration of spermatocytes and thinning of the tubular wall in the testicular tissues; these restorative effects were larger in blue-LED-N1 rats than white-LED-N1 rats. Blue and white LED exposures had negative effects on melatonin levels, testis weights and tissue health. Nesfatin-1 alleviated some of the negative effects of LED lighting.