Table 4.
Summary of the effects of constant light (LL) on the immune parameters under steady state and challenged conditions in rodents.
| Species | LL Intensity and Duration |
Immune Challenge | Effects | Ref. |
|---|---|---|---|---|
| Sprague-Dawley rats | 300 lx for 17 weeks and 16 weeks of re-synchronization |
Lost 24 h rhythm in blood leukocytes after 11/16 weeks in LL, (the rhythm was not restored after 16 weeks of re-synchronization in LD regime) ↓ NK cell counts in the blood |
[158] | |
| Wistar rats | 150 lx for 4 weeks | Activated pro-inflammatory state (↑ expression of Stat3, Il-1α and Il-17ra) in the colonic mucosa | [151] | |
| Wistar rats | 200–250 lx for 5 weeks | LPS 2 µg/kg (i.v.) | ↑ plasma TNFα response and sickness symptoms upon LPS | [152] |
| Wistar rats | 200–250 lx for 5 weeks | C6 tumor cells (s.c.) | ↑ tumor growth ↑ tumor infiltration of monocytes/macrophages |
[152] |
| Sprague-Dawley rats | 200 lx for 7 days | Endotoxemia model (daily i.p. LPS injection for 7 days) |
↑ hypothalamic expression of Il-1β and Tnfα | [159] |
| C56BL/6J mice | 105 lx for 24 weeks | LPS 50 µg/kg (i.v.) | Transient ↑ of neutrophil and ↓ of lymphocyte numbers in the blood was associated with enhanced inflammatory response to LPS (↑ IL-1β, TNFα, IL-6, and ↓ IL-10 plasma levels) after 8 weeks of LL No immune changes after 24 weeks of LL |
[154] |
| CD-1 mice | 750 lx for 4 weeks | Complete Freund’s adjuvant (100 µL) | ↑ proportion of myeloid-derived suppressor cells in the spleen under LL was potentiated by chronic inflammation ↑ plasma TGF-β1 levels and ↑ chronic inflammation induced elevation of IL-6 levels |
[160] |
IL—interleukin; LD—light/dark; LPS—lipopolysaccharide; STAT3—signal transducer and activator of transcription 3; TGF-β1—transforming growth factor beta 1; TNFα—tumor necrosis factor-alpha.