[Effect of lycopene on immunity in rats with acute lung injury].

Objective: To investigate the effects of lycopene on T lymphocyte subpopulations and pulmonary alveolar macrophagic (PAM) functions in rats with acute lung injury (ALI).

Methods: Rats were randomly divided into the following groups. (1) Control group, (2) ALI model group, (3) Low dose group,(4) Mid dose group and (5) High dose group. Control group and ALI model group were treated with solvent of lycopene, and the other groups were gastrically incubated with lycopene. Thirty-five days later, control group were given physiological saline, ALI model group and lycopene administrated groups were injected with lipopolysaccharide (LPS) (6.0 mg/kg) to induce ALI. One hour, four hours or six hours after LPS or physiological saline challenged, abdominal aorta blood for measuring lymphocyte subpopulations and bronchoalveolar lavage fluid for measuring function of PAM were gathered respectively.

Results: (1) At h 1, the percentages of CD3(+), CD4(+) and CD8(+) of lycopene administrated groups compared with control group were not significantly different. At h 4, the percentage of CD4(+) was similar to that at h 1. As for the percentages of CD3(+), except high dose group [(28.8+/-9.9)%] was significantly lower, low dose, mid dose and ALI model group showed no significant difference compared with control group[(39.5+/- 4.5)%]. The percentages of CD8(+) of ALI model and lycopene administrated rats, separately (10.2+/-3.9)%, (10.3+/-2.8)%, (9.8+/-2.8)%, (10.1+/-3.5)% , had been significantly reduced compared with control group[(15.1+/-2.5)%]; between ALI model and lycopene administrated groups there was no significant difference. The instance at h 6 was the same as that at h 4. The percentage ratios of CD4(+) T-lymphocyte to CD8(+) T-lymphocyte of ALI model rats were not significantly different compared with control group or lycopene administrated groups at h 1 and h 6. At h 4, the ratio of the CD4(+) and CD8(+) in Low dose and Mid dose groups had significant difference and ALI model, high dose hadn't when they were compared with control group. (2) Lycopene increased the phagocytic function of PAMs significantly at h 1(P<0.01), the optical density of PAM of control group, ALI model group, low dose group, mid dose group, high dose group was 0.136+/-0.025, 0.215+/-0.095, 0.239+/-0.052, 0.275+/-0.068 and 0.297+/-0.049; what happened at h 4 was similar to that at h 1; Phagocytic function of PAM of lycopene administrated groups was increased compared with control group. (3) The concentrations of tumor necrosis factor-alpha (TNF-alpha) in control group, ALI model group, low dose group, mid dose group, high dose groups were 1.50+/-0.30, 1.87+/-0.30, 1.76+/-0.40, 1.74+/- 0.38,1.62+/-0.35 microg/L;and those of IL-8 were 0.82+/-0.08, 0.99+/-0.14, 0.82+/-0.16, 0.84+/-0.16, 0.83+/-0.11 microg/L. The concentrations of TNF-alpha and interleukin-8 (IL-8) in BALF were decreased by lycopene, especially the levels of IL-8 were reduced significantly.

Conclusion: Lycopene might attenuate lipopolysaccharide-induced impairment of lungs and improve ALI prognosis by increasing the phagocytic function of PAMs significantly and restraining the secretion of TNF-alpha and IL-8.