Regulatory effect of melatonin on cytokine disturbances in the pristane-induced lupus mice

Abstract

Systemic lupus erythematosus (SLE) develops in relation to many environmental factors. In our opinion, it is more important to investigate the effect of melatonin on the environmental- related SLE. In the present study, 0.5 ml pristane were used to induce SLE in female BALB/c mice. Melatonin (0.01, 0.1, 1.0 mg/kg) was orally administered immediately after pristane-injection for 24 weeks. IgM anti ssDNA and histone antibodies were detected after 0, 1, 2, 4, 8 weeks pristane injection. The levels of IL-2, IL-6 and IL-13 were detected after 24 weeks. Renal lesions were also observed. The results showed that melatonin antagonized the increasing levels of IgM anti ssDNA and histone autoantibodies. Melatonin could also decrease the IL-6 and IL-13 production and increase the IL-2 production. Besides, melatonin could lessen the renal lesions caused by pristane. These results suggested that melatonin has a beneficial effect on pristane-induced lupus through regulating the cytokines disturbances.

Figure 1

The sera of mice in each group were collected before treatment (0), 2, 4, and 8 weeks later, and levels of IgM anti-ssDNA and Antihistone antibodies were detected by ELISA. EI was calculated according to the formula. (a) the level of IgM anti-ssDNA antibody in each group, (b) the level of IgM Antihistone antibody in each group. Data were given in mean ± SD (n = 6–8). *P < .05, **P < .01 versus sera at 0 wk, ∆P < .05, ∆∆P < .01 versus sera in model control mice.

Figure 2

All mice were sacrificed at the end of 24 weeks, and splenic lymphocytes were seeded at 1 × 10⁶ cells/well. IL-2 concentrations in splenic lymphocytes were stimulated for 48 h with 3 mg/L ConA. IL-6, and IL-13 concentrations in splenic lymphocytes were stimulated for 48 h with 12 mg/L LPS. IL-2, IL-6, and IL-13 concentrations in culture supernatants were detected by ELISA. Data were given in mean± SD (n = 4–5). **P < .01, *P < .05 versus Normal control group, ∆P < .05, ∆∆P < .01 versus Model control group.

Figure 3

The kidneys collected at the time of sacrifice were stained with H&E for histological examination. (a) Normal control group (HE × 200). (b) Model control group (HE × 200). (c) Model control group (HE × 400). (d) MT group (HE × 200).