تاثیر مقدار ویتامین D3 و اینترفرون گاما بر تکثیر تاکی زوییت های توکسو پلاسما گوندیی و تولید نیتریک اکساید در ماکروفاژهای صفاقی موش Balb/C

Background and purpose : Toxoplasma gondii is an obligate interacelullar parasite that infect a wide variety of nucleated cells in its intermediate hosts. Tachyzoites of Toxoplasma gondii in able to multiply in mouse macrophages. Inducing synthesis of nitric oxide (NO) by macrophages is an important mechanism of the host defense against interacelullar infection in mice. The 1.25 dihydroxy vitamin D3 is a potent modulator of immune system and may be beneficial in the treatment of some diseases. Recent evidence suggests that, 1,25 dihydroxy vitamin D3 may increase production of nitric oxide. Otherwise 1,25 dihydroxy vitamin D3 acts to suppress the Th1 immune response that effect on antigen presenting cell and increases production of Th2 cell. The aim of present study is to determine effective concentration of 1,25 dihydroxy vitamin D3 for stimulation of nitric oxide production. The effect of 1,25 dihydroxy vitamin D3 on multiplication of Toxoplasma gondii in macrophage of Balb/c mice in vivo and in vitro were also studied. Materials and methods :Mice were injected with different doses of 1,25 dihydroxy vitamin D3 and/or Toxoplasma gondii interpretoneally. Then infected macrophages were cultured in RPMI-1640. Culture supernatants were collected for nitric oxide assay following 18 hours, then every 24 hours intervally. Nitric oxide was measured by Griess method. Infection levels were assessed microscopically by counting the numbers of tachyzoites in macrophages. Results :This results indicated that there is a decrease in the number of T.gondii in macrophages following treatment with 1,25 dihydroxy vitamin D3 dose dependent (P<0.05). In addition, injection of 1,25 dihydroxy vitamin D3 plus INFγ in medium culture inhibited the multiplication of T.gondii. High level of production of nitric oxide may relate to dose of 1,25 dihydroxy vitamin D3 plus INFγ. Conclusion: In the dose of 1000 microgram of vitamin D3 the highest killing effect of macrophages were demonstrated.