Effect of melatonin and zinc on the immune response in experimental Toxoplasma retinochoroiditis.
OBJECTIVE
To investigate the possible effect of melatonin (MEL) and zinc on the immune response to Toxoplasma gondii retinochoroiditis in the rat model of infection and to establish the possible value of artificial MEL and/or zinc supplementation as adjunctive therapeutic agents in the treatment of T. gondii retinochoroiditis.


METHODS
Eighty-four Sprague-Dawley male rats were divided into 12 equal groups. All groups, except controls were infected with T. gondii parasite by intraperitoneal injection. Combinations of zinc-deficient diet, pinealectomy (Px), and artificial zinc and MEL were supplied during a 1-month period. At the end of the experiment, retinal and choroidal total lymphocytes, CD3+, CD4+, and CD8+ cell numbers were counted in histological sections.


RESULTS
The highest amount of cellular infiltration (lymphocytes, CD3+, CD4+, CD8+ cells) in the choroid and retina was detected in infected + MEL + zinc-treated rats, and the least amount of cellular infiltration was observed in Px + zinc-deficient diet-treated rats. Although single zinc or MEL supplementation had no significant impact on the cellular infiltration in the retina and choroid in Px rats, combined therapy significantly improved these responses.


CONCLUSIONS
Artificial supplementation of MEL and zinc should be considered as an adjunctive therapy to classic treatment of Toxoplasma retinochoroiditis especially in immunosuppressed and elderly patients if our data are confirmed in a clinical setting.
Avunduk
Avni Murat
AM
Department of Ophthalmology, School of Medicine, Karadeniz Technical University, Trabzon, Turkey. avunduk@ttnet.net.tr
Avunduk
Mustafa Cihat
MC
Baltaci
Abdülkerim Kasim
AK
Moğulkoç
Rasim
R
D000276:Adjuvants, Immunologic / Q000627:therapeutic use*; D000818:Animals; D000917:Antibody Formation / Q000187:drug effects; D002825:Chorioretinitis / Q000276:immunology* / Q000469:parasitology* / Q000473:pathology / Q000628:therapy; D002829:Choroid / Q000473:pathology; D004357:Drug Synergism; D008214:Lymphocytes / Q000187:drug effects / Q000473:pathology; D008297:Male; D008550:Melatonin / Q000627:therapeutic use*; D010870:Pineal Gland / Q000601:surgery; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000473:pathology; D014126:Toxoplasmosis, Ocular; D015032:Zinc / Q000627:therapeutic use*
D000276:Adjuvants, Immunologic; D015032:Zinc; D008550:Melatonin