Blue light-emitting diode phototherapy reduces cerebral parasitic load and inflammation in murine congenital toxoplasmosis model

The search for effective therapies to eradicate Toxoplasma gondii, the causative agent of toxoplasmosis, has spanned decades with limited success. Current drugs, including sulfadiazine, spiramycin, and pyrimethamine, face limitations such as parasite resistance, high cellular toxicity, inconsistent efficacy in the acute phase of disease, and the lack of effect in the chronic phase. This study evaluates an innovative adjunctive approach using light-emitting diode phototherapy (BLP) to control T. gondii acute infection during pregnancy. For that, pregnant female Swiss mice (8-9 weeks) were orally infected with 10 cysts of the ME49 strain of T. gondii and exposed to BLP (460 nm, 7 μW/cm2) or conventional white light for 12 h/day over 12 days. After the treatment period, the females were euthanized, and the fetuses, placentas, liver, spleen, maternal brain, and blood were collected for analysis. BLP reduced parasitic load in brain tissue and modulated tissue-specific immune responses, with increased IL-10 in the brain and fetal tissues, elevated CCL2 in liver parenchyma and fetal tissues, and induction of TNF in fetal samples. Serum ferritin and oxidative stress, thiobarbituric acid-reactive substances (TBARS), and superoxide dismutase (SOD) increased in infected mice exposed to BLP, while catalase (CAT) remained unchanged. These findings suggest that BLP exerts both immunomodulatory effects on the infected host and cytotoxicity against T. gondii, supporting its potential as an adjunctive approach for etiological treatment in congenital toxoplasmosis.