Introducing an optimized method for purifying Toxoplasma gondii genomic DNA from rat brain to increase diagnosis efficiency of Toxoplasma infection

Extraction of Toxoplasma gondii genomic DNA from rat brain is challenging due to low level of contamination and high fat content. Quantitative real-time polymerase chain reaction (RT-qPCR) is associated with false negative results despite detecting small amounts of the gene. By changing method of DNA extraction, we could decrease number of false negative results.

Brains of eleven male Wistar rats infected with Tehran strain of Toxoplasma parasite (with 8 weeks of parasite infection) and three uninfected rats were isolated. The whole brain was used to purify DNA instead of 20 mg brain in the conventional method. Amount of protein kinase was doubled and the incubation period increased to 6 times. Then DNA of the samples was measured by RT-qPCR.

Only three of the eleven infected rats were infection positive by the conventional method, while nine mice were positive by the optimizing method.
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