The Importance of Checking Leishmania Promastigotes Viability in the Proteomics Analysis of Secretions.

OBJECTIVE: The aim of the present study was to compare the efficacy of checking the viability of Leishmania promastigote by flow cytometry using propidium iodide (PI) and microscopic method using trypan blue (TB) before proteomics analysis of the secretions.

METHODS: The promastigotes (6×109) of Leishmania infantum in the exponential growth phase were transferred to serum-free media. Then, the viability of promastigotes was checked and compared with flow cytometry and microscopic method at 0, 2, 3, 4, 5, and 72 h.

RESULTS: Flow cytometry did not show many dead cells at 0 to 4 h, and the viability was approximately 98%. The percentage of the dead promastigotes increased to 8% at 5 h and 17% at 72 h. Meanwhile, the microscopic method using TB did not show any dead cell after 4 and 72 h, and the viability was 100%.

CONCLUSION: The present study confirms the importance of flow cytometry using PI in checking the viability of Leishmania promastigotes, especially before the proteomics analysis of the secretions. It also shows that flow cytometry using PI is more sensitive than microscopic method using TB.