<i>In vivo</i> tetracycline treatment leads to apoptosis in adult worm reproductive tissues.

<p>(A) Schematic drawing of one female reproductive tract, representing the approximate localization of the different sections observed in the TUNEL assay. TUNEL experiments showing the DNA (PI in red) and incorporated fluorescein-dUTP (green), in samples from non-treated (B, D, F, H) or tetracycline-treated (C, E, G, I) <i>B. malayi</i> females. Mitotic proliferation zone in the distal ovary (B, C). Arrowheads indicate mitotic nuclei, arrows point to somatic gonad nuclei. (D) Uterus filled with elongating embryos. (E) Fertilization area in the distal uterus in the top left corner, and proximal uterus filled (in diagonal) with developing embryos. (F, G) Single developing embryos. (H, I) Intrauterine microfilariae extracted from proximal uteri. (J) TUNEL quantification. For each un-treated (NT) or tetracycline-treated (TET) sample, TUNEL-positive nuclei or embryos were counted and expressed as a percentage of total nuclei or embryos (based on DNA staining with PI). For the embryonic count (“embryos NT”, “embryos TET”), embryos with a number of TUNEL positive nuclei equal or less than 2 positive nuclei were considered as negative embryos. All the intrauterine microfilariae found TUNEL-positive in the TET sample had every nuclei TUNEL-positive (I). Scale bar = 15 µm.