Effects of Hoechst 33342 staining and ultraviolet irradiation on mitochondrial distribution and DNA copy number in porcine oocytes and preimplantation embryos.
Hoechst 33342 (H342), in combination with ultraviolet (UV) irradiation, is frequently used to aid or confirm the enucleation of porcine oocytes in somatic cell nuclear transfer programs. The exposure of oocytes to H342 and UV irradiation has a deleterious effect on the development of in vitro-fertilized porcine oocytes, with increasing exposure to UV irradiation (up to 30 sec) having more drastic effects. It has been hypothesized that this decrease in embryonic development could be due to damage to the mitochondrial DNA (mtDNA). To investigate this hypothesis, we analyzed the mitochondrial distribution and DNA copy number of in vitro-matured porcine oocytes exposed to H342/UV and the subsequent embryonic development compared with the mitochondrial distribution and DNA copy number of in vivo-derived oocytes and embryos. Using quantitative, real-time polymerase chain reaction (qPCR) protocols to analyze mtDNA and confocal laser scanning microscopy with MitoTracker Deep Red to determine mitochondrial distribution, we demonstrated that the simultaneous exposure of in vitro-matured porcine oocytes to H342 staining and UV irradiation is associated with reduced oocyte developmental competence and abnormal mitochondrial distribution in the resulting cleaved embryos. In addition, 2- to 4-cell embryos derived from oocytes exposed to H342/UV showed a significant decrease in mtDNA copy number. These results should be considered when H342/UV procedure is used during nuclear transfer in recipient porcine oocytes.
Department of Animal Medicine and Surgery, Regional Campus of International Excellence, University of Murcia, Murcia, Spain. mariagil@um.es
Maria Antonia
MA
Gil
Carolina
C
Maside
Cristina
C
Cuello
Inmaculada
I
Parrilla
Juan Maria
JM
Vazquez
Jordi
J
Roca
Emilio Arsenio
EA
Martinez
D000818:Animals; D001562:Benzimidazoles / Q000009:adverse effects* / Q000494:pharmacology; D001755:Blastocyst / Q000378:metabolism* / Q000473:pathology; D056915:DNA Copy Number Variations / Q000187:drug effects / Q000528:radiation effects; D004272:DNA, Mitochondrial / Q000378:metabolism*; D005260:Female; D005456:Fluorescent Dyes / Q000009:adverse effects* / Q000494:pharmacology; D008928:Mitochondria / Q000378:metabolism* / Q000473:pathology; D009865:Oocytes / Q000378:metabolism* / Q000473:pathology; D060888:Real-Time Polymerase Chain Reaction; D013552:Swine; D013997:Time Factors; D014466:Ultraviolet Rays / Q000009:adverse effects*
D001562:Benzimidazoles; D004272:DNA, Mitochondrial; D005456:Fluorescent Dyes; C017807:bisbenzimide ethoxide trihydrochloride