title: Expression pattern of glucose metabolism genes correlate with development rate of buffalo oocytes and embryos in vitro under low oxygen condition.
abstract: OBJECTIVE
  This study evaluates the effect of low oxygen conditions (5 Vs 20%) on buffalo embryo development. Expression patterns of key glucose metabolism genes (HK, PFK, LDH, PDH, G6PDH and Glut1) were assessed in buffalo oocytes and embryos cultured at 5 and 20% oxygen and correlated with development rate.
  
  
  METHODS
  Maturation rate was observed by determining MII stages by Aceto-orcein method and blastocyst formation was observed at 7 day post insemination (dpi). Expression levels of genes were determined by real time PCR in oocytes / embryos at 5 and 20% O2.
  
  
  RESULTS
  Oocyte maturation and blastocyst formation rates were significantly higher at 5% O2 as compared to 20% O2 (P < 0.05). The expression pattern of glycolytic genes (HK, PFK and G6PDH) indicated that oocytes and embryos under 5% O2 tend to follow anaerobic glycolysis and pentose phosphate pathways to support optimum embryo development. Under 20% O2, oocytes and embryos had high expression of PDH indicating higher oxidative phosphorylation. Further, less G6PDH expression at 20% O2 was indicative of lower pentose phosphate activity. Higher expression of LDH was observed in oocytes and embryos under 20% O2 indicating sub-optimal culture conditions. High Glut1 activity was observed in the oocytes / embryos at 5% O2, indicative of high glucose uptake correlating with high expression of glycolytic genes.
  
  
  CONCLUSIONS
  The expression patterns of glucose metabolism genes could be a valuable indicator of the development potential of oocytes and embryos. The study indicates the importance of reduced oxygen conditions for production of good quality embryos.
authors.affiliation: Animal Genomics Lab, ABTC, NDRI, Karnal, 132001, India, meparveen@gmail.com.
authors.forename: Parveen
authors.initials: P
authors.lastname: Kumar
authors.forename: Arpana
authors.initials: A
authors.lastname: Verma
authors.forename: Manish
authors.initials: M
authors.lastname: Kumar
authors.forename: Sachinandan
authors.initials: S
authors.lastname: De
authors.forename: Rakesh
authors.initials: R
authors.lastname: Kumar
authors.forename: Tirtha Kumar
authors.initials: TK
authors.lastname: Datta
mesh_terms: D000818:Animals; D002020:Buffaloes; D047108:Embryonic Development / Q000235:genetics*; D005260:Female; D005307:Fertilization in Vitro; D018507:Gene Expression Regulation, Developmental; D005947:Glucose / Q000235:genetics / Q000378:metabolism; D051272:Glucose Transporter Type 1 / Q000096:biosynthesis; D005954:Glucosephosphate Dehydrogenase / Q000096:biosynthesis; D006593:Hexokinase / Q000096:biosynthesis; D006801:Humans; D059471:In Vitro Oocyte Maturation Techniques; D007527:Isoenzymes / Q000096:biosynthesis; D007770:L-Lactate Dehydrogenase / Q000096:biosynthesis; D009865:Oocytes / Q000254:growth & development* / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D025221:Phosphofructokinases / Q000096:biosynthesis; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase
chemical_list: D051272:Glucose Transporter Type 1; D007527:Isoenzymes; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D007770:L-Lactate Dehydrogenase; C409667:lactate dehydrogenase 1; D005954:Glucosephosphate Dehydrogenase; D025221:Phosphofructokinases; D006593:Hexokinase; D017346:Protein Serine-Threonine Kinases; D005947:Glucose; D010100:Oxygen