Cathepsins (CTS) are lysosomal cysteine proteinases, of which elevated transcript content is attributed to the reduced quality of oocytes. The aim of this study was to investigate whether transcript content of three CTS genes in cumulus cells (CC) may be related to oocyte quality. The relationships between mRNA content of CTS genes in CC, the fatty acids profile in follicular fluid (FF) and selected quality traits of the corresponding oocyte (COC morphology, follicle diameter, mtDNA copy number) were investigated. Although an increased RA of the CTSB and the CTSK genes was accompanied by inferior COC morphology, it was also correlated with a higher mtDNA copy number in the oocyte and an increased content of C18.3n3 and n3 in FF. The last two traits were attributed to better quality oocytes, which contrasts with the high RA of the CTS genes. In conclusion, elevated transcript levels of CTS genes within CC are of limited value as an indicator of reduced quality in bovine oocytes. We suggest that the possible reason for the ambiguity of the obtained data could be the origin of cumulus cells within the COC, which may prove to be crucial for this type of studies.This article is published as Warzych E., Cieslak A., Wolc A., Lechniak D. 2016. Cathepsins mRNA level in bovine cumulus cells fail to be a good marker for oocyte quality. Animal Science Papers and Reports 34:339-349.</p
