Heat stress and antioxidant enzyme activity in bubaline (Bubalus bubalis) oocytes during in vitro maturation

Abstract

In vitro environments like heat stress usually increase the production of reactive oxygen species in bubaline oocytes which have been implicated as one of the major causes for reduced developmental competence. Oocytes during meiotic maturation are sensitive to oxidative stress, and heat stress accelerates cellular metabolism, resulting in the higher production of free radicals. Therefore, the aim of present work was to assess the impact of heat stress during meiotic maturation on bubaline cumulus-oocyte complexes (COC), denuded oocytes (DO), and cumulus cell mass in terms of their oxidative status. Accordingly, for control group, COC were matured at 38.5 °C for complete 24 h of meiotic maturation and heat stress of 40.5 and 41.5 °C was applied to COC during the first 12 h of maturation and then moved to 38.5 °C for rest of the 12 h. In another group, COC after maturation were denuded from the surrounding cumulus cells by manual pipetting. Results indicated that the production of reactive oxygen species (ROS), lipid peroxides, and nitric oxide (NO) was significantly (P < 0.05) higher in the oocytes subjected to heat stress (40.5 and 41.5 °C) during meiotic maturation compared to the oocytes matured under standard in vitro culture conditions (38.5 °C). Also, the antioxidant enzymatic activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase were significantly (P < 0.05) increased in all the treatment groups compared to the control group. Therefore, the present study clearly establishes that heat stress ensues oxidative stress in bubaline oocytes which triggers the induction of antioxidant enzymatic defense system for scavenging the ROS.

Nutritional and metabolic stressors on ovine oocyte development and granulosa cell functions in vitro

“…The determination of ROS in matured oocyte and granulosa cells was as described earlier (Waiz et al 2016). For measuring the concentration of ROS produced, oocytes (n = 20 in each treatment) and granulosa cells (1 × 10 5 in each treatment) were sonicated over ice.…”

Elevation of MPF and MAPK gene expression, GSH content and mitochondrial distribution quality induced by melatonin promotes porcine oocyte maturation and development in vitro

“…It involves the immature oocyte extraction from the ovaries, and it's in vitro culture until it has reached the maturation stage (Hoelker et al, 2017;Lonergan & Fair, 2016). During in vitro culture and maturation, oocytes generate a high amount of Reactive Oxygen Species (ROS) as a result of mechanical treatment, air, light, and other factors (Waiz et al, 2016). Although the physiological dose of ROS is favorable for the oocyte maturation and development, excessive ROS leads to adverse effects due to the DNA damage, mitochondrial dysfunction, lipid peroxidation, abnormal protein modification, and so on (Rajani et al, 2012).…”

C-phycocyanin protects against low fertility by inhibiting reactive oxygen species in aging mice

“…ROS negatively affect processes from oocyte maturation to fertilization, embryo development, and pregnancy, and they are associated with the age-related decline in reproduction [ 3 , 11 , 12 ]. Previous reports demonstrated that ROS accumulation in cells can lead to cytoskeletal derangement [ 13 ], shortened telomeres [ 14 ], impaired telomerase activity [ 15 ], antioxidant system dysfunction [ 16 , 17 ], disturbances of ATP levels [ 18 ] and mitochondrial distribution [ 19 ], and cell apoptosis [ 20 ].…”