Superoxide dismutase and glutathione peroxidase activities in bovine placenta : spectrophotometric and electrophoretic analysis

Reactive oxygen species are unavoidable products of metabolism and in excess they can be dangerous for tissues and cells. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), among others, protect tissues and cells against reactive oxygen species. The aim of the study was the description of SOD and GSH-Px from bovine placenta by use of spectrophotometric and electrophoretic analysis according to time and mode of delivery. The placental samples were obtained immediately after spontaneous delivery at term as well as preterm and term caesarian section. Animals were divided into 3 groups : A-preterm caesarian section, B-term caesarian section, C-term spontaneous delivery. The activity of examined enzymes was measured spectrophotometrically in maternal and fetal part of placenta and expressed in nkat/g prot for GSH-Px and in Units/g prot for SOD. Results of zymografic electrophoresis were expressed in optical density of bands. SOD activity was significantly the highest in preterm group (maternal and fetal placenta : 7.27 ± 0.69 U/g, 8.85 ± 0.95 U/g respectively). In term groups the enzyme activity significantly decreased (B maternal and fetal placenta : 3.93 ± 0.22 U/g, 2.79 ± 0.18 U/g respectively and C maternal and fetal placenta : 4.48 ± 0.59 U/g and 2.91 ± 0.44 U/g respectively). The molecular weights of enzymes determined by electrophoresis were 35 kDa and 85 kDa for SOD and GSH-Px respectively. GSH-Px activity increased towards parturition and was significantly higher in fetal than in maternal part of placenta in all groups examined (A 114.32 ± 9.15 vs 54.18 ± 6.81 ; B 181.44 ± 12.65 vs 117.39 ± 7.28 ; C 135.11 ± 14.65 vs 87.15 ± 10.25nkat/g). In conclusion, the activity of SOD and GSH-Px in bovine placenta depended on time and mode of delivery.