Long-term effects of maternal exposure to surgical stress at the earliest stage of pregnancy on blood pressure and behavior in offspring of OXYS rats

Abstract

The use of some assisted reproductive technologies, in particular, embryo transfer, may cause various physiological and behavioral changes in the offspring. The purpose of our study was to study the effects of surgery (which is used for embryo transfer) done with pregnant dams on the weight, blood pressure and behavior in the open field and elevated plus­maze tests in adult offspring. Thus, long­term effects on the offspring after maternal exposure to surgical stress given to dams at the 4th day of pregnancy were studied in OXYS rats. OXYS females were mated in estrus with fertile males of the same strain. 96 hours after spermatozoa were found in vaginal smears the surgery (sham operation, imitating embryo transfer) was performed. Body weight (BW), systolic (SAP) and diastolic (DAP) arterial pressure as well as behavior in open field (OF) and elevated plus maze (EPM) tests were studied in the offspring of females exposed to surgical treatment during pregnancy (OXYS­PS) at the age of 3 mo. Untreated offspring of OXYS rats were used as controls. BW in naturally born OXYS rats did not differ from those of the OXYS­PS group. OXYS and OXYS­PS rats exhibited higher SAP (more than 150 mm Hg) and DAP; it is noteworthy that both SAP and DAP were higher in the OXYS­PS group than in the control group. The time spent in the center of arena, the area studied, the time and number of rearing were decreased in OXYS­PS rats in the OF test as compared to the OXYS controls. Moreover, OXYS­PS rats were characterized by the absence of grooming in the OF test. As was demonstrated by the EPM test, the duration and numbers of peeking out from closed arms were decreased in the OXYS­PS rats as compared to the OXYS controls. Thus, OXYS dams’ exposure to surgical stress at their early pregnancy led to such effects in the offspring as elevated SAP and DAP, decreased overall activity and increased anxiety.