[Study on effect of lead exposure to blood lead level and hearing in young offspring through gestation-rat].

OBJECTIVE: To study the effect of lead exposure to the blood lead level and the hearing in young offspring through gestation-rat. METHOD: Experiments were carried out on 42 Wistar rats, half female and half male, randomly divided into five couple groups (A, B, C, D, E). The group A, as a normal control group, was fed with a standard diet. The group B, C, D and E were fed with a standard diet, additionally with 0.03%, 0.090%, 0.27% and 0.81% lead acetate added respectively, and then fed with standard diet after birth. DPOAE, ABR and blood lead measurement were conducted on the parents rats and the neonatal offspring rats at first week and at the third week respectively. RESULT: The blood lead level of neonatal rat reported positively related with that of the parent rats (r = 0. 5817). DPOAE test result: Both parent rats and neonatal rats presented a normal cochlea feedback curve. ABR test result: The period of the group D showed a significant difference from that of the normal control group A. Reaction threshold (dBpeSPL) of the neonatal rat group cl (at the first week) and group c3 (at the third week) showed a notable difference from that of the normal control group al and a3 (c >a). CONCLUSION: The blood lead level of a fetus rat is related with the exposure degree to lead during the pregnant period of mother rat. Low level lead exposure inside uterus during pregnant period will result easily in damage on the hearing nerve center segment and hearing conduct of a fetus rat for they are very sensitive.

Lead exposure through gestation-only caused long-term learning/memory deficits in young adult offspring.

Numerous observations in clinical and preclinical studies indicate that the developing brain is particular sensitive to lead (Pb)'s pernicious effects. However, the effect of gestation-only Pb exposure on cognitive functions at maturation has not been studied. We investigated the potential effects of three levels of Pb exposure (low, middle, and high Pb: 0.03%, 0.09%, and 0.27% of lead acetate-containing diets) at the gestational period on the spatial memory of young adult offspring by Morris water maze spatial learning and fixed location/visible platform tasks. Our results revealed that three levels of Pb exposure significantly impaired memory retrieval in male offspring, but only female offspring at low levels of Pb exposure showed impairment of memory retrieval. These impairments were not due to the gross disturbances in motor performance and in vision because these animals performed the fixed location/visible platform task as well as controls, indicating that the specific aspects of spatial learning/memory were impaired. These results suggest that exposure to Pb during the gestational period is sufficient to cause long-term learning/memory deficits in young adult offspring.