| Abstrakt: |
The effects on brain development of cross-fostering mice at birth from essential fatty acid (EFA)-deficient to EFA-sufficient diets and vice versa were examined. Four groups of animals were studied: [C], animals reared on an EFA-sufficient diet throughout pre- and postnatal life; [D], animals reared on an EFA-deficient diet throughout pre- and postnatal life; [C → D], animals receiving an EFA-sufficient diet prenatally and cross-fostered to an EFA-deficient diet at birth; and [D → C], animals receiving an EFA-deficient diet prenatally and cross-fostered to an EFA-sufficient diet at birth. Indices of brain growth (i.e. wet weight, DNA and protein content) and myelination (brain proteolipid and galactolipid content) were measured on animals ranging in age from 0 to 9 weeks in the four experimental groups. Essentially no differences were observed in any of the brain growth or myelination parameters on pups in the [D] or [C → D] groups. In almost all cases the developmental curves of the two groups were superimposable. In contrast, the developmental curves of the [D → C] animals were not superimposable on the control curves. A pronounced time lag of almost 6 weeks was observed before their body and brain weights attained control levels. However, the brain protein and DNA levels in the [D → C] group still did not reach control values by 9 weeks. Studies on the myelination parameters indicated that brain proteolipid accumulation in animals in the [D → C] group appeared to be unaffected by prenatal EFA deficiency, but galactolipid content remained below control values throughout the course of the study. These results suggest that mice “rehabilitated” from EFA-deficient to EFA-sufficient diets at birth may possess abnormal myelin for at least 2 months during a period of rapid brain maturation. |
