Effectiveness of iron repletion in the diet for the optic nerve development of anaemic rats.
OBJECTIVE
To compare the process of myelination in the developing optic nerve (ON) of anaemic rats with the subsequent recovery after being fed an iron-recovery diet.


METHODS
In this study, the morphometrical parameters in the ON were assessed by electron microscopy in Wistar rats that were on an iron-deficient diet for 32 days or for 21 days followed by 10 days on an iron-recovery diet. Qualitative and quantitative analyses were performed using representative electron ultramicrographs. Data were analysed by one-way analysis of variance (ANOVA). When differences were detected, comparisons were made using Tukey's post hoc test (P<0.05 was considered to be significant).


RESULTS
Qualitative analysis of the ONs in anaemic and recovered animals showed a higher rate of deformed axons and increased lamellar separation in the myelin sheath when compared with the respective control group. The ON of the anaemic group showed a reduced mean density of myelinated fibres when compared with the control group. The fibre area ratio, axon area ratio, and myelin area ratio of large axons/small axons in the ONs of the control group showed the highest values for the myelin areas, axon areas, and total fibre areas. The control group showed a significantly higher myelin sheath thickness when compared with the anaemic and recovered groups.


CONCLUSIONS
Our data indicate that iron is necessary for maintenance of the ON cell structure, and that morphological damage from iron deficiency is not easily reverted by iron repletion.
DeMaman
A S
AS
Laboratório de Neuroanatomia, Faculdade de Medicina de Ribeirão Preto, Departamento de Cirurgia e Anatomia, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
Melo
P
P
Homem
J M
JM
Tavares
M A
MA
Lachat
J-J
JJ
D000704:Analysis of Variance; D018798:Anemia, Iron-Deficiency / Q000188:drug therapy* / Q000473:pathology; D000818:Animals; D019587:Dietary Supplements; D004195:Disease Models, Animal; D007501:Iron / Q000008:administration & dosage*; D000090463:Iron Deficiencies; D008854:Microscopy, Electron; D009186:Myelin Sheath / Q000187:drug effects* / Q000473:pathology / Q000502:physiology; D018696:Neuroprotective Agents / Q000008:administration & dosage*; D009900:Optic Nerve / Q000473:pathology / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
D018696:Neuroprotective Agents; D007501:Iron