The Effect of Prenatal and Postnatal Administration of Manganese Chloride on the Developing Caudate Nucleus of the Corpus Striatum in Male Albino Rats and the Possible Beneficial Role of Vitamin E Supplementation: A Histological and Immunohistochemical study

Abstract

Background: Although low levels of manganese (Mn) intake are necessary for human health but may also be toxic at high concentrations. Infants are subjected to risk of elevated Mn exposure from soy-based infant formulas and contaminated well-water which contain Mn at high levels. Young children are susceptible to be exposed to an elevated Mn levels because the developing brain is vulnerable to the chemical insult, as well as an increased absorption and retention of ingested Mn in comparison to the adults. Vitamin E is an antioxidant and is protectective to the biological membranes from oxidative stress. Aim of work:To investigate the effect of adminstration of manganese chloride (MnCL2) during pregnancy and lactation on the postnatal development of the caudate nucleus of the rat corpus striatum and to evaluate the role of vitamin E. Also, this work aimed to detect the effect of MnCL2 withdrawal.. Material and Methods: Forty-pregnant female albino rats were divided into two equal groups (20 rats each): group I (control) and group II (MnCl2-treated). Litters of the control dams were sacrificed at the age of one day (group Ia), 10 days (group Ib), 20 days (group Ic) and 2 months (group Id). MnCl2-treated dams received MnCl2 at a dose of 50 mg /kg b.w. orally daily throughout conception till 20 th day postnatally. Half of their male litters were sacrificed at the age of one day (group IIa), 10 days (group IIb) and 20 days (group IIc). The other half was sudivided at the age of 20 days into 3 equal groups: group IId received the same dose of MnCl2 till the age of 2 months, group IIe received vitamin E at a dose of 48 mg/kg b.w. orally daily till the age of 2 months concomitantly with MnCl2 and group IIf received distilled water orally daily till the age of 2 months. Animals in the previous three groups were sacrificed at the age of 2 months. Brains were processed to be studied using Einarson's gallocyanin stain, H&E, transmission electron microscopy and immunohistochemical study for glial fibrillary acidic protein (GFAP). Results: As regard the postnatal development of the caudate nucleus, there was a gradual increase in the amount of Nissl's granules and the size of the neuronal nuclei with the presence of an apparent decrease in neuronal density. A gradual increase in the density of GFAP positive cells was noticed. Maternal MnCl2 administration affected the development of the caudate of the offsprings at the different ages studied. Many cells revealed degenerative changes in the form of darkly stained pyknotic or irregular rarified nuclei and vacuolated cytoplasm. There was progressive reduction in the amount of Nissl's granules. More abundant GFAP positive cells were noticed comparable to those in the control ages. On electron microscopic study, there were dark degenerated cells and deformed myelin sheath with splitting and fragmentation of their lamellae. Swollen mitochondria with disrupted cristae were noticed in the cytoplasm of many cells. These histological and immunohistochemical changes were found to be corre...