ABSTRACT
Background: Being a highly immature organ at birth, the rat kidney is morphologically as fetal when compared with humans. Events that occur during fetal development might determine adult renal diseases
Aim of work: This study aimed to characterize the postnatal developmental changes of the kidneys in albino rats using light microscope from postnatal day [PND] 2 until PND 70. This may give references to pathologists when evaluating juvenile toxicology studies
Materials and Methods: Ten healthy pregnant albino rats were used in this study. Twenty-five of their offsprings were obtained and divided according to age into five groups of 5 pups each. Group A: studied at PND 2. Group B: studied at PND 10. Group C: studied at PND 20. Group D: studied at PND 30. Group E: studied at PND 70. Kidneys were removed, processed for light microscopic study and 5m thick paraffin sections were obtained and stained with hematoxylin and eosin stain
Results: Light microscopic examination of the renal cortex at PND 2 revealed subcapsular nephrogenic zone contained immature renal developmental stages, juxtamedullary zone contained formed glomeruli with medullary rays between the two zones. The renal cortex acquired maturation centrifugally with the superficial nephrons was the last to mature by PND 20. The papilla was the most mature region of the kidney and at PND2; it had the structural composition of the inner stripe of outer medulla. The papillary maturation involved a process of tubular elongation and increase in the interstitium until reaching adult structure by PND 20. At PND 2, the medulla was the most immature zone being formed of islets of tubular structures among abundant interstitium with high degree of undifferentiation. Its maturation involved tubular elongation and decrease of the interstitium with the outer medulla was the last to mature as late as PND 30. Consequently, the medulla remained immature for a relatively long postnatal period, in comparison to the other kidney regions
Conclusion: It was concluded that, rat kidney is immature at birth and kidney sub regions mature at different rates during postnatal development. The papilla was the first to mature [PND 20] followed by the cortex [PND 20] and finally the medulla [PND 30]
ABSTRACT
Zineb is one of the ethylene-bis-dithiocarbamate fungicides which are widely used for the plant protection especially grains, vegetables and fruits. Potential exposure to zineb can occur in workers engaged in the production and use of the fungicide, people living in agricultural areas where the compound is sprayed and people consuming polluted products. Zineb can produce toxic effects on the testes and chromosomes. This study was performed to evaluate the possible protective role of vitamin [E] against zineb-induced toxicity on the testicular structure and chromosomal pattern of adult male albino rats. Ninety six albino rats equally divided into six groups were used; the first group was used as a negative control. The second group: each rat was given l C.C. distilled water orally once daily for 3 months and the third group: each rat was given I C.C. com oil orally once daily for 3 months were used as positive control groups. The fourth group: each rat was given 1/10 LOSO of zineb which is 5 gm/Kg. body weight once daily orally for three months. The fifth group: each rat was given vitamin [E] I 00 mg/kg once daily orally for three months. The six group: each rat was given both zineb and vitamin [E] for three months. At the end of the study [after 3 months]. The tests of zineb-treated rats [group 4] showed significant histopathological alterations in the form of distorted 1>eminiferous tubules with irregular contour. The tubules were shrunken and attain different shapes and separated from each- other by wide interstitial spaces. These changes were confirmed by electron microscope that showed marked loss of spennatogenic cells, the distorted spennatids had an irregular outline and their nuclei showed densely packed chromatin material. Their cytoplasm was poor with organoids. Leydig cells appeared with irregular outlined nuclei. The rats of group 6 [zineb and vitamin E group] showed less histopathological changes when compared with group 4 [zineb group]. Moreover, chromosomal study of zineb-treated rats showed a significant increase in the frequency of structural and numerical chromosomal aberrations when compared with groups 1, 2 and 3 and group 6 [zineb and vitamin E group]. It could be concluded that chronic zineb exposure can induce testicular and chromosomal abnormalities, while simultaneous administration of vitamin [E] can ameliorate such toxic effects, indicating that vitamin [E] can play a protective role against the toxic effects of zineb on the testis and chromosomal pattern of adult male albino rats
ABSTRACT
Ammonium molybdate is an essential trace element in plants and animals as a cofactor for enzymes and also, it is an environmental pollutant. Sixty adult male albino rats were used to investigate the adverse effects of ammonium molybdate on the bone, brain, spinal cord and chromosomes. The rats were equally divided into 3 groups. The 1[st] group was left without treatment and used as a negative control group, the 2[nd] group was daily intragastrically administered saline for 30 days and was used as a positive control group and the 3[rd] group was daily intragastrically administered ammonium molybdate in a dose of 33 mg /kg body weight [1/10 of the lethal dose fifty] for 30 days. At the end of the study ten rats from each group were sacrificed, necropsied and specimens from the bone, brain and spinal cord were collected for histopathological examination. The remaining ten rats of each group were used for studying the chromosomal pattern of bone marrow cells. Histopathological examination of the rats of the 3[rd] group [ammonium molybdate group] showed reduction in the thickness of the bone trabeculae with formation of numerous osteoid fractures and fissures of the epiphysis and necrotic osteocytes. There is also separation between the cortical bone from the periosteum and the endosteum. The bone marrow cavity contains numerous large fat cells with lacked hemopoietic activity. The brain showed congestion of meningeal and cerebral blood vessels, edema, gliosis and neuronophagia. The spinal cord showed satillitosis, gliosis in the grey matter and encephalomalacia and demyelination in the white matter. Regarding cytogenetic study of the bone marrow cells, molybdenotic rats showed a significant increase in the incidence of chromosomal aberrations as terminal chromatid deletions, chromosomal fragments and ring chromosomes when compared with the control group. It could be concluded that, ammonium molybdate is genotoxic and can produce toxic effects on the bone, brain and the spinal cord of adult male albino rats