RESUMO
Recently, plant growth hormones have been widely used in green houses and the consumptions of agriculture food products have markedly increased; however their toxicological aspects are still unclear. The aim of the present study is to illustrate the toxicities of plant growth hormones; gibberellic (GA3) and indole acetic acid (IAA) on ocular tissues of pregnant Wistar albino rats and their offsprings. Intra-gastric administration of either GA3 or IAA (100 mg/kg body weight) to mother rats were carried out for one month prior to conception as well as throughout gestation period (n=20). The control received saline-free organochemical compounds (n=10). At parturition, mother rats and their offsprings were sacrificed by light anesthesia, and their ocular regions were separated and investigated for light and transmission electron microscopy, immunochemical staining of Caspase-3, Bcl-2 and p53 and assessments of antioxidant enzymes and DNA fragmentation. Maternal administration of either GA3 or IAA was found to develop cataractous lenses to about 6% (3/20) in GA3-treatment and 4% (2/20) in IAA-treatment. The applied organochemical compounds developed retinopathy in mother rats and their offsprings. These were characterized by apparent damage of ganglion and nuclear cells. In mothers, the photoreceptor’s outer segment showed spotty dissolution of their stacked membranes while in offsprings, there was still lack of differentiation. The retinal tissue showed discrete positive immunostaining foci with P53, Pcl2 and caspase-3, especially in ganglion and nuclear cells compared with control. The antioxidant enzymes' catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR) and peroxidase (GPx) showed apparent depletion and vice versa for malondialdhyde (MDA) and hydrogen peroxide (H2O2), the markers of cell death. DNA fragmentation was markedly detected. Finally, it was concluded that maternal administration of GA3 and IAA led to the development of retinopathy and development of cataractous lenses parallel to the increase of immunostaining of caspase-3, Pcl2 and P53 and decrease of the endogenous antioxidant system and increase of DNA damage.
RESUMO
Aims: To correlate the age-related structural changes in lens with its contents of amino acids and minerals involved in its functional activity (sodium, calcium, magnesium and copper). Study Design: Experimental study. Place and Duration of Study: Department of Zoology, Faculty of Science, Mansoura University, Egypt, between June 2009 and July 2011. Methodology: One hundred male and female albino rats of the Wistar strain (Rattus norvegicus) aging 1, 6, 18, 30 & 42 months were used during experimentation. At the mentioned ages, the animals were sacrificed by diethyl ether and ocular regions were dissected and lens separated. Amino acids content were determined in both lenses of five individuals. In the other five individuals, unilateral ectomized lenses were subjected for chemical determination of calcium, sodium, cupper and magnesium. The rest lenses on the other side were fixed in 10% phosphate buffered formalin followed by 2.5% glutaraldhyde for scanning electron microscopic investigation. Statistically analysis was carried out by the help of SPSS software. Results: The estimated amino acids were altered in both sexes with advancement of aging. The lens amino acids; taurine, prolline, serine, threonine, methionine, lysine and arginine were markedly increased during aging comparing with apparent depletion of asparate, valine and methionine. The alterations in amino acid contents were parallel with increased accumulation of calcium, sodium and cupper and a depletion of magnesium content. Scanning Electron Microscopic (SEM) observations exhibited sequences of changes of the structures of lens fibers and their pattern of attachments during the advancement of aging. In the advanced aged group, the lens fibers become fragile and widely separated as a result of loosely attached of the interfibrillar junctions of the ball and socket especially at 30 & 42 month old rats. Conclusion: Aging led to alterations of lens fibers at ultrastructural levels associated with diversity of changes in their amino acids contents parallel with increase accumulation of sodium, calcium and cupper and a decrease of magnesium content. The observed findings may be attributed to the increase of advanced glycation end products initiated oxidative stress, impairing lens structure and function.