Malini Laloraya

Changes in the levels of superoxide anion radical and superoxide dismutase during the estrous cycle of Rattusnorvegicus and induction of superoxide dismutase in rat ovary by lutropin

Superoxide dismutase, which has been shown to be present in a number of tissues, exhibits cyclic changes during the reproductive cycle of rats. An inverse correlation is seen between the levels of superoxide dismutase and superoxide radical. In immature, pseudopregnant rats, primed with human Chorionic Gonadotropin, lutropin seemed to induce ovarian superoxide dismutase, which could be blocked significantly by the introduction of anti-LH serum. These results point out the specific induction of superoxide dismutase by lutropin. It is reasonable to postulate that during luteal functioning, luteinizing hormone induces superoxide dismutase which in turn seems to play a central role generating hydrogen peroxide from superoxide anion radicals. Hydrogen peroxide, thus formed, drives the peroxidase-ascorbate system, responsible for production of progesterone.

Profiling of E-cadherin, β-catenin and Ca2+ in embryo–uterine interactions at implantation

Establishment of early pregnancy is promoted by a complex network of signalling molecules that mediate cell‐to‐cell and cell‐to‐extracellular matrix communications between the receptive endometrium and the invasive trophectoderm. In this study, we have attempted to evaluate the expression profiles of cadherin and catenin during embryo implantation in the mouse. Western blotting studies along with immunocytochemical analysis revealed that E‐cadherin is expressed rather ubiquitously in the uterine epithelial cells, distinct enrichment is observed on the apical membrane in the endometrium of peri‐implantation uterus specifically at the implantation sites and not at the inter‐implanation sites. β‐Catenin also is upregulated and is specifically restricted to apical membrane of epithelial cells of implantation sites. Progesterone induced expression of E‐cadherin and 17β‐estradiol regulated the expression of catenin in implantation‐delayed uteri. Interestingly, estradiol imparted negative modulation on cadherin expression when co‐administered with progesterone. On the contrary, trophoblast exhibits a striking down regulation of cadherin, catenin and Ca2+ at peri implanting stage. These observations suggest that the trophoblasts exhibited an invasive phenotype while the endometrial epithelium displayed an adhesive phenotype during the window of implantation. Thus, embryo implantation presents an instance where two interacting surfaces showed mutually complementing interaction phenotypes.

A possible role of superoxide anion radical in the process of blastocyst implantation in Musmusculus

Superoxide anion radical and superoxide dismutase, the enzyme responsible for dismutating it, are both present in the ovary and uterus of Mus musculus during early pregnancy. The detectable, stable levels of superoxide radical and the constant high levels of superoxide dismutase in the ovary during early pregnancy suggests that these may be involved in the regulation of extended luteal steroidogenesis for the maintenance of pregnancy. An inverse correlation between the levels of superoxide anion radical and superoxide dismutase in the uterus is shown. The high levels of superoxide anion radical in the uterus on the early morning of Day 5 of pregnancy point towards a probable role for this radical in the act of implantation and in mediating the increased vascular permeability at the initiation of implantation.

Effect of estradiol and selected antiestrogens on pro- and antioxidant pathways in mammalian uterus

In this study, we examined the effect of 17 beta-estradiol and selected antiestrogens on uterine NADPH-oxidase activity, superoxide dismutase (SOD) activity, hydride (H.-), dienyl radical and O2 -radical generation, and membrane fluidity. NADPH oxidase activity was positively modulated in estradiol-treated animals and negatively regulated in animals that received injections of AF-45, RU-39411, tamoxifen, or ICI-182780. The SOD activity was markedly reduced in estradiol-treated animals when compared with the control animals. A positive modulation of SOD activity was observed upon treatment with AF45, RU39411, tamoxifen, and ICI 182780, though the potency varied among the individual test compounds. We observed detectable H(.-)-radical generation as evidenced from MNP H.- adduct formation in the uterine cell preparations from untreated control animals. Estradiol produced a tremendous augmentation in the superoxide radical profiles in uterine cell preparations compared to the control levels. All the other compounds that were tested significantly lowered the superoxide levels in the test set-up. AF-45, RU-39411, tamoxifen, and ICI-182780 induced varying orders of suppression of H(.-)-radical generation in the test subjects. There was a significant enhancement in membrane fluidity, hydride radical levels, and dienyl radical generation in the estradiol-treated group. All the antiestrogens did not exhibit a similar action on these parameters. RU-39411 exhibited antiestrogen-like activity in modulating hydride levels and membrane fluidity, whereas it stimulated dienyl radical generation. Thus our tests showed that the selected antiestrogens failed to show estrogen-like activity in these assays. It appears that estradiol exerts feedback control over pro- and antioxidant pathways and that markers of oxidative status could be used as a measure to evaluate the antiestrogenic activity of estradiol agonists/antagonists.

Superoxide radical level and superoxide dismutase activity changes in maturing mammalian spermatozoa

Summary. Mammalian spermatozoa, which like other living cells are susceptible to oxygen toxicity, generate increasing quantities of superoxide radical as epididymal maturation proceeds. This is associated with a concomitant reduction in the activity of superoxide dismutase. A possible involvement of superoxide radicals in bringing about some of the reported oxidative changes occuring during epididymal maturation of mammalian spermatozoa is discussed. It is suggested that superoxide radical may be involved in regulating membrane changes accompanying sperm maturation.

Identification of a Soluble NADPH Oxidoreductase (BmNOX) with Antiviral Activites in the Gut Juice of Bombyx mori

Silkworms show high variability in silk quality and disease resistance. Attempts are on to combine the disease tolerance of multivoltine races and the silk quality of bivoltine races to generate new races with desirable phenotypic traits. We report the identification of a 26.5-kDa protein that is overexpressed in the gut juice of disease-resistant multivoltine races and that has anti-BmNPV activity. We have characterized this protein as a soluble NADH-oxidoreductase-like protein (BmNOX). Treatment of live BmNPV particles with BmNOX inhibited the capability of the viral particles to infect BmN cells in vitro.

Fluidity of the phospholipid bilayer of the endometrium at the time of implantation of the blastocyst — A spin label study

The endometrial phospholipid bilayer is shown to be in a highly fluid and polar state at the time of implantation in Mus musculus as evidenced from a spin label study using the stearic acid spin label, 5-doxyl stearate. The positive correlation observed between the superoxide anion radical levels and the fluidity and polarity state of the endometrial cells points towards the possibility of the mediation of this condition of unsaturation of fatty acids to be an act of the superoxide anion radical.

Superoxide dismutase as a regulatory switch in mammalian testicular steroidogenesis

The delta 4-pathway of testosterone biosynthesis in leydig cells, widely believed to proceed through pregnenolone--greater than pregnenedione--greater than progesterone route catalyzed by 5 delta-3 beta-hydroxysteroid dehydrogenase and delta 5-delta 4-isomerase respectively is shown to pass through an alternate pathway mediated by superoxide dismutase and peroxidase. A built-in regulatory switch is incorporated in this route, with the superoxide dismutase inducible upon LH-stimulation of the leydig cells.

Mifepristone (Ru486) antagonizes monocyte chemotactic protein-3 down-regulation at early mouse pregnancy revealing immunomodulatory events in Ru486 induced abortion.

Problem:  The survival of an embryo bearing the paternal antigens within the immunocompetent environment of the maternal uterus renders ‘pregnancy’ to be a state of immunological paradox. The ratio of Th1/Th2 responses is crucial for pregnancy maintenance. Monocyte Chemotactic Protein‐3 (MCP3) is a pro‐inflammatory, CC chemokine and a Th1 effector which is capable of eliciting significant anti‐tumoral immune responses.

Over-expression of superoxide dismutase and lack of surface-thiols in spermatozoa: Inherent defects in oligospermia

The infertility associated with oligospermia had been suspected to be a direct consequence of the impairment in fertilizing ability of the spermatozoa rather than the presence of low sperm number per se. This study defines some of these impairments, which include an over expression of superoxide dismutase, poor superoxide anion radical generation capacity and a lack of sperm-surface thiols in oligospermia. The abnormal biochemical make-up of spermatozoa could explain their low fertilizing ability in case of oligospermia.