Selenite and Ca2+homeostasis in the rat lens: effect on Ca-ATPase and passive Ca2+transport

Wang, Zaiqi; Bunce, G. E.; Hess, John L.

doi:10.3109/02713689308999466

Cited by 46 publications

(24 citation statements)

References 10 publications

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“…*p < 0.05 compared to the control group and #p < 0.05 compared to the Na 2 SeO 3 group. Values are reported as mean (n = 4) ± S.E reported by Hightower [71] which may be due to inhibition of Ca-ATPase activity [72]. Accumulation of calcium in the nucleus of the lens leads to m-calpain activation, proteolysis, insolubilization, and precipitation of crystallins.…”

Section: Discussionmentioning

confidence: 99%

Prevention and reversal of selenite‐induced cataracts by N‐acetylcysteine amide in Wistar rats

Maddirala

Tobwala

Karacal

et al. 2016

Acta Ophthalmologica

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Background: The present study sought to evaluate the efficacy of N-acetylcysteine amide (NACA) eye drops in reversing the cataract formation induced by sodium selenite in male Wistar rat pups. Methods: Forty male Wistar rat pups were randomly divided into a control group, an N-acetylcysteine amide-only group, a sodium selenite-induced cataract group, and a NACA-treated sodium selenite-induced cataract group. Sodium selenite was injected intraperitoneally on postpartum day 10, whereas N-acetylcysteine amide was injected intraperitoneally on postpartum days 9, 11, and 13 in the respective groups. Cataracts were evaluated at the end of week 2 (postpartum day 14) when the rat pups opened their eyes. N-acetylcysteine amide eye drops were administered beginning on week 3 until the end of week 4 (postpartum days 15 to 30), and the rats were sacrificed at the end of week 4. Lenses were isolated and examined for oxidative stress parameters such as glutathione, lipid peroxidation, and calcium levels along with the glutathione reductase and thioltransferase enzyme activities. Casein zymography and Western blot of m-calpain were performed using the water soluble fraction of lens proteins. Results: Morphological examination of the lenses in the NACA-treated group indicated that NACA was able to reverse the cataract grade. In addition, glutathione level, thioltransferase activity, m-calpain activity, and m-calpain level (as assessed by Western blot) were all significantly higher in the NACA-treated group than in the sodium selenite-induced cataract group. Furthermore, sodium selenite-injected rat pups had significantly higher levels of malondialdehyde, glutathione reductase enzyme activity, and calcium levels, which were reduced to control levels upon treatment with NACA.

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Section: Discussionmentioning

confidence: 99%

Prevention and reversal of selenite‐induced cataracts by N‐acetylcysteine amide in Wistar rats

Maddirala

Tobwala

Karacal

et al. 2016

Acta Ophthalmologica

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“…PMCA activity was found in rat epithelial cells but not in the nucleus [1] . Furthermore, only PMCA1b was detected in the epithelium of rat lens and no PMCA isoform was observed in the lens nuclear region [41,42] . These results from rat lenses are in agreement with our findings from human lenses that PMCA isoforms are expressed by the lens epithelial cells but not by the nucleus or cortex [39] .…”

Section: What Pmca Isoforms Are Present In the Human Lens And Where Amentioning

confidence: 90%

Plasma Membrane Ca2+-ATPase Isoform Expression in Human Cataractous Lenses Compared to Age-Matched Clear Lenses

Marian¹,

Mukhopadhyay

Borchman

et al. 2008

Ophthalmic Res

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The plasma membrane calcium ATPase (PMCA) pump is the major mechanism by which calcium is removed from the lens. The aim of this study was to determine if mRNA and proteins levels of PMCA isoforms changed with age or lens opacity. mRNA was quantified using a quantitative real-time reverse transcription polymerase chain reaction assay (RT-PCR). PMCA protein levels were quantified using Western blot analysis. No PMCA mRNA or proteins were detected in human lens fiber cells. The mRNA and protein levels of PMCA1, 3 and 4 in the epithelium of cataractous lenses were similar to those of epithelium from age-matched clear lenses and were also the same in younger lenses. PMCA2 mRNA and protein levels were 1.6–2.5 times higher, respectively, in cataractous lenses compared to age-matched clear lenses. Elevated PMCA2 expression in cataractous lenses might be a compensatory mechanism to overcome higher intracellular calcium levels in cataract.

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“…Ca 2ϩ -ATPase activity was calculated as the difference in phosphate liberation measured in the presence and absence of Ca 2ϩ . 21) RNA Preparation Lenses were removed from UPLR, SCR and ICR, and snap-frozen in liquid nitrogen. Total RNA was prepared from each individual lens by the acid guanidium thiocyanate-phenol-chloroform extraction method 22) using Trizol reagent (Life Technologies Inc., Rockville, U.S.A.).…”

Section: ؉mentioning

confidence: 99%

Comparison of the Mechanisms of Cataract Development Involving Differences in Ca2+ Regulation in Lenses among Three Hereditary Cataract Model Rats

Nagai

Ito

Takeuchi

et al. 2008

Biological & Pharmaceutical Bulletin

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Cataracts are the major cause of blindness with an estimated 16 million people affected worldwide.1) The mechanism of cataract development is complicated and involves various factors including genetic factors, diabetes, smoking, nutrition, the cumulative effect of X-rays, ultraviolet irradiation, and alterations in both endocrine and enzymatic equilibria.2-7) Currently, radical oxygen species, especially those induced by UV rays in sunlight, are considered to be important in perturbing lens homeostasis. Following exposure to radical oxygen species, the calcium ion (Ca 2ϩ ) content in lens cells becomes elevated. 8,9) An elevated Ca 2ϩ content in the lens has been shown to activate calpain, a Ca 2ϩ -dependent protease. Furthermore, the degradation of lens proteins such as crystallin proteins results in an opaque lens. 8,9) Over the past several decades, there have been many studies exploring the mechanisms of cataract development.8) However, due to uncertainties regarding efficacy and safety, a potent anticataract drug for human cataracts has not yet been introduced.In studies to develop anti-cataract drugs, the selection of the experimental animal is very important. The UPL rat (UPLR), Shumiya cataract rat (SCR) and Ihara cataract rat (ICR/f; ICR) are hereditary cataractous strains, and it has been shown that these rats provide useful models in studies to develop anti-cataract drugs. Previous investigations have revealed that the proteolyses of some crystallins are significantly enhanced in UPLR, SCR and ICR lenses. [10][11][12][13][14] The Ca 2ϩ content in the cataractous lenses of UPLR, SCR and ICR are higher than in the lenses of Wistar rats, and autolytic products formed by calpain can also be detected in cataractous lenses.11,12,15,16) It is noteworthy that the cataracts formed in these rat models are not diabetic cataracts. Therefore, these rats have been used for studies to develop anti-cataract drugs. However, we recently reported that the increase in Ca 2ϩ content in the lenses of these rats is inhibited by an aminoguanidine, a selective inhibitor of inducible nitric oxide synthase (iNOS), and that the mechanism of Ca 2ϩ enhancement via iNOS among these rat models may differ. [17][18][19] Therefore, it is very important to clarify the mechanisms underlying the dysfunctions in Ca 2ϩ regulation in UPLR, SCR and ICR during cataract development.In the present study, we compare the mechanisms of the decrease in Ca 2ϩ outflow in the lenses of UPLR, SCR and ICR during cataract development. MATERIALS AND METHODSAnimals Cataractous UPLR, SCR and ICR were used in this study. The UPLR and ICR were provided by Meijo University (Aichi, Japan), and SCR was a gift from the Tokyo Metropolitan Institute of Gerontology (Tokyo, Japan). They were housed under standard conditions (12 h/d fluorescent light (07:00-19:00), 25°C room temperature), and allowed free access to a commercial diet (CE-2, Clea Japan Inc., Tokyo, Japan) and water. All procedures were performed in accordance with the Association for Research in Vis...

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Selenite and Ca²⁺homeostasis in the rat lens: effect on Ca-ATPase and passive Ca²⁺transport

Cited by 46 publications

References 10 publications

Prevention and reversal of selenite‐induced cataracts by N‐acetylcysteine amide in Wistar rats

Prevention and reversal of selenite‐induced cataracts by N‐acetylcysteine amide in Wistar rats

Plasma Membrane Ca<sup>2+</sup>-ATPase Isoform Expression in Human Cataractous Lenses Compared to Age-Matched Clear Lenses

Comparison of the Mechanisms of Cataract Development Involving Differences in Ca2+ Regulation in Lenses among Three Hereditary Cataract Model Rats

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