Hidekazu Murano

Inhibition of Steroid-Induced Cataract in Rat Eyes by Administration of Vitamin-E Ophthalmic Solution

The efficacy of a vitamin-E (VE) ophthalmic solution was evaluated on a newly developed rat steroid-induced cataract model. Brown Norway rats irradiated with 2 Gy X-ray, right eyes only, were divided into 5 groups: the control group; 2 steroid (1 mg/kg/day)-treated groups with topic (Top) and systemic (Sys) administration, and 2 VE-treated groups, 1 with the same treatment as the Top group with the addition of 5% VE twice a day (Top + VE) and 1 with the same treatment as the Sys group with 5% VE twice a day (SYS + VE). The lens changes were documented with a Scheimpflug camera and changes in light scattering were evaluated quantitatively. The VE-treated groups (Top + VE and Sys + VE) showed a significant inhibition of the increase in the opaque area compared with each of the non-VE-treated groups. The VE ophthalmic solution was strong enough to prevent steroid-induced cataract in rats.

Location and severity of UVB irradiation damage in the rat lens

We investigated the location and severity of lens opacities and epithelial alterations following ultraviolet-B (UVB) irradiation in vivo, using Brown Norway rats. A group of 9 rats received 65 mJ/cm2 UVB irradiation from overhead lamps every 6 days. Lens changes were documented and evaluated by an anterior eye segment analysis system. Lens epithelial cells were examined postmortem in flat preparations. After 8 weeks of the irradiation schedule (total dose: 0.6 J/cm2), an anterior polar opacity was apparent; at 16 weeks, the opacities had progressed more deeply into the cortex. At postmortem examination, cells in the central region displayed disorganization, clumping, some pyknotic nuclei and mitosis. There were deeper opacities and cell damage was more severe above the central horizontal plane than below it. This present study demonstrated that UVB damage differed in the superior and inferior parts divided by a horizontal plane through the lens anterior pole, when the UVB source was above and there was no reflection from below or laterally. The lens epithelial cells, and associated lens fibers, are the first target of UVB irradiation.

Transfer of immune components from rabbit autoimmune cardiomyopathy into severe combined immunodeficiency (SCID) mice induces cardiomyopathic changes

Background: Growing evidence suggests that autoimmune mechanism plays an important role in the pathogenesis of cardiomyopathy. The purpose of this study was to investigate whether passive transfer of IgG and/or lymphocytes from rabbits with autoimmune cardiomyopathy is able to reproduce cardiomyopathic changes in severe combined immunodeficiency (SCID) mice. Methods and results: SCID mice were injected intraperitoneally with IgG and/or peripheral blood lymphocytes (PBL) from either rabbits immunized with both β1-adrenoceptor peptide and M2-muscarinic receptor peptide (β1+M2 group) or rabbits with adjuvant (N group). Thirty five SCID mice were divided into seven groups; N-IgG, N-PBL, N-IgG & PBL, (β1+M2)-IgG, (β1+M2)-PBL, (β1+M2)-IgG & PBL and control groups. Heart weight in three (β1+M2) groups were significantly increased. All mice in three (β1+M2) groups showed high titer of rabbit anti-β1 adrenocepter autoantibodies, and 4 mice in the (β1+M2)-PBL group and 3 mice in the (β1+M2)-IgG & PBL group showed a significant increase in titer of rabbit anti-M2-muscarinic receptor autoantibodies. Focal infiltration of inflammatory cells in the myocardium was observed in the (β1+M2)-IgG & PBL group. In the (β1+M2)-PBL group and (β1+M2)-IgG & PBL group, cardiomyocyte diameters were significantly increased. Some myocytes of the (β1+M2)-IgG & PBL group exhibited intracellular edema, clumps of Z-band and increased numbers of mitochondria by using electron microscopy. Conclusion: Transfer of IgG and PBL from rabbits immunized with combined β1 and M2 peptides was able to reproduce the early stage of cardiomyopathic changes in SCID mice

Differences in naphthalene cataract formation between albino and pigmented rat eyes.

The progression of naphthalene cataracts induced in Brown-Norway rats and Sprague-Dawley rats was compared. The quality of lens changes was basically the same in both strains. However, the cataract progression in Brown-Norway rats showed regularity and was fast as compared with the progression in Sprague-Dawley rats. The cataract development could be divided into three stages. Stage 1: formation of water clefts below the anterior lens capsule (shallow cortex) was observed as the initial change; stage 2: these water clefts extended into the deeper cortical layers, and a semicircular opaque band at the deeper cortical region becomes visible; stage 3: a retroillumination image revealed a ring shadow formation - slit image observation showed wedge-shaped cortical and deeper cortical zonular opacification as the final stage. The expression of these three stages in Sprague-Dawley rats is less uniform and timely delayed as compared with Brown-Norway rats.

Distributional Change of Alpha-Tocopherol in the Rat Lens with Age

Concentration of alpha-tocopherol (alpha-Toc.) in the rat lens (1, 4 and 12 months old) was determined in single lenticular layers using gas chromatography and mass spectrometry. The highest concentration of alpha-Toc. in lens was found in the nucleus, followed by the deeper anterior and deeper posterior cortices, the shallow anterior and shallow posterior cortices, and the equatorial region. The topographic alpha-Toc. distribution in the lens did not differ between lenses of 1-, 4- and 12-month-old rats. A significant decrease of alpha-Toc. concentration was seen in lenses of 4- and 12-month-old rats compared to those 1 month old. Concentration and distribution in 4- and 12-month-old rat lenses were almost the same. The concentration of alpha-Toc. in the lens changes in relation to age.

A Mild Progression Type of Naphthalene-Induced Cataract in Brown-Norway Rats

Naphthalene-induced rat cataract is a useful experimental cataract--however, because of its short survival period, studies using this model have been for limited purposes. Based on the consideration that the short survival might be caused by systemic toxicity of an overdose of naphthalene administration (1 g/kg body weight every other day), the authors successfully established a naphthalene-induced cataract with mild progression in Brown-Norway rats. The naphthalene administration proposed is to initially administer 0.5 g/kg and after a 1-week interval 1 g/kg of 10% naphthalene once or twice a week through a stomach tube. While the type of lens opacification induced in the two groups administered once and twice a week, respectively, was the same as that seen by the previous administration method, the progression of lens opacification seen in the groups showed a dose-dependent increase. The survival rate in the rats given naphthalene every other day according to the old method was 50% at the 6th week and 0% at the 9th week. Survival of the two new groups was 70 and 60% at the 30th week, respectively. This new type of naphthalene-induced rat cataract should be a suitable model for long-term observations.