Dose-response effects of acute ultraviolet irradiation on antioxidants and molecular markers of oxidation in murine epidermis and dermis

Poster Presentations

93

480 DOSE-

AND TIME-DEPENDENT

SUPEROXIDE S&a&.

DISMUTASE

Yumiko

Depanment

Nonaka

EFFECT

ACTIVITY

Osamu

of Demxxology.

Ishikawa.

Karunori

Gunma University

Effect of acute UVB irradiation was investigated

using hairless mice.

sacrificed

1. 3 and 7 days after irradiation. The dorsal

reduction

method.

mJ/cm’ (18.6*3.9 (12.8i2.0,

were assayed

The SOD activities U/mg protein;

p < 0.02) significantly

SOD activities

dismutase

Mivaa

Maebashi,

(SOD) activity

Japan

in the skin

mea&SD,

with

at a time.

The mice were

Age matched

unbndiated

mice served as

and stored

in liqutd

sp-ectrophotomeuically

on the 1st day after irradiation

increased

while at the dose of 1Mx) mJ/cm” (6.9il

and Yoshiki

ON

m

respectively

skin was excised

SOD activities

Ohnishi

SKIN.

Female mice (aged 6 weeks) were irradiated

controls. examination.

UVB IRRADIATION MOUSE

School of Medicine,

on supemxide

UVB at doses of 40, 200 and loo0 &/cm’, trunk

OF ACUTE

IN HAlRLESS

nitrogen

until

by cytochrome

c

at the dose of 40

p -z 0.001) and at the dose of 200 ml/cm’ when compared

S) decreased

with the controls

(9.2+1.9),

SOD activities were noticed

The

at the doses of both 40 and 200 mJlcm2 on the 3rd and 7th day after

irradiation

returned

gradually

decreased.

to the level of controls,

though those at the dose of 1000 ml/cm2

These results indicate that the increased

UVB b-radiation at relatively

low doses decreased

SOD activities

induced by

in a few days and that UVB “-radiation

at a htgh dose does not increase those activities but impair the antioxidant

mechanisms.

478

481

DOSE-RESPONSE EFFECTS OF ACUTE ULTRAVIOLET IRRADIATION ON ANTIOXIDANTS AND MOLECULAR MARKERS OF OXIDATION IN MURINB EPIDERMIS AND DERMIS. Yasuko Shtndo. Eric WITT. Derick Ha” and Lester PACKER. Department of Molecular and Cell Biology. 251 Life Sciences Addition. University of Berkeley, USA In a previous study we examined the antioxidant defense system of the epidermis and dentus. We fou”d;l) Most antioxidants(enzymic and “on-rnzymic) are present I” higher concentrations I” epidermis than dermis I” hairless mice 2) When mice were exposed to a single large dose of simulated solar light L” viva the concentrations of many aouoxidants decreased dramaticallv I” both eoidetmis and dermis I” the present study we &ted a range of doses of UV Iaght commomly or

THE DIFFERENT EFFECTS OF SUNSCREENS ON UVB ERYTHEHA AND LANGERHANS CELLS DEPRESSION. Tsun,na Hiyag~Abdul__&rtan Bhutto and Shi.eeo Nan&a. Dep*rtme”t of Dermatology. Faculty of Medicine, University of Ryukyus, Okinawa. Japan It is a we,, know” fact that ““B SUPreSSeS Langerhans Sunscreens are widely used celItLC> “umber an.3 *unction. ““B erytherna. But there IS very ,,ttie to supress SUnScreenS On the Ix. I” studies on the effects of the this study. we invest,gate S”“scree” effects 0” LC a* the

California.

occasionally

encountered to elucidate the patterns of antioxidant

response and the cellular

damage over such a range. Hanless mice were Irradiated with simulated solar light at doses of 2.5.12.5, and 2510ulelcm2 and enzymic and “oo-enzymx antmxidants as well as lipid hydroperoxides were measured in both epidermis and dermis Amone the “on-e”znmc antioxidants. two distinctlv different dose resoonse patterns were see” Ascorbate was rapidly depleted at doses hetwee” 0.5J/cmz but was less affected hetwee” 5-25 J/cm2 In contrast. glutathione. uhiquinollone. and a-tocophcml levels remained approxmtately equal to convol levels between 0.(J/cm’. then decreased trr varying degrees‘ from 5.25J/cm2; uhtqoiool was almost completely depleted whtlc atocopherol dropped only 30 % The concentratto” of lipid hydroperoxldes increased throughout the dose ra”ge These results may he explained panly by direct destructton of some antioxidants hy UV light. partly by the separate antioxidant functions 01 thr compounds, and panly by recycling. of some anttoxidantr at the expe”w of others

in There was “o difference between 15 and 28 control mice. FroP these reS”lts. It appear* that SPF Of sunset-eens. sunsereen SoPresseS the ““B erVthet”a an* Is s,ze, but no t This “lean* that the PaSSibllIty exists the “umber of LC. tatIt subscreens do not protect ageinst ““B supress1on of needed ,” function. Further studies Will be LC investigate the effect of SunsCreens using lany nore other indicators. including eryttlema.

479

482

CHRONIC

ULTRAVIOLET

RADIATION-INDUCED

OLYCOSAMJNOGLYCANS -“ori k

OF HAIRLESS

Ohnishi.

Dermatology, Changes

Osamu

Gunma University

MICE.

weeks) wen irradiated

were investigated

Yumiko

and Yoshiki

Ishikewa

School of Medicine.

in the ski” glycosami”oglycans

(UV-A, UV-B) radiation

CHANGES

Not&a.

Mivachi,

Maebashi,

ossue the skt” was minced

by chronic

mice.

and age-matched

unitradiated

into pieces, defatted

deproteinired

with IO I

with 0.1 % cetylpyridinium

After

with

chondroitinase-AC

disaccharides

methyl-5.pyrasolone

ulmviolet

mice were sacrificed dried and weighed.

by high-pafomtance

chloride,

To

with HCI, digested

acid and dialyzed.

Crude GAGS

washed with ethanol and dried.

or chondroitinase-ABC,

were analyzed

after

After removal of the subcutaneous

with acetone,

uichloroacetic

were precipitated digestion

of

Female mice (aged 6

isolate crude GAGS, the skin was aeared with 2 I NaOH. neutralized

unsaturated

Department

three times a week with UV-A (30 J/cmz) or UV-B (40 ml/cm’).

The UV-A or UV-B irradiated

6 and I2 weeks, and dorsal mmk skins were excised.

with pronase,

Katsu

Japan

(GAGS) induced using hairless

IN THE SKIN

using precolumn

GAG-derived

labeling

liquid chromatography.

wtth l-phenyl-3. We found contents

of main disaccharides (hyalumnic acid-derived ADi-HA and demntan sulfate-derived ADi-4s) tended to increase after UV-B exposures (13 1 % and 1 I7 I of the conuol mice at 12 weeks respectively)

and decrease

results suggest that chronic

GAGS metabolism

radiatton

after UV-A exposures of UV-A

of hairless mice skm

(84 % and 80 C). These

or UV-B has different

effects

on the

induced a marked decrease “f A 100 .J/c.~ of UVB There was no change of LC “umber when the in the mice. However. the s,ze B”d 28 SPP of SUnSCreenS vet-e used. LC decreasesd I” SUnSCreen group, Compared With ttlo*e

LC 15 of

PHOTOTOXIC POTENTIAL OF NEW QUINOLONE ANTIBACTERIAL AGENTS IN RABBITS. Shoshi Yasuda and Takuo Tsuii, Department of Demutology. Nagoya City University Medical School, Nagoya, Japan As new quinolone antibacterial agents become widely used, the numbers of reports of photosensitivity reactions to these drugs have been increased. The purpose of this study is to examine the phototoxic potentials of several new quinolone antibacterial agents using rabbits, considering the mechanism of the photosensitivity. Six kinds of drues. lomefloxacin (LFLX). enoxacin (ENX). ofloxacm (OFLX). ciprofloxaci<(‘?PFX). tosuflox&in (*X) and “o;fioxa& (NFLX). were examined in this study. Five Japanese white rabbits were used for each drug. The shaved abdominal ski” of the rabbit was irradiated with UVA. I .2 J/cm2 to 2 I J/cm2 with 50% increments, 1 h after oral administration of drugs. The light source used was Toshiba FL32SBL equipped with window glass. Minimal erythema doses were determined 48 h after irradtation. Dosage of each drug required for producing erythema by irradiating 9 J/cm2 UVA (DOSE 91, mglkg) was calculated from dose-response CUNCS. The DOSE 9~ values of LFLX, ENX, OFLX, CPFX and NFLX were 46.6. 128.6. 288.5,441.7 and 640 mg/kg, respectively. Thts order was relevant to the incidence of photosensitivity reactions clinically observed. No phototoxic reactions were observed with TFLX even when maximal dose (at least 640 mgikg) was give”. Among these new quinolone antibacterial agents LFLX showed the highest phototoxic potency and it is suggested to be most carefully used for men.