Evaluation of seven sunscreens on hairless mouse skin

Abstract

The ability of seven sunscreens to protect against ultraviolet (UV)--induced inhibition of epidermal DNA synthesis was evaluated in vivo using a hairless mouse model. There were statistically significant differences among sunscreens in their ability to prevent UV-B (290 to 320 nm) inhibition of DNA synthesis. The protective factor (PF) of a sunscreen was arbitrarily defined as the ratio of the dose required to inhibit DNA synthesis by 50% with and without a sunscreen. The following PF values were determined: Coppertone 4, 4.4; Sundown Extra Protection, 8.4; Supershade 15, 21.0; Eclipse 15, 22.2; Blockout 15, 22.4; and Bain de Soleil 15, 27.6. Zinc oxide ointment protected against any significant suppression of DNA synthesis at all UV-B doses used. There was a relatively good correlation between the PF and the sun protection factor (SPF) claimed for each sunscreen by the manufacturer. However, the PF values determined in mouse skin were generally higher than the SPF values measured in human skin. Further studies are needed to determine if sunscreen substantivity (resistance to removal by water) can be evaluated by this technique.

Shedding light on sunscreens

“…In all of these methods, a standard reference formulation is tested alongside the sunscreen to serve as a control; this contains homomenthyl salicylate in the FDA and SAA methods, 63 2‐ethylhexyl p ‐methoxycinnamate in the DIN method, 63 and the choice of three reference formulations in the Colipa method. In addition to these well recognized methodologies, several other in vivo methods using human 64 , 65 or animal 66 –76 skin have been suggested but not become widely used.…”

Shedding light on sunscreens

“…In all of these methods, a standard reference formulation is tested alongside the sunscreen to serve as a control; this contains homomenthyl salicylate in the FDA and SAA methods, 63 2‐ethylhexyl p ‐methoxycinnamate in the DIN method, 63 and the choice of three reference formulations in the Colipa method. In addition to these well recognized methodologies, several other in vivo methods using human 64 , 65 or animal 66 –76 skin have been suggested but not become widely used.…”

A Review of Sunscreen Safety and Efficacy

“…The effect of PABA and other organic sunscreens on measures of DNA damage produced by acute exposure to UVR has been evaluated in vivo using primarily hairless mice. Walter (67) and Walter and DeQuoy (68) found that several organic sunscreens including PABA and its derivatives reduced UV-induced DNA damage in the skin of hairless mice. More recently, Ley and Fourtanier (69) reported that octyl methoxycinnamate (OMC), the most common UVB sunscreen used in the world, and terephthalylidene dicamphor sulfonic acid, a UVBAJVA filter, reduced the number of UV-induced pyrimidine dimers in epidermal DNA of hairless mice exposed to SSR.…”

Sunscreen Update

“…The sunscreens also protected against the UV‐induced increase in DNA synthesis measured at 48 hours after UV irradiation. Walter 7 also used UV‐induced suppression of epidermal DNA synthesis in mice to measure efficacy of various sunscreens. He found a relatively good correlation between protection in this experimental model compared to the SPFs claimed by sunscreen manufacturers.…”

Shedding light on sunscreens

“…In all of these methods, a standard reference formulation is tested alongside the sunscreen to serve as a control; this contains homomenthyl salicylate in the FDA and SAA methods, 63 2‐ethylhexyl p ‐methoxycinnamate in the DIN method, 63 and the choice of three reference formulations in the Colipa method. In addition to these well recognized methodologies, several other in vivo methods using human 64 , 65 or animal 66 –76 skin have been suggested but not become widely used.…”

A Review of Sunscreen Safety and Efficacy

“…The effect of PABA and other organic sunscreens on measures of DNA damage produced by acute exposure to UVR has been evaluated in vivo using primarily hairless mice. Walter (67) and Walter and DeQuoy (68) found that several organic sunscreens including PABA and its derivatives reduced UV-induced DNA damage in the skin of hairless mice. More recently, Ley and Fourtanier (69) reported that octyl methoxycinnamate (OMC), the most common UVB sunscreen used in the world, and terephthalylidene dicamphor sulfonic acid, a UVBAJVA filter, reduced the number of UV-induced pyrimidine dimers in epidermal DNA of hairless mice exposed to SSR.…”

Sunscreen Update

“…The sunscreens also protected against the UV‐induced increase in DNA synthesis measured at 48 hours after UV irradiation. Walter 7 also used UV‐induced suppression of epidermal DNA synthesis in mice to measure efficacy of various sunscreens. He found a relatively good correlation between protection in this experimental model compared to the SPFs claimed by sunscreen manufacturers.…”

Shedding light on sunscreens

“…In all of these methods, a standard reference formulation is tested alongside the sunscreen to serve as a control; this contains homomenthyl salicylate in the FDA and SAA methods, 63 2‐ethylhexyl p ‐methoxycinnamate in the DIN method, 63 and the choice of three reference formulations in the Colipa method. In addition to these well recognized methodologies, several other in vivo methods using human 64 , 65 or animal 66 –76 skin have been suggested but not become widely used.…”

A Review of Sunscreen Safety and Efficacy

“…The effect of PABA and other organic sunscreens on measures of DNA damage produced by acute exposure to UVR has been evaluated in vivo using primarily hairless mice. Walter (67) and Walter and DeQuoy (68) found that several organic sunscreens including PABA and its derivatives reduced UV-induced DNA damage in the skin of hairless mice. More recently, Ley and Fourtanier (69) reported that octyl methoxycinnamate (OMC), the most common UVB sunscreen used in the world, and terephthalylidene dicamphor sulfonic acid, a UVBAJVA filter, reduced the number of UV-induced pyrimidine dimers in epidermal DNA of hairless mice exposed to SSR.…”

Sunscreen Update

“…The sunscreens also protected against the UV‐induced increase in DNA synthesis measured at 48 hours after UV irradiation. Walter 7 also used UV‐induced suppression of epidermal DNA synthesis in mice to measure efficacy of various sunscreens. He found a relatively good correlation between protection in this experimental model compared to the SPFs claimed by sunscreen manufacturers.…”