Cactus cladodes (Opuntia humifusa) extract minimizes the effects of UV irradiation on keratinocytes and hairless mice

Figures & data

Table 1. Description of the experimental groups.

Groups	UVB irradiation		Oral administration (in drinking water)	Topical application (in 15% ET)
Positive control	Normal	–	–
Negative control	UVBC	UVB irradiation	water-	15% ET
Oral treatment	OL	UVB irradiation	0.1% OHE	–
	OH	UVB irradiation	0.5% OHE	–
Topical treatment	TL	UVB irradiation	–	0.2 mg/cm^2 OHE
	TH	UVB irradiation	–	0.4 mg/cm^2 OHE

OHE: Opuntia humifusa extract; ET: eucalyptol. Normal: drinking water without OHE, no UVB irradiation; UVBC: drinking water without OHE plus UVB irradiation; UVB-ET: topical application of vehicle (15% eucalyptol); OL: 0.1% OHE in drinking water plus UVB irradiation; OH: 0.5% OHE in drinking water plus UVB irradiation; TL: topical application of OHE at 0.2 mg/cm² plus UVB irradiation; TH: topical application of OHE at 0.4 mg/cm² plus UVB irradiation.

Table 2. Relative cell viability of OHE, with or without UVB irradiation (% of normal control).

OHE concentration(μg/mL)	Without UVB irradiation	With UVB irradiation
0	100.0 ± 7.89	81.6 ± 4.2
10	103.2 ± 9.7	83.4 ± 7.2
25	97.3 ± 8.5	82.6 ± 2.8
50	101.3 ± 7.2	80.5 ± 3.8
100	96.8 ± 6.5	80.7 ± 5.2

OHE: Opuntia humifusa extract; UVB: ultraviolet B.

Figure 1. mRNA expression of HAS1, HAS2 and HAS3 in UVB-irradiated HaCaT cells was affected by OHE treatment in a dose-dependent manner. (A) HAS1 mRNA levels, (B) HAS2 mRNA levels, (C) HAS3 mRNA levels. All results expressed a one-fold change compared to the UV-treated control group (UV-Con). HAS: hyaluronic acid synthase; OHE: O. humifusa extract; Normal: untreated HaCaT cells; UVBC: UVB-irradiated HaCaT cells (without OHE treatment). The values are the mean ± standard deviation (SD) (n = 3). Different letters indicate significant differences (p < 0.05) among the treatments as indicated by Duncan’s multiple range test.

Figure 2. mRNA expression of HYAL in UVB-irradiated HaCaT cells was affected by OHE treatment in a dose-dependent manner. All results expressed a onefold change compared to the UV-Con. HYAL: hyaluronidase; OHE: O. humifusa extract; Normal: untreated HaCaT cells; UVBC: UVB-irradiated HaCaT cells (without OHE treatment). The values are the mean ± standard deviation (SD) (n = 3). Different letters indicate significant differences (p < 0.05) among the treatments as revealed by Duncan’s multiple range test.

Figure 3. Epidermal thickness, CD44 and HABP expression in the skin of UVB-irradiated hairless mice treated with OHE. (A) H&E staining (epidermal thickness), (B) CD44 distribution and expression, (C) HABP distribution and expression, Normal: drinking water without OHE, no UVB irradiation; UVBC: drinking water without OHE plus UVB irradiation; UVB-ET: topical application of vehicle (15% eucalyptol); OL: 0.1% OHE in drinking water plus UVB irradiation; OH: 0.5% OHE in drinking water plus UVB irradiation; TL: topical application of OHE at 0.2 mg/cm² plus UVB irradiation; TH: topical application of OHE at 0.4 mg/cm² plus UVB irradiation. The values are the mean ± standard error of the mean (SEM) (n = 6). Different letters indicate significant differences (p < 0.05) among the groups as indicated by Duncan’s multiple range test.

Figure 4. Hyaluronic acid content, and mRNA levels of HAS and HYAL in the skin of UVB-irradiated hairless mice treated with OHE. (A) HA content, (B) HAS mRNA expression and expression, (C) HYAL mRNA expression, Normal: drinking water without OHE, no UVB irradiation; UVBC: drinking water without OHE plus UVB irradiation; UVB-ET: topical application of vehicle (15% eucalyptol); OL: 0.1% OHE in drinking water plus UVB irradiation; OH: 0.5% OHE in drinking water plus UVB irradiation; TL: topical application of OHE at 0.2 mg/cm² plus UVB irradiation; TH: topical application of OHE at 0.4 mg/cm² plus UVB irradiation. The values are the mean ± standard error of the mean (SEM) (n = 6). Different letters indicate significant differences (p < 0.05) among the groups as indicated by Duncan’s multiple range test.

Figure 5. Transepidermal water loss and erythema value in the skin of UVB-irradiated hairless mice treated with OHE. (A) Transepidermal water loss in the dorsal mouse skin was examined using the Tewameter TM 300. (B) The erythema level was determined using a MexameterMX18. Normal: drinking water without OHE, no UVB irradiation; UVBC: drinking water without OHE plus UVB irradiation; UVB-ET: topical application of vehicle (15% eucalyptol); OL: 0.1% OHE in drinking water plus UVB irradiation; OH: 0.5% OHE in drinking water plus UVB irradiation; TL: topical application of OHE at 0.2 mg/cm² plus UVB irradiation; TH: topical application of OHE at 0.4 mg/cm² plus UVB irradiation. The values are the mean ± standard error of the mean (SEM) (n = 6). Different letters indicate significant differences (p < 0.05) among the groups as indicated by Duncan’s multiple range test.