Heat shock protein 65 immunoreactivity in experimentally induced polymorphic light eruption

The protection role of human growth hormone on skin cells following ultraviolet B exposure

BACKGROUND

Ultraviolet-B (UVB) radiation is the leading environmental cause of skin damage and photoaging. The epidermis and dermis layers of the skin mainly absorb UVB. UVB stimulates apoptosis, cell cycle arrest, generation of reactive oxygen species, and degradation of collagen and elastin fibers.

OBJECTIVE

This study investigated the potential of human growth hormone (hGH) in protecting the skin fibroblasts and keratinocytes (HFFF-2 and HaCaT cell lines) from UVB-induced damage.

METHODS

The MTT assay was performed to evaluate UVB-induced mitochondrial damage via assessing the mitochondrial dehydrogenase activity, and flow cytometry was carried out to investigate the effects of UVB and hGH on the cell cycle and apoptosis of UVB-irradiated cells. In addition, the fold change mRNA expression levels of Type I collagen and elastin in HFFF-2 cells were evaluated using the qRT-PCR method following UVB exposure.

RESULTS

We observed that treatment of cells with hGH before UVB exposure inhibited UVB-induced loss of mitochondrial dehydrogenase activity, apoptosis, and sub-G1 population formation in both cell lines. We also found that hGH-treated HFFF-2 cells showed up-regulated mRNA expression of Type I collagen, elastin, and IGF-1 in response to UVB irradiation.

CONCLUSION

These findings suggest hGH as a potential anti-UVB compound that can protect skin cells from UVB-induced damage. Our findings merit further investigation and can be used to better understand the role of hGH in skin photoaging.

Chlamydia trachomatis Infection and Photosensitive Dermatoses

BACKGROUND

Photosensitivity to Chlamydia trachomatis has been described in almost 50% of chronic cases of lymphogranuloma venereum (LGV) caused by L1, L2 or L3 serovars. Photosensitivity in non LGV strains of C trachomatis has not been studied. We studied the association of various photosensitive dermatoses with C trachomatis infection in non LGV cases.

METHODS

Sera of all the cases of photosensitivity, melasma, chronic actinic dermatitis (CAD), polymorphic light eruption (PLE), actinic prurigo (AP) and rosacea were tested for the presence of IgM, IgG and IgA antibodies to C trachomatis by ELISA method. The results were compared with 30 healthy controls.

RESULT

Seventeen (25.53%) of 57 cases of photosensitivity as against two (6.67%) controls were seropositive for IgM/IgG/IgA antibodies, a statistically significant difference (χ(2) 6.18, p 0.013). Similarly, significantly higher seropositivity was observed in 12 (25.53%) of 47 cases of melasma (χ(2) 4.38, p 0.0363) and six (46.15%) of 13 cases with CAD (χ(2) 6.91, p 0.0086). Although higher proportion of patients of rosacea [five (31.25%) of 16 cases] and PLE [four (25.0%) of 16 cases] were seropositive, the difference was not statistically significant (χ(2) 3.23, p >0.05, OR 6.36, CI 95% 0 to 48 and χ(2) 3.09, p 0.078, OR 4.67, CI 95% 5 to 41 respectively). There was no association of AP.

CONCLUSION

The observations suggest that C trachomatis infection in non LGV cases is an important cause of PS, melasma and CAD. It appears to be an important cause of rosacea and PLE. We recommend that all cases of photosensitivity, melasma, CAD, PMLE and rosacea and their spouses/sexual contacts be investigated for C trachomatis infection.