12/15-Lipoxygenase deficiency reduces densities of mesenchymal stem cells in the dermis of wounded and unwounded skin.

BACKGROUND: Mesenchymal stem cells (MSCs) promote skin healing. 12/15-Lipoxgenase (LOX) is crucial in producing specific lipid mediators in wounded skin. The consequences of 12/15-LOX deficiency in MSC densities in skin are unknown. OBJECTIVES: To determine the effect of 12/15-LOX deficiency in MSC densities in wounded and unwounded dermis. METHODS: Full-thickness skin incisional wounds were made to 12/15-LOX-deficient (12/15-LOX(-/-) ) and wild-type (WT) C57BL/6 mice. Wounded skin was collected at 3, 8, or 14 days postwounding (dpw). MSCs were analysed in skin sections using histology. 12S- or 15S-hydroxy-eicosatetraenoic acid (HETE) was analysed using a reversed-phase Chiral liquid chromatography-ultraviolet-tandem mass spectrometer. RESULTS: There were more stem cell antigen (Sca)1(+) CD29(+) MSCs (cells/field) at 3, 8, and 14 dpw, more Sca1(+) CD106(+) MSCs at 3 and 14 dpw in the wounded dermis, more MSCs in unwounded dermis of WT mice compared with 12/15-LOX(-/-) mice, and more MSCs in the wounded dermis than in the unwounded dermis. For 12/15-LOX(-/-) dermis, Sca1(+) CD106(+) MSCs peaked and Sca1(+) CD29(+) MSCs reached a flat level at 8 dpw. However, for the WT dermis, MSCs increased from 8 to 14 dpw. There were more Sca1(+) CD106(+) MSCs than Sca1(+) CD29(+) MSCs in the 12/15-LOX(-/-) wounded dermis at 8 dpw. However, there were more Sca1(+) CD29(+) MSCs in the 12/15-LOX(-/-) than Sca1(+) CD106(+) MSCs in the WT wounded dermis at 3 dpw, and Sca1(+) CD106(+) MSCs and Sca1(+) CD29(+) MSCs were at comparable levels in other conditions. 12/15-LOX deficiency suppressed levels of 12/15-LOX protein and their products, 12S-HETE and 15S-HETE, in wounds. CONCLUSIONS: 12/15-LOX deficiency reduces MSC densities in the dermis, which correlates with the suppressed 12/15-LOX pathways in wounded and unwounded skin.

Rapid action of oestradiol against hydrogen peroxide-induced oxidative stress in cataractous lens epithelium: an in vitro study.

PURPOSE: To evaluate the short-term protective effects of oestradiol against damages because of oxidative stress in human lens epithelial cells (LECs). METHODS: The central zone of human lens epithelium was obtained from the cataract surgery and cultured in MEM culture medium. These cultured LECs were treated with 17beta-oestradiol for varying time intervals from 1 to 5 min followed by treatment with H(2)O(2) (5 x 10(-6) M) in the culture medium. Catalase activity was measured to access the oxidative stress levels. RESULTS: LECs exposed to H(2)O(2) (5 x 10(-6) M) showed a fourfold increase in catalase activity (407.03+/-89.11 U/microg protein) after 6 h when compared to cultured unexposed LECs (97.124+/-9.4 U/microg protein). When the cultured LECs were treated with oestradiol (5 x 10(-8) M) before H(2)O(2) treatment, the increase in catalase activity was inhibited, whereas simultaneous and post-treatments showed no effect. The catalase activity of LECs pretreated with oestradiol for 1, 2, 3, and 5 min was 259.92+/-18.37, 200.24+/-14.39, 140.50+/-19.83, and 110.01+/-14.66, respectively (P<0.0001). CONCLUSION: Antioxidative enzymes are synthesized in response to the oxidative stress signal. Upon treatment with oestrogen catalase is not synthesized. The pretreatment time of oestrogen required for its antioxidative effect can be seen within 5 min indicating non-genomic mode of action of oestrogen.