Effect of alerce (Fitzroya cupressoides) cell culture extract on wound healing repair in a human keratinocyte cell line.

BACKGROUND: Fitzroya cupressoides, commonly known as alerce, is an endemic conifer unique to southern South America. Alerce wood is renowned for its durability and resistance to biological degradation due to the presence of a particular class of secondary metabolite. Alerce extracts have been used in traditional medicine for different skin lesion treatments. AIMS: To develop a cell culture system to produce alerce extract and evaluate its cytotoxicity and effects on in vitro wound healing. METHODS: Cell cultures and aqueous extracts were prepared from alerce needles. Cytotoxicity was evaluated in keratinocytes (HaCaT line) and melanocites (C32 line) using the XTT assay. Wound healing was assayed with the scratch test in HaCaT cells, using mitomycin C to evaluate the role of cell division in the wound closure. RESULTS: Alerce cell culture extract has a significant effect on wound healing at different concentrations. No positive effects on the viability of normal and cancerous skin cells were observed. These results suggest that alerce extracts stimulate cell division in human skin epidermal cells in the context of wound repair. CONCLUSIONS: Bioactive compounds extracted from alerce cell cultures show promise as ingredients in dermocosmetic formulations, but further clinical studies are required to support these findings at the tissue level.

Experimental evidence for negative turgor pressure in small leaf cells of Robinia pseudoacacia L versus large cells of Metasequoia glyptostroboides Hu et W.C.Cheng. 1. Evidence from pressure-volume curve analysis of dead tissue.

This paper provides a mini-review of evidence for negative turgor pressure in leaf cells starting with experimental evidence in the late 1950s and ending with biomechanical models published in 2014. In the present study, biomechanical models were used to predict how negative turgor pressure might be manifested in dead tissue, and experiments were conducted to test the predictions. The main findings were as follows: (i) Tissues killed by heating to 60 or 80 °C or by freezing in liquid nitrogen all became equally leaky to cell sap solutes and all seemed to pass freely through the cell walls. (ii) Once cell sap solutes could freely pass the cell walls, the shape of pressure-volume curves was dramatically altered between living and dead cells. (iii) Pressure-volume curves of dead tissue seem to measure negative turgor defined as negative when inside minus outside pressure is negative. (iv) Robinia pseudoacacia leaves with small palisade cells had more negative turgor than Metasequoia glyptostroboides with large cells. (v) The absolute difference in negative turgor between R. pseudoacacia and M. glyptostroboides approached as much as 1.0 MPa in some cases. The differences in the manifestation of negative turgor in living versus dead tissue are discussed.

Experimental evidence for negative turgor pressure in small leaf cells of Robinia pseudoacacia L versus large cells of Metasequoia glyptostroboides Hu et W.C. Cheng. 2. Höfler diagrams below the volume of zero turgor and the theoretical implication for pressure-volume curves of living cells.

The physiological advantages of negative turgor pressure, Pt , in leaf cells are water saving and homeostasis of reactants. This paper advances methods for detecting the occurrence of negative Pt in leaves. Biomechanical models of pressure-volume (PV) curves predict that negative Pt does not change the linearity of PV curve plots of inverse balance pressure, PB , versus relative water loss, but it does predict changes in either the y-intercept or the x-intercept of the plots depending on where cell collapse occurs in the PB domain because of negative Pt . PV curve analysis of Robinia leaves revealed a shift in the x-intercept (x-axis is relative water loss) of PV curves, caused by negative Pt of palisade cells. The low x-intercept of the PV curve was explained by the non-collapse of palisade cells in Robinia in the PB domain. Non-collapse means that Pt smoothly falls from positive to negative values with decreasing cell volume without a dramatic change in slope. The magnitude of negative turgor in non-collapsing living cells was as low as -1.3 MPa and the relative volume of the non-collapsing cell equaled 58% of the total leaf cell volume. This study adds to the growing evidence for negative Pt .