Effects of ageing and long-term subcultivation on collagen lattice contraction and intra-lattice proliferation in three rat cell types

Screening of medicinal and edible plants in Okinawa, Japan, for enhanced proliferative and collagen synthesis activities in NB1RGB human skin fibroblast cells

To identify plants with bioactive potential for skin care, methanol extracts of 56 plant parts from 47 medical and edible plants cultivated in Okinawa were tested for their proliferative effects on NB1RGB skin fibroblast cells. Extracts from six plants, Bischofia javanica, Colocasia esculenta, Melaleuca alternifolia, Piper angustifolia, Jasminum sambac, and Curcuma longa, showed higher NB1RGB cell proliferation activity (>10%) than the control, at various concentrations. Among the six extracts, only the C. longa extract caused an increase in collagen synthesis in NB1RGB cells, as compared to treatment with the positive control, ascorbic acid (AsA). Expression of the collagen synthesis marker, transforming growth factor-β1, was higher after treatment with the C. longa extract than with AsA.

Occlusive dressings and the healing of standardized abrasions

CONTEXT

Acute skin trauma during sport participation, resulting in partial-thickness abrasions, is common. The limited investigations focusing on the acute wound environment and dressing techniques and the subsequent lack of evidence-based standards complicate clinical wound care decisions.

OBJECTIVE

To examine the effects of occlusive dressings on healing of standardized, partial-thickness abrasions.

DESIGN

Controlled, counterbalanced, repeated-measures design.

SETTING

University laboratory.

PATIENTS OR OTHER PARTICIPANTS

Sixteen healthy women (n = 10) and men (n = 6).

INTERVENTION(S)

Four standardized, partial-thickness abrasions were inflicted. Film, hydrogel, and hydrocolloid occlusive dressings and no dressing (control) were applied. Participants returned on postwound days 1, 3, 5, 7, 10, and 14 for digital imaging. Wound healing time was measured by change in wound contraction (cm(2)) and change in wound color (chromatic red) and luminance in red, green, and blue color values.

MAIN OUTCOME MEASURE(S)

Wound contraction, color (chromatic red), and luminance.

RESULTS

A day-by-dressing interaction was found for wound contraction, color, and luminance. Post hoc testing indicated that the film and hydrocolloid dressings produced greater wound contraction than the hydrogel and no dressing on days 7 and 10. Film, hydrogel, and hydrocolloid dressings also resulted in greater wound contraction than the control on day 14. Hydrocolloid dressings produced smaller measures of color and greater measures of luminance than no dressing on day 7. Film, hydrogel, and hydrocolloid dressings also resulted in smaller measures of color and greater measures of luminance compared with no dressing on days 10 and 14.

CONCLUSIONS

When compared with the control (no dressing), the film, hydrogel, and hydrocolloid occlusive dressings were associated with a faster healing rate of partial-thickness abrasions across time measured by wound contraction, color, and luminance. Overall, these data indicate that occlusive dressings were more effective in healing than no dressing was.

Formation of Cartilage In Vivo with Immobilized Autologous Rabbit Auricular Cultured Chondrocytes in Collagen Matrices

BACKGROUND

The availability of generated cartilage de novo is one of the needs of reconstructive surgery. In this study, the authors constructed a matrix formed by autologous immobilized chondrocytes using collagen gel as a scaffold. Furthermore, the ability of these matrices to engraft and generate new cartilage was examined.

METHODS

Biopsy specimens of elastic cartilage were surgically obtained from the ears of eight New Zealand White rabbits. After collagenase II digestion of cartilage, chondrocytes were isolated and propagated in culture medium. Chondrocytes were immobilized into bovine collagen lattices and implanted, replacing pieces of removed native cartilage. Five weeks after implantation, the rabbits were killed and the ears were examined macroscopically and analyzed by means of histochemical methods.

RESULTS

The results show the formation of new cartilage from implanted lattices with chondrocytes. Gross analysis of the ears shows similarities in appearance, consistency, texture, and histology between native and new cartilage. Fluorescence of the nucleus from bisbenzimide-labeled chondrocytes was detected in newly formed tissue, pointing out its in vitro culture origin. No signs of an inflammatory reaction attributable to implants were found in either the control or the chondrocyte lattices.

CONCLUSION

The authors suggest that this approach is of value for future clinical use.

The cleansing of superficial traumatic wounds

Patients with skin injuries account for 15% of accident and emergency (A&E) admissions (Leaman, 1991). Although there is evidence to suggest that wound cleansing is not always necessary (Thomlinson, 1987), no diagnostic test exists to allow healthcare practitioners to identify whether the bacterial load in the wound is capable of causing infection (Chrisholm, 1992). For this reason, all wounds in A&E should undergo some form of cleansing to decrease the bacterial inoculum in the wound to levels that can be managed by host defences (Chrisholm, 1992). Heyworth (1997) postulates that successful management of the contaminated wound must remove contaminants while inflicting minimal injury to tissue. This article reviews the research on the preparation and cleansing of superficial lacerations. Wound closure and indications for oral antibiotics will not be discussed.

Extracellular matrix contraction by fibroblasts: peptide promoters and second messengers

Cells contracting connective tissue matrices generate tractional forces in tissues. Studies of fibroblast contraction, using collagen gels in an in vitro model, demonstrate that it involves the actin cytoskeleton, specific extracellular matrix receptors and requires stimulation by exogenous promoters. Fibroblast contraction is stimulated by factors released by platelets and potentially secreted within the contracting tissue. Endothelial cells secrete a potent promoter of fibroblast contraction which has been identified as endothelin 1. The pathway through which fibroblast contraction is stimulated appears to require activation of protein kinase C. Tumor cells can also secrete endothelin. These mechanisms may be relevant to tumor progression.

The wound environment as a regulator of fibroblast phenotype

Fibroblasts are fundamental to successful wound healing. We hypothesized that the induction and regulation of various fibroblast functions (proliferation, collagen synthesis, and remodeling) are determined by the wound environment. We examined the effect of wound fluid (WF), as a reflection of the wound environment, on the phenotypic expression of normal dermal (NF) and wound-harvested fibroblasts (WHF). WF and WHF were obtained from implanted polyvinyl alcohol sponges in 10-day-old wounds. NF and WHF were used between one and three passages. Proliferative function was assayed in a microculture system using serum stimulation (n = 12). The proliferative response of both NF and WHF to serum was significantly reduced by the addition of 20% WF (17,261 +/- 1231 cpm vs 2704 +/- 1215 cpm for NF, P less than 0.05; and 15,391 +/- 3735 cpm vs 1701 +/- 816 cpm for WHF, P less than 0.05 in serum and WF, respectively). Total protein synthesis (measured by [3H]proline incorporation) was equal in both fibroblast types; however, the relative collagen synthesis (collagenase-digestible fraction) was markedly different (2.2 +/- 0.9% for NF vs 11.4 +/- 2% for WHF, P less than 0.05). Addition of WF markedly enhanced NF collagen synthesis to 9.4 +/- 2%, but had no effect on WHF. Mechanical and remodeling functions were assayed using fibroblast-populated collagen lattices. In serum, WHF contracted the lattices faster than NF (499 +/- 14 mm2 vs 770 +/- 30 mm2 at 24 hr, P less than 0.05, and 301 +/- 18 mm2 vs 540 +/- 21 mm2 at 72 hr, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)