To understand the reason of hyperpigmentation following full-thickness skin autograft, 54 guinea pigs were selected as skin autograft models. The changes of density of epidermal keratinocyte (KC) and the amount and distribution of melanin in the epidermal KC were observed by histological, histochemical and autoradiographic techniques. The results showed: (1) The histological changes of KC were in fact a wound-repair process; (2) The increased melanin in KC coordinated with "multi-overlapping screen" effect, a result of multiple layers of "supranuclear cap", was the direct cause of hyperpigmentation of the graft and (3) The hydrolytic disturbance of melanin in KC and the longer life span of the KC were probably the important reasons for the increase of melanin in the epidermis.
Objective To observe the effects of keratinocytes on proliferation and collagen secretion of fibroblasts. Methods The conditioned medium,collected from cultured keratinocytes, was added to the cultured fibroblasts as the tested groups(12.5％, 25% and 50％ groups) and DMEM as control group. The MTT, hydroxyproline coloricmetric method and flow cytometer were employed to measure the fibroblast proliferation, the collagen secretion andthe change of the cell cycle.Results In fibroblast proliferation, the absorbency(A) value of tested groups was significantly different from that of the control group (P＜0.01). A value increased as increasing concentration, there was statistically significant difference betweetheconcentrations of 25%,50% and the concentration of 12.5%(P＜0.01), but no statistically significant difference between the concentrations of 25% and 50%(P＞0.01). In collagen secretion, there was no statistically significant difference between the tested groups and the control group(P＞0.01), and between the tested groups(P＞0.01). In cell cycle, 50% of conditioned medium could make the fibroblast pass the limit of G1/S and S/G2 period, the cell rates of S,G2-M period increased. Conclusion The conditioned medium from keratinocytes can increase fibroblasts proliferation, have little effect on general collagen secretion.
Objective To investigate the outcome and histological changes of transplantation of acellular xeno-dermis combined with suspended keratinocytes.Methods Forty-two nude mice with full-thickness skin defect on the back were randomly divided into 2 groups, then acellular xeno-dermisand and suspended keratinocytes were adopted to cover the skin defect in the experimental group, pure suspended keratinocytes in the control group. The area of wound healing was calculated2, 3 and 5 weeks after transplantation, and the rates of wound contraction werealso calculated,and biopsy for histological examination was performed 3, 6and 12 weeks after transplantation. Results Compared with the experimental group,the control group showed delayed wound healing (P＜0.05), intensive wound contraction (P＜0.05), poor durability, elasticity, and cosmetic appearances as well asdisordered collagen fibers. In contrast, it was observed that the proliferationof collagen fibers was regularly organized, with no obvious acute immuno-rejection responses in the experimental group. Conclusion The composite transplantation of acellular xenodermis and suspended keratinocytes could promote the woundhealing with a satisfactory outcome.
Objective Dermal papillae cells are widely applied to reconstruction of tissue engineered hair foll icle and skin. To investigate the difference of the biological characteristics of dermal papillae cells cultured with keratinocyte medium (KM)and normal medium (NM), and to determin whether it is feasible for the reconstruction of tissue engineered hair foll icle using dermal papillae cells cultured in KM. Methods Scalp samples were obtained in rhytidectomy procedure. Dermal papillaes were isolated by two steps digestive treatment, then cultured with KM and NM in two groups. The time of dermal papillae adherence and cell outgrowth was recorded and the rate of dermal papillae adherence was determined after 5 days. As well as, the difference of cell morphology was observed through inverted phase contrast microscope. The maximum generations were determined in two groups and the cell sheets were observed by HE staining. In third-generation cells, the number of aggregates in every dish and the prol iferation by MTT were compared between two groups. Meanwhile, the expression of α-smooth muscle actin (α-SMA) and ALP were detected by immunofluorescence and specific staining in two groups. Results Dermal papillaes of KM group had a higher rate of adherence and fast outgrowth. The rates of adherence were 54.17% and 36.78% in KM group and in NM group, respectively. In KM group, cells adhered after 24 hours and outgrew after 64 hours. While, cells adhered after 48 hours and outgrew after 80 hours in NM group. The cells were bigger in NM group than in KM group. In third-generation cells, 3.06 ± 1.12 and 9.25 ± 1.73 aggregates formed in NM group and KM group, respectively, the difference was significant (P lt; 0.05). In addition, cells could form cell sheets which were muti-layers in KM group. Mostly 7 and 15 generations could been subcultured in NMgroup and KM group, respectively. The result of MTT indicated that cells prol iferated more actively in KM group; absorbance value of KM group was significantly higher than that of NM group after 7 days (P lt; 0.05). The positive of α-SMA were detected in the third-generation cells of both groups. Ocassionally a l ittle few cells expressed ALP with (987 ± 146) m2 positive area in the sixth-generation cells of NM group. However, the cells still expressed ALP with (8 757 ± 558) μm2 positive area in the fourteenthgeneration cells of KM group and the difference was significant (P lt; 0.05). Conclusion Cells proliferate actively and aggregate obviously and could been subcultured more generations in KM. Therefore, culturing dermal papillae cells with KM is feasible for the reconstruction of tissue engineered hair foll icle.
【Abstract】 Objective To observe the effects of Angelica dahurica extracts on the biological characteristics of human keratinocytes (KC) in vitro and to explore the possible mechanism in promoting wound healing. Methods HaCaT cells of passage 5 from KC were used during the experiment. Different concentrations (5 × 10-2, 5 × 10-3, 5 × 10-4, and 5 × 10-5 g/L) of Angelica dahurica extracts, which was obtained by 95% ethanol from Angelica dahurica raw material, were prepared by DMEM containing 0.25% fetal bovine serum (FBS). After the extracts at different concentrations were respectively used for KC culture for 5 days, the cell proliferation activities were detected by MTT, and DMEM containing 0.25% FBS served as the negative control. According to the cell proliferation activity, the optimal concentration was determined. KC was further treated with Angelica dahurica extracts of the optimal concentration (experimental group) or with DMEM containing 0.25% FBS (control group) for 48 hours. The cell cycle was tested by flow cytometry. Cyclin D1 and Caspase-3 mRNA levels were also detected by real-time fluorescent quantitative PCR technique. Results Angelica dahurica extracts at concentrations of 5 × 10-4, 5 × 10-3,and 5 × 10-2 g/L could significantly enhance KC proliferation, showing significant differences in absorbance (A) values compared with that of control group (P lt; 0.05) with an optimal concentration of 5 × 10-3 g/L. At this concentration, an increased percentage of S and G2/M phase cells and a decreased percentage of G0/G1 phase cells were detected, showing significant differences when compared with control group (P lt; 0.05). Real-time fluorescent quantitative PCR revealed that the cyclin D1 and Caspase-3 mRNA levels of experimental group was significantly down-regulated, showing significant differences when compared with control group (P lt; 0.05). Conclusion Angelica dahurica extracts can promote the proliferation of KC, accelerate the cell cycle of KC by down-regulating mRNA expressions of cyclin D1, and inhibit apoptosis by down-regulating mRNA expressions of Caspase-3. These effects might enhance the process of wound healing by expediting the process of epithelization.
OBJECTIVE: To fabricate artificial human skin with the tissue engineering methods. METHODS: The artificial epidermis and dermis were fabricated based on the successful achievements of culturing human keratinocytes(Kc) and fibroblasts (Fb) as well as fabrication of collagen lattice. It included: 1. Culture of epidermal keratinocytes and dermal fibroblasts: Kc isolated from adult foreskin by digestion of trypsin-dispase. Followed by comparison from aspects of proliferation, differentiation of the Kc, overgrowth of Fb and cost-benefits. 2. Fabrication of extracellular matrix sponge: collagen was extracted from skin by limited pepsin digestion, purified with primary and step salt fraction, and identified by SDS-PAGE. The matrix lattice was fabricated by freeze-dryer and cross-linked with glutaraldehyde, in which the collagen appeared white, fibrous, connected and formed pores with average dimension of 180 to 260 microns. 3. Fabrication artificial human skin: The artificial skin was fabricated by plating subcultured Kc and Fb separately into the lattice with certain cell density, cultured for one week or so under culture medium, then changed to air-liquid interface, and cultured for intervals. RESULTS: The artificial skin was composed of dermis and epidermis under light microscope. Epidermis of the skin consisted of Kc at various proliferation and differentiation stages, which proliferated and differentiated into basal cell layer, prickle cell layer, granular layer, and cornified layer. Conifilament not only increased in number, but also gathered into bundles. Keratohyalin granules at different development stages increased and became typical. The kinetic process of biochemistry of the skin was coincide with the changes on morphology. CONCLUSION: Tissue engineered skin equivalent has potential prospects in application of repairing skin defect with advantages of safe, effective and practical alternatives.
Objective To review the latest research progress on keratinocyte growth factor (KGF), to thoroughlyunderstand its basic characteristics and appl ication methods and to lay a sol id foundation for the research and development of new KGF medicines and improving the qual ity of skin substitutes. Methods Domestical and international l iteratures on KGFin recent years were extensively reviewed and analyzed. Results KGF was secreted by mesenchymal cells and its receptors were distributed in epithel ium to promote the prol iferation, migration and differentiation of epithel ial cell specifically, which closely related to the organ development, wound heal ing, tumorigenesis and immune reconstruction. Conclusion KGF can be used to improve wound heal ing and the performance of skin substitutes. However, the structure of KGF needs to be changed to el iminate its side effects and purify its promoting effect on epithel ial cell growth.
Objective To investigate the different influence of the expression levels of the epidermal growth factor (EGF) and the keratinocyte growth factor (KGF) after the unilateral phrenectomy in piglets. Methods Thirty-six piglets were divided into 3 groups according to their ages during the operation (10 d,30 d,50 d). In each group, 6 piglets underwent the left cervical phrenectomy and 6 piglets were used as the shamoperation controls. The expression levels of EGF and KGF were determined by the real time quantitative RT-PCR at 2 weeks after operation.Results The melting curves of RTPCR showed that there was a single peark at the temperature of 80.0, 84.5 and 89.0℃ of EGF,KGF and GAPDH, respectively. In the experimental group, the expression levels of EGF were 3.53±0.36 and 1.73±0.29, and the expression levels of KGF were 4.71±0.42 and 2.77±0.29 in thepiglets undergiong the operation at their ages of 10 d and 30 d.Compared with the control group,the expression levels of EGF (4.60±0.41，2.18±0.24) and KGF(6.05±0.42，3.58±0.31) showed that there was a significant decrease postoperatively in the piglets undergoing the operation at their ages of 10 d and 30 d（P＜0.05）. However, there was no significant change in the piglets undergoing the operation at their ages of 50 d（P＞0.05）. The expression levels of EGF and KGF were significantly decreased with the lung development of the piglets（P＜0.05）. Conclusion The unilateral phrenectomy performed in the piglets younger than 30 d may cause abnormity of the EGF and KGF expression levels. The piglets older than 50 d may not cause a significant influence.
Objective
To investigate the effects of heat injured keratinocytes (KC) supernatant on the expressions of collagen type I, collagen type III, and matrix metalloproteinase 1 (MMP-1) of dermal fibroblasts (Fb).
Methods
KC and Fb were isolated and cultured. Then the models of heat injured KC and Fb were reproduced in vitro, respectively. The heat injured and normal culture supernatant were collected respectively at 12 hours, and formulated as a 50% concentration of cell-conditioned medium. According to the culture medium, Fb at passage 3-5 was divided into 3 groups. Normal Fb was cultured with the conditioned medium containing 50% heat injured KC culture supernatant (group A), the conditioned medium containing 50% normal KC culture supernatant (group B), and DMEM (group C), respectively. The cells in 3 groups were collected at 24 hours. In addition， the cells in group A were collected at 0, 1, 2, 6, 12, 24, and 48 hours， respectively. Normal Fb was cultured with the conditioned medium containing 50% heat injured Fb culture supernatant. Then, the cells were collected at 0, 1, 2, 6, 12, 24, and 48 hours, respectively. The mRNA levels of the collagen type I, collagen type III, and MMP-1 of Fb were measured by real-time fluorescent quantitative PCR techniques.
Results
At 24 hours after cultured with supernatant of heat injured KC，mRNA relative expression levels of collagen type I, collagen type III, and MMP-1 in group A were significantly higher than those in groups B and C (P lt; 0.05). The mRNA relative expression levels of collagen type I, collagen type III, and MMP-1 in group A gradually increased with time going, showing significant differences between 0 hour and 2, 6, 12, 24, and 48 hours (P lt; 0.05); significant differences were found between different time points after 2 hours (P lt; 0.05). After Fb was treated with supernatant of heat injured Fb, the mRNA relative expression levels of MMP-1 gradually decreased with time going, showing significant differences between 0 hour and 1, 2, 6, 12, 24, and 24 hours (P lt; 0.05); after 2 hours of culture, significant differences were found among different time points (P lt; 0.05).
Conclusion
Heat injured KC supernatant may regulate the mRNA expressions of collagen type I, collagen type III, and MMP-1 of Fb.
OBJECTIVE: To investigate the selection and identification of human keratinocyte stem cells(KSC) in vitro. METHODS: According to the characteristics of KSC which can adhere to extracellular matrix very fast, we selected 3 groups of different time(5 minutes, 20 minutes and 60 minutes) and unselected as control group. And the cells were identified by monoclone antibody of beta 1-integrin and cytokeratin 19 (Ck19), then the image analysis was done. Furthermore we analyzed the cultured cells with flow cytometer(FCM) and observed the ultrastructure of the cell by transmission electron microscope(TEM). RESULTS: The cell clones formed in all groups after 10 to 14 days, while the cells of 5 minute group grew more slowly than those of the other groups, however, the clones of this group were bigger. The expression of beta 1-integrin and Ck19 were found in all groups. The positive rate of beta 1-integrin was significant difference between 5 minute group and the other groups (P lt; 0.05). And the expression of Ck19 was no significant difference between 5 minute group and 20 minute group(P gt; 0.05), and between 60 minute group and control group. But significant difference was observed between the former and the later groups(P lt; 0.05). The result of FCM showed that most cells of the 5 minute group lied in G1 period of cell cycle, which was different from those of the other groups. At the same time, the cells of 5 minute group were smaller and contained fewer organelles than those of the other groups. CONCLUSION: The above results demonstrate that the cells of 5 minute group have a slow cell cycle, characteristics of immaturity, and behaving like clonogenic cells in vitro. The cells have the general anticipated properties for KSC. So the KSC can be selected by rapid attachment to extracellular matrix and identified by monoclone antibody of beta 1-integrin and Ck19.
