Objective To investigate the effect of cryopreservation (CP) on the expression of connective tissue growth factor (CTGF) in the renal tubular epithel ial cells. Methods A total of 40 male Wistar rats (weighing 230-250 g) were used in this study. En bloc removal with in situ cooling both kidneys and hypertonic citrate adenine preservation solution were adopted. The rat kidney was be preserved 0, 12, 24, 36 and 48 hours at 0-4℃ (n=8), respectively. The expression of CTGF of renal tubularepithel ial cells was detected by using immunohistochemistry and in situ hybridization analysis. Results The expression of CTGF was less in CP 0 hour group and CP 12 hours group, the positive unit (PU) values of CTGF protein were 5.91 ± 2.30 and 5.57 ± 2.40 (P gt; 0.05), respectively, and the PU values of CTGF mRNA were 6.24 ± 2.79 and 6.51 ± 2.43 (P gt; 0.05), respectively. The PU values of CTGF protein increased at CP 24 hours group (10.25 ± 2.92), CP 36 hours group (14.31 ± 2.83) and CP 48 hours group (18.11 ± 3.94, P lt; 0.05), respectively, and the PU values of CTGF mRNA increased at CP 24 hours group (15.24 ± 3.95), CP 36 hours group (19.20 ± 4.73) and CP 48 hours group (23.09 ± 4.40, P lt; 0.05), respectively; showing significant differences when compared with CP 0 hour group and CP 12 hours group (P lt; 0.05). Conclusion CTGF expression may increase with severe cold ischemia injury, and might play an important role in regeneration and repair of renal tubular epithel ial cell injury.
In order to repair cartilage defect in joint with transplantation of cryopreserved homologous embryonic periosteum, 30 rabbits were used and divided into two groups. A 4 mm x 7 mm whole thickness cartilage defect was made in the patellar groove of femur of each rabbit. The homologous embryonic rabbit skull periosteum (ERSP), preserved in two-step freezing schedule, was transplanted onto the cartilage defect of joints of one group and autogenous periosteal graft was done in the joint defect of the other group. The knees were not immobilized, following operation and 16 weeks later, the newly formed tissue in the defects were assessed by gross observation, histochemical examination and biochemical analysis. The results showed that new hyaline-like cartilage was formed in the cryopreserved ERSP grafted knee, and had no significant difference from that of the knee receiving autogenous periosteal graft, but had significant difference from that of the fresh ERSP grafted knee and the non-grafted knee. Furthermore, the new hyaline-like cartilage had the biochemical characteristics of a fibrous cartilage. The conclusion was that this method might be feasible to repair articular cartilage defects.
Abstract: Objective To investigate the influence of cryopreservation on cellular viability of latepregnancy fetal valved allografts in human. Methods The fetal valved allografts with gestational ages ranged from 24 to 40 weeks were sterilely procured within 6 hours after brain death. Each sample was bisected into control group and experiment group. The cellular viability of control group was directly tested and that of experiment group was examined after being storaged in liquid nitrogen for a week through a programmed frozen procedure. The light microscopy, tissue culture and Methylthiazol tetrazolium assay (MTT assay) were used to determine the cellular viability. Results Twelve latepregnancy fetal valved aortic allografts were procured. Light microscopy showed the integrity of the basic structure of the thawed aorta, the normal structure of the collagen and elastic fibers, with part of vascular endothelium lost. There were lots of cells deriving from both groups,but the cellular growing rate of the experiment group was relatively slower. At 490 nm, MTT assay valve of control group was 0.442±0.046, and that of experiment group was 0.424±0.041. The difference between two groups failed to statistically significance(t=1.617, P=0.328). Conclusion There were viable cells in latepregnancy fetal valved allografts after cryopreservation.
Objective To investigate the possibility of establishing the human bone marrow mesenchymal stem cells (hMSCs) bank as to provide an alternative source for the seed cells of tissue engineering. Methods The cell surface antigensof the purified, expanded hMSCs and the ones following cryopreservation were detected by flow cytometry, cultured in a special medium to induce the ostoegenic and chondrocytic- differentiation. Morphology was studied by light and electronic microscopes. The detection of alkaline phosphatase, collagen type Ⅰ, osteocalcin, and collagen type Ⅱ were also performed by immunochemistry and molecular biology.Results The phenotype and expansion possibility of hMSCs after cryopreservation were remained. It could expand for 10 generations. The doubling time was 40 h.Conclusion The bank of hMSCs is inipiently established and can provide eligible seed cells for tissue engineering.
Objective To investigate an effect of differenttemperature cryopreservation of the two-step freezing method on the Schwann cell biological activity in the peripheral nerve of the rat. Methods Eighty femaleSD rats were randomly divided into 8 groups of 10 rats each. One was the control group and 7 were the experimental groups. Two 2-cm-long sciatic nerve segments were respectively taken from both legs of each rat. In the control group, the sciatic nerve segments did not undergo the treatment of cryopreservation; however, in the 7 experimental groups, the sciatic nerve segments respectively underwent the different temperature cryopreservation of the twostep freezing method at -20℃, -30℃, -40℃, -50℃, -60℃, -70℃ and -80℃. The sciatic nerve segments were cryopreserved for 2 hours，and then placed into the liquid nigrtrogen at -196℃. After 48 hours of storage，the nerve segments werethawed quickly in the 37℃ water bath box for 1 minute. Then, the sciatic nerve segments each group were harvested. The cells of the sciatic nerve were incubated with Calcein-AM for 15 minutes. The average fluorescence intensity of the cells was measured by the flow cytometry. The nerve fibers were also incubated with Calcein-AM for 15 minutes. The fluorescence intensity of the cells was analyzed by the confocal fluorescence microscope. The Schwann cell biological activity intensity was measured. Results The fluorescence intensity in the -40℃ group was the best and the Schwann cell biological activity in this group was thebest among all the groups（P＜0.01）. The fluorescence intensity in the 8 groups measured by the flow cytometry was as follows：242.522 0±9.568 4 in the control group，168.677 0±10.207 0 in the -20 ℃ group，214.992 0±8.329 1 in the -30 ℃ group，235.526 0±9.280 5 in the -40 ℃ group，222.434 0±8.515 5 in the -50 ℃ group，217.409 0±9.515 7 inthe -60 ℃ group，132.376 0±13.459 7 in the -70 ℃ group， and 108.132 0±16.033 1 in the -80 ℃ group. The fluorescence intensity detected by the confocal fluorescence microscope was as follows：143.700 0±5.567 8 in the control group，119.700 0±5.161 5 in the -20 ℃ group，121.300 0±4.347 4 in the -30 ℃ group，700 0±5.012 2 in the -40 ℃ group，121.000 0±4.546 1 in the -50 ℃ group，118.400 0±4.9261 in the -60 ℃ group，81.200 0±5.116 4in the -70 ℃ group，and 79. 000 0±5.716 4 in the -80 ℃ group. Conclusion The Schwann cell biological activity treated by the two-step freezing methodcan be preserved and the activity is cryopreserved best at -40 ℃.
Objective To observe the configuration and viability of full thickness human fetal retina after short-, mid- and long-term preservation. Methods Twenty-two full thickness human fetal retinae of gestational age of 12-24 weeks were coated by glutin and cut into 88 pieces, and then preserved in Ames' solution, DX solution, -80℃ refrigerator or under cryopreservation condition. The cell viability of retinal neuroepithelial layer was determined by trypan blue staining, retinal configuration was determined by light microscope and electromicroscope. Results The viability of neuroepithelial layer was (94.79plusmn;2.85) % in fresh fetal retina, gt;80% in Ames' solution within 4 hours, and gt;77% in DX solution within 2 days. There was no significant difference between those solution-preservations and the fresh fetal. In -80℃ refrigerator, the viability was (65.83plusmn;5.06)% after 7 days, and then dropped to (57.54plusmn;16.18)% at the end of the first month. Under the cryopreservation condition, the viability was (69.46plusmn;9.31)% at the end of first month. Light and transmission electron microscopy had not deteced any abnormals in the full thickness human fetal retina preserved in Ames' solution within 2 hours, but showed clear retinal layers with bigger intercellular space after preserved in DX solution for 2 days, in -80℃ refrigerator for 7 days and under cryopreservation condition for 1 month. Conclusion Ames' solution and DX solution can preserve good viability and configuration of full thickness human fetal retina in a certain time period.
OBJECTIVE: To investigate the repairing effect of transplantation of allogeneic fetal bone in combination with a covering cryopreserved periosteal allograft to bone defect. METHODS: Twenty Long-eared white male rabbits were chosen as experimental model of bilateral 12 mm combined bony and periosteal radial defect. Cryopreserved allograft periosteum with allogeneic fetal bone were implanted in the left defect as experimental side and fetal bone was simply transplanted in the right defect as control side. Bone repair process in the two groups were compared by macroscopy, microscopy, roentgenograms and the contents of calcium and phosphate in the defect area at 2, 4, 8 and 12 weeks after transplantation. RESULTS: There was significant statistic difference in the contents of calcium and phosphate between the experimental and control sides at 4, 8 and 12 weeks after transplantation (P lt; 0.05). With time passing by, the contents of calcium and phosphate have the increasing trends. In the experimental group, lamella bone was seen and medullary canal recanalized at 8 weeks postoperatively. The histological section showed the bone lacuna and lamella bone were formed. CONCLUSION: It suggests that allogeneic fetal bone in combination with a covering cryopreserved periosteal allograft can promote bone repair, and allogeneic fetal bone is excellent bone substitute.
Abstract In order to determine the fasibility of reestablishment of circulation with cryopreserved microvenous allografts (1.0～1.4mm in diameter), 40 rabbits were divided into 2 groups. In the control group, the fresh autografts were used. In the experimental group, 20 rabbitsfemoral vein segments were treated by a two-step freezing procedure. After stored in liquid nitrogen for 48 hours, the segments were implanted into the femoral veins as allografts. The histological as well as the pathological studies were performed with light and electron microscope, and its patency was determined by angiography. The results showed that the preservation of vein was generally good. The rejective response was weak. The patency rates of 1 week and 12 weeks were 90% and 85% respectively, and there was no significant difference with that of the allogenic fresh autografts (Pgt;0.05). It was suggested that clinical use of cryoperserved allogenic microvein grafts instead of fresh autografts was possible.
OBJECTIVE: To investigate a cryophylactic agent (CPA) to protect tissue engineered tendon (TET) in deep low temperature. METHODS: Sixty-four BALB/C inbred nude mice were chosen, which included 4 as blank control group, left sides of 60 as experimental group and their right sides as control group. Transformed human embryonic tendon cells of the 54th passage and artificial materials of carbon fiber (CF) and polyglycolic acid (PGA) were co-cultured in vitro to construct TET. TET was frozen in liquid nitrogen with four kinds of CPA (groups A, B, C, and D) for 2 months. They were thawed quickly and transplanted into hind limbs of nude mice to repair the defects of Achilles tendon, which was 5 mm in length and 65.7% of total Achilles tendon. In control group, no cryopreservation treatment was taken. The morphological, histological, ultrastructure, and immunohistochemistry examinations were made and short tandem repeat loci were detected 2, 4, 6, 8, and 12 weeks later. RESULTS: In the experimental group, the morphological properties of tendon cells resumed gradually and the capability of synthesizing collagen enhanced by degrees. Tendon cells survived and could secret type I collagen and there was less difference between experimental and control groups 12 weeks after transplantation. In group A, vacuole in mitochondrion of tendon cell decreased, tendon cell arranged in order and abundant collagen fibers were found and linked. CONCLUSION: The cryopreservation agent in group A can protect TET in deep low temperature.
Objective To summarize the experience of l iving donor l iver transplantation using cryopreserved il iac vein for middle hepatic vein reconstruction. Methods Between July 2006 and June 2009, right l iver transplantation without middle hepatic vein was performed in 37 cases of 85 patients undergoing l iving donor l iver transplantation; of 37 cases, 30 received middle hepatic vein reconstruction using cryopreserved il iac vein. There were 27 males and 3 females, aged from 10 to 57 years (median, 44 years). Thirty cases included 11 hepatocellular carcinoma, 10 hepatic cirrhosis, 2 Wilson’ sdisease, 1 cholangiocarcinoma, 1 hepatoblastoma, 1 congenital hepatic fibrosis, 1 chronic severe hepatitis, and 1 congenital bil iary atresia. Il iac veins harvested from donors were put into 0-4℃ mixed antibiotics sal ine and transported to the operating room. The il iac veins were trimmed, placed into sterile bags (containing RMPI 1640 + 20% DMSO + 10% calf protein solution) and frozen at —70 . In l iving donor l iver transplantation process, the veins were melt and used for middle hepatic vein reconstruction. After operation, the patency of veins was monitored by regular Doppler ultrasound examination or enhanced CT for 3 months. Results In 30 patients, 30 il iac veins were used. The average cryopreserve time was 14 days (range, 3-44 days). Anastomosis were all successful; after cryopreservation, the blood vessels texture and elasticity were fit for surgery. No easily tearing or severe suture bleeding was observed. In 30 patients, 6 had segment V veins reconstruction; 3 had segment VIII; and 21 had both segments V and VIII. The patency rate of reconstructed vessels was 93% at 1 week, 90% at 2 weeks, 90% at 1 month, and 67% at 3 months. No serious compl ication was observed in donors. The prognosis was good with no small-for-size syndrome. Conclusion Cryopreserved il iac vein is an ideal material for the right hepatic l iving donor l iver transplantation in the reconstruction of middle hepatic vein.