Objective To investigate the feasibility oftissue engineered intervertebral disc for regeneration of discs. Methods A three-dimensional porous poly(L-lactic-co-glycolic acid) (PLGA) scaffold was fabricated by temperature induced phase separation method. Human fetal disc cells were isolated and cultured in vitro. The disc cells labeledwith a PKH-26 fluorescent dye were seeded into a threedimensional porous scaffold. The proliferation of disc cells with PKH-26 fluorescent labels was assessed by using MTT uptake, laser fluorescence microscopy and SEM. Results Human fetal disc cells displayed a polygonal shape in primary monolayer culture. A regular arrangement and microtubules orientationstructure scaffold with 50-300 μm in diameter was fabricated by thermal-induced phase separation technique. MTT uptake and fluorescent microscopy examination indicated that the seeded disc cells were viable and showed proliferation activity within a porous scaffold. Conclusion The above findings support potential applications of tissue engineered disc in treatment of disc degenerative diseases.
Objective To prepare a self-made compound, hemostatic jelly with polylactic acid(PLA), which has the hemostatic and absorbable effect on injured cancellous bone. Methods Two bone defects of 5 mm in diameter and 4 mm in depth were subjected on 20 health rabbits by drilling through their either outside plate of the iliac, and were filled with hemostatic jelly(group A), bone wax(group B) and blank(group C) respectively. Hemostasis were observed and recorded after 1 and 10 minutes. Five specimens were harvested at 2, 4, 8 and 12 weeks postoperatively for histological observation. Results ① Hemostatic effect: Bleeding of injured spongy bone stopped within 10 minutes after the treatment of hemostatic jelly and bone wax, but bleeding of balnk did not stop. Hemostatic jelly and bone wax adhered to bone defects firmly within 10 minutes was after the treatment. ② Absorbable effect: Hemostatic jelly and bone defects have not changed visibly in the first 2 weeks. With histological observation 4 to 8 weeks after the operation, hemastatic jelly was absorbed gradually and replaced by osteogenous tissue. It was absorbed completely after 8 to 12 weeks. Bone wax was not absorbed after 12 weeks, no new bone tissue was observed at bone wax area. The blank was replaced by connective tissue and osteogenous tissue partially after 12 weeks. Conclusion The compound hemostatic jelly manifests both hemostatic and absorbable effects on injured cancellous bone and may substitute for bone wax in clinical application.
Objective To determine the incidence of vitamin B1 deficiency in critically ill patients, to compare vitamin B1 levels between septic and non-septic patients, and to explore the relationship between vitamin B1 levels and lactate levels. Methods Using a retrospective study method, critically ill patients admitted to the Department of Intensive Care of Nanjing Drum Tower Hospital from February 2022 to November 2022 were included in the study, and the patients were divided into sepsis and non-sepsis groups according to the admission diagnosis, and the differences in the vitamin B1 levels of the patients between the two groups were analyzed, as well as the correlation between the vitamin B1 levels and the lactic acid levels. Results There was a significant difference in serum vitamin B1 levels between the sepsis patients and the non-sepsis patients [(1.6±0.3)ng/mL vs. (2.1±0.2)ng/mL, P=0. 009]. For all patients, there was no correlation between vitamin B1 levels and lactate levels. But when the patient was in a hyperlactate state (lactate level ≥2 mmol/L), vitamin B1 levels were significantly negatively correlated with lactate levels (r=–0. 229, P=0. 004). Conclusions Vitamin B1 deficiency is prevalent in critically ill patients and is strongly correlated with whether or not the patient is septic. Vitamin B1 levels are significantly and negatively correlated with lactate levels when the patient's lactate level is ≥2 mmol/L.
OBJECTIVE To confirm membrane-guided tissue regeneration in the healing course of segmental bone defects and study the mechanism. METHODS Segmental, 1 cm osteoperiosteal defects were produced in both radii of 12 rabbits. One side was covered with hydroxyapatite/polylactic acid(HA/PLA) membrane encapsulated as a tube. The contralateral side served as an untreated control. Healing courses were detected by radiographic and histologic examinations. RESULTS All control sides showed nonunion, whereas there were consistent healing pattern in test sides. CONCLUSION Membrane technique can promote bone regeneration.
Objective To investigate the feasibility of fetal liver cells for liver tissue engineering, the supporting function of poly L lactic acid (PLLA) scaffold for fetal liver cells and the effects of oncostatin M (OSM), nicotinamide (NA) and dimethyl sulfoxide(DMSO) on growth and hepatic differentiation. Methods After three dimensional PLLA scaffolds having a porous structure were prepared by using NH 4HCO 3 particle, fetal liver cells obtained from E14.5 C57BL/6CrSlc murine embryos were inoculated in the scaffolds. Cells were cultured in Williams’E medium with or without OSM, NA and DMSO for 30 days. Changes in cell number, liver-specific function, and cellular morphology were observed. Results When compared with in monolayer culture, cell number and albumin secretion increased obviously in three-dimensional PLLA. Alburmin secretion increased slightly in OSM group of monolayer culture, but increased obviously in OSM groupo of PLLA culture and in OSM/NA/DMSO group of both monlayer and PLLA cultures. Conclusion The three-dimensional PLLA scaffold is a good supporting material for the cultivation of tetal liver cells. OSM, NA and DMSO remarkaly stimulated maturation of hepatic parenchymal cells in vitro in terms of morphology and liver-specific function.
In order to find an ideal biological material to prevent peridural adhesion following laminectomy, 30 rabbits were used as animal model, in each of which 2 defects with a size of 1 cm x 0.5 cm were made following laminectomy of L3, L5 spine. One of the defects was covered extradurally with chitosan, gelatin foam or PLA membrane respectively, while the other defect was exposed as control. All of these animals were sacrificed on the 2nd, 4th, 6th, 8th and 10th week after operation, and the extradural fibrosis and adhesion of every animal were evaluated by gross observation and histological examinations. It was revealed that in the chitosan and PLA membrane groups, the extradural tissue was smooth without thickening and there was no fibrous proliferation or adhesion in the epidural cavity, and that in the chitosan group, the growth of fibroblast was restrained but the growth of the epithelial cells was promoted significantly, thus, wound healing was rapid. In the control group and gelatin foam group, obvious extradural fibrosis and adhesion were observed and the extradural space had almost disappeared. Therefore, it was concluded that the biodegradable PLA membrane and chitosan were both an ideal material in the prevention of postoperative epidural adhesion.
Objective To determine the ability of the polyactic acid glue (PLA-G) in preventing epidural adhesion after laminectomy. Methods Each of the 24 randomly selected rats was done laminectomyof L2 and L5. The PLA-G, which would change from liquid to solid when meets with serum, was used in the epidural site of L5 to become a half-solid membrane(the experimental group, EG). The PLA-G was not used in the same site of L2(the control group, CG) .The gross anatomical, histological, and microscopical evaluation were made 2，4，6，8，10 and 12 weeks after operation; electron microscope observation was also made on two rats 4 weeks after operation(both EG and CG). Results Obvious epidural space was observed between dura mater and scar tissue(ST), but no cells in the epidural space were observed inEG 2 weeks after operation. Corps of the red cells between dura mater and ST and proliferation of fibroblast cell(FB) were observed in CG 2 weeks after operation. Some remaining glue shiver in the epidural space with lightly increasing fibroblast and smooth dura mater were observed in EG 4 weeks after operation. However, fragile scar conglutinated with dura mater diffusely and more FB were observed in CG. From the 6th week to the 12th week, a potential interspace between scar and dura mater was observed and PLA glue was absorbed completely in EG. However, tougher scar, which was very difficult to dissect from dura mater and surrounding tissues, was observed. According to the fibroblast ultrastructure observation, bigger nucleus and more plentiful rough endoplasmic reticulum were observed in CG. Conclusion The PLA-G can effectively reduce the epidural scar and adhesion in animal experiment.
Objective To establish an animal model for repairing the sciatic nerve defect with a biodegradable poly D,L-lactic acid/nerve growth factor (PDLLA/NGF) that can control the release conduit in rats and to observe an effect of the conduit on the sciatic nerve regeneration. Methods The PDLLA conduit and the PDLLA/NGF-controlled release conduit (NGF 450 U per conduit) were madewith the solvent-volatilixation method. Forty male SD rats were randomly and equally divided into 4 groups. The middle segments (10 mm) of the sciatic nerves of the rats were excised and were then repaired with the sciatic nerve autograft(Group A), with the PDLLA conduit (Group B), with the PDLLA conduit and an injection of NGF (30 U) into the conduit (Group C), and with the PDLLA/NGF controlled-release conduit (Group D), respectively, with the 10-mm nerve defect left behind. Three months after operation, the morphologic parameters of the nerve regeneration were observed and evaluated under light microscope and electron microscope, and the image analysis was also made. Results Three months after operation, porous adherence between the conduit and the surrounding tissues could be observed. The conduit presented a partial biodegradation but still remainedintact in the outline and the proximal nerve regenerated through the conduit cavity. Based on the histological observation, the quantity, uniformity, and maturity of the nerve fiber regeneration in Groups A and D were better than those in Groups B and C. The image analysis indicated that there were no significant differences in the nerve fiber diameter, axon diameter or myelin thickness between Group A and Group D (P＞0.05). However, all the parameters in Groups A and D were better than those in Groups B and C (P＜0.05). Conclusion The PDLLA/NGF-controlled release conduit can effectively promote the sciatic nerve regeneration of rats. Its morphological index is similar to that of the nerve autograft.
Objective To investigate the effect of tissue engineering bone compounded in vitro by nanohydroxyapatite/collagen/ polylactic acid (nHAC/PLA) and recombinant human bone morphogenetic protein 2 (rhBMP-2) in repairing rabbit critical calvarial defects. Methods Forty eight New Zealand rabbits, weighting 2.0-2.5 kg, were made the models of critical cranial defects(15 mm in diameter) and divided into 4 groups randomly. Defects were repaired with autoflank bone in the positive control group; with no implant in the blank control group; with nHAC/PLA in the negative control; and with active nHAC/PLA(AnHAC/PLA) in the experimental group(the average quality of each AnHAC/PLA absorbed rhBMP-2 was 1.431 mg). The reapir results were observed through X-ray,HE dyeing and Masson’s trichrism dyeing after 8 and 16 weeks. Results The difference of bone formation was observed by X-ray block degree of skull defect area at 8 and 16 weeks. In the 8 th week and 16 th week, the radiopacities on cranial defect were 67.21%±2.06% and 86.48%±1.73% in the positive control group； 5.84%±1.92% and 9.48%±2.72% in the blank control group; 19.13%±2.51% and 35.67%±3.28% in the negative control group; and 58.84%±2.55% and 8561%±3.36% in the experimental group. There were significant differences between the negative control and the positive control group, and between the experimental group and the positive control group at 8 weeks(Plt;0.05) . There were significant differences between the negative control and blank group, and between the experiment and the blank group at 8 and 16 weeks(P＜0.05). The histology observation showed that the width of bone trabecula at 16 weeks was more than that at 8 weeks and bone defectwas full of bone tissue in positive control group. The bone defect was full of fibrous tissue at 8 and 16 weeks, and there was no new bone in the blank group. The bone defect was full of remnant material and fibrous tissue in the negative control group. The implanted area was replaced by the new bone at 8 weeks and the new bone was lamellar at 16 weeks in the experimental group; the residual material was less in defect area and there were more osteoblasts surrounding. Conclusion The nHAC/PLA is a good scaffoldmaterial of rhBMP-2 and AnHAC/PLA has agood ability in repairing bone defect. So it is hopeful to be applied in the clnical repair of large bone defect.
ObjectiveAdopting poly-L-lactic/glycolic acid (PLGA) and polyethylene glycol (PEG) as the material to fabricate PLGA/PEG electrospun polymer membrane by electrospinning technology. And to study its preventive effect on postoperative intraperitoneal adhesion of rat.MethodsPLGA and PEG were mixed at the ratio of 19∶1(M/M), then dissolved in organic solvent. The PLGA/PEG electrospun polymer membrane was prepared by electrospinning technology, and then the gross observation and scanning electron microscope observation were taken. Fifty-four Sprague Dawley rats (weighing, 180-200 g), were randomly divided into 3 groups. The rats in control group (n=6) were left intact. The rats in model group (n=24) and PLGA/PEG group (n=24) were treated with the method of mechanical injury of the cecal serosa in order to establish the intraperitoneal adhesion models; then the PLGA/PEG electrospun polymer membrane was used to cover the wound in PLGA/PEG group, but was not in the model group. The intraperitoneal adhesion in PLGA/PEG group and model group were observed at 3 days, 1 week, 2 weeks, and 8 weeks after operation, and the adhesion degree was assessed according to the self-generated standard. The degradation of PLGA/PEG electrospun polymer membrane was also observed in PLGA/PEG group. At each time point, the rats were harvested for histological observation. All the above indexes were compared with the control group.ResultsUsing the electrospinning technology, PLGA/PEG electrospun polymer membrane was prepared successfully. PLGA/PEG electrospun polymer membrane was white and opaque, with soft texture. Scanning electron microscopy observation showed that PLGA/PEG electrospun polymer membrane was mainly composed of disorderly staggered fibers, with microporous structure. All rats survived to the end of the experiment. Gross observation showed that PLGA/PEG electrospun polymer membrane gradually degraded after implantation in vivo, and the adhesion degree in PLGA/PEG group was significantly lower than that in model group (P<0.05), but it had not yet reached to the level of the control group (P<0.05). Histological observation showed that the proliferation of cecal fibrous connective tissue was slower in PLGA/PEG group than in model group, and adhesion severity significantly decreased, only with a small amount of inflammatory cell infiltration. Nevertheless, it was not up to the level of the control group.ConclusionPLGA/PEG electrospun polymer membrane can effectively prevent postoperative intraperitoneal adhesion of rat, and has good biodegradability.