ObjectiveTo observe the effects of endovascular radiation (ER) on the proliferation and apoptosis of medial smooth muscle cells (SMC) and to discuss the possible mechanisms of radiation in the prevention of vascular restenosis (RS) in rabbits after carotid endarterectomy (CEA).MethodsForty rabbits undergoing CEA were randomly divided into four groups (each group=10) and given a radiation dose of 0, 10, 20 and 40 Gy 32P respectively. Rabbits were killed on the 3rd, 7th, 14th, 28th and 56th day after operation. The specimens were collected and histopathologic examinations were done.ResultsProliferation apparently occurred in the intima and media of carotid the lumen became narrow in the control group on the 14 th, 28 th and 56 th day after operation. While in the radiation groups, proliferation was apparently suppressed and the lumen was much less narrowed (P＜0.05). The apoptosis rate of SMCs and PCNA positive cells increased on the 3rd day after operation and reached the peak on the 7th day. There was statistical difference between the ER groups and control group (P＜0.01). The effects were much more evident in 20 Gy and 40 Gy groups compared with 10 Gy group (P＜0.01).ConclusionER may prevent RS by suppressing SMC proliferation and migration as well as inducing SMC apoptosis. The effects are positively correlated with radiation doses. SMC proliferation and apoptosis occur in the early period after balloon injury, while hyperplasia of intima and medial happens later.
Objective To study the cellular biocompatibility, adhesion and proliferation of endothelial outgrowth cells (EOCs) isolated and expanded from rabbit peripheral blood cultured with aligned poly-L-lactic acid (PLLA) nanofibrous scaffolds in vitro so as to provide a basis for the applications of scaffolds biomaterials in tissue repair. Methods Nanofibrous scaffolds of PLLA by electrostatic spinning were modified by hypothermal plasmas body and type Ⅰ collagen was coated onto the materials physically. In vitro, EOCs were cultured on the modified PLLA scaffold. Adhesion and proliferation were surveyed and morphological changes and biocompatibility of seeding cells on PLLA scaffold were observed by growth curves of the cells, fluorescent microscope and scanning electron microscope respectively. Results Fibers with diameters ranging from 300 nm to 400 nm were included in the nanofibrous scaffolds, whose porosities were more than 90%. Absorbance (A) of each scaffold increased gradually after EOCs grew in the absence or presence of random, aligned, or super-aligned PLLA nanofibrous scaffold. Although there was no detectable effect of the random PLLA scaffold on the growth EOCs (Pgt;0.05), both aligned and super-aligned PLLA nanofibrous scaffold had significantly enhanced their growth since the 5th day (P＜0.05). The rates of adhesion in both aligned and super-aligned PLLA nanofibrous scaffold were significantly higher than those of random PLLA scaffold after 12 h and 24 h incubation (P＜0.01). The rates of proliferation after 1 d, 3 d and 7 d incubation in aligned and super-aligned PLLA nanofibrous scaffold were significantly higher than those of random PLLA nanofibrous scaffold (P＜0.05, P＜0.01). EOCs grew well with PLLA scaffold, yet confused and disorderly in random nanofibers. EOCs could attach, extend and proliferate following fibrous orientation in aligned and super-aligned PLLA nanofibrous scaffold, in majority of the fibers were oriented along the longitudinal axis so that a unique aligned topography was formed. Especially super-aligned PLLA nanofibrous had advantageous to keep well on cell morphology. Conclusion EOCs are ideal seeding cells for tissue engineering. EOCs can be adhered well to aligned and super-aligned PLLA nanofibrous scaffold and proliferate, keep well on cell morphology. So this type of PLLA nanofibrous scallfold is proposed to be an optimal candidate material for EOCs transplantation in tissue repair.
Objective To observe the adhesion and prol iferation of late endothel ial progenitor cells (EPCs) planted on nanoporous PLLA scaffold in vitro and to provide a new approach that optimizes tissue engineered material. Methods Male and female New Zealand rabbits (weight 2.5-3.0 kg) were used. Isolated late EPCs from rabbit peri pheral blood were cultured. Electrostatic spinning technique was adopted to prepare misal igned nanofibers, al igned nanofibers and super-al igned nanofibers, and low temperature plasma technique was appl ied to prepare misal igned membrane, al igned membrane and super-al igned membrane. After being divided into group A (cells only), B (misal igned membrane), C (normal membrane), D (al igned membrane) and E (super-al igned membrane), the primary late EPCs (1 × 105/mL) werecultured on scaffolds and MTT method was used to detect cell prol iferation abil ity at 3, 5, 7, 9, 11, 13, 15 and 17 days afterculture. After being divided into group A (misal igned membrane), B (normal membrane), C (al igned membrane) and D (superal igned membrane), precipitation method was appl ied to detect cell adhesion rate at 4, 12 and 24 hours after compound culture, and the morphologic changes of cells were observed at 4, 24 and 72 hours after compound culture. Results Fiber diameters in nanofibrous PLLA scaffolds were 300-400 nm, with a porosity rate of above 90%. At 3, 5, 7, 9, 11, 13, 15 and 17 days after culture, A value of each group was increased with time and the cells in each group grew well, showing there was no significant difference between group A and group B at each time point (P gt; 0.05 ); during the period of 7-15 days after culture, the difference between groups C, D and E and groups A and B was significant (P lt; 0.05). At 4 hours after compound culture, the adhesion rate of group A was superior to that of groups B, C and D (P lt; 0.05); at 12 and 24 hours after compound culture, the adhesion rate of groups B, C and D was remarkably higher than that of group A (P lt; 0.05); significant difference was noted in each group between the time point of 4 hours and the time point of 12 and 24 hours after compound culture (P lt; 0.05), but no significant difference between 12 hours and 24 hours was detected (P gt; 0.05). Morphology observation demonstrated that cells grew well on the scaffolds, the cells in groups A and B grew sporadically and disorderly, while the cells in groups C and D attached and al igned along fiber and prol iferated, with an excretion of ECM. Group D was better at maintaining cell morphology. Conclusion Al igned and superal igned nanofibers of PLLA scaffold can promote the adhesion and prol iferation of seed cells on the scaffold and maintain good cell morphology, which is an appropriate candidate scaffold material for blood vessel tissue engineering. Late EPCs is an ideal cell source for blood vessel tissue engineering.