Time characteristics of apoptosis and proliferate in rabbit remodeling process of vein grafting

Abstract

Objective Research transplanted vein remodeling time characteristic of the level of apoptosis and proliferation in the process. Methods Pure New Zealand big-eared white rabbit to 42 health to establish the rabbit model of external jugular vein carotid artery bypass grafting. It divided into 7 groups, respectively in the preoperative and postoperative day 1, 3, 7, 14, 28 days and 90 days after remove transplanted vein, and the degree of stenosis, proliferating cell nuclear antigen (PCNA) protein levels, apoptosis, and transmission electron microscopy (SEM) and other related testing. Results (1) Morphological observation: Intimal thickness was found to have decreased slightly 1 day after surgery [(1.5±0.3) μm], compared with normal control group [(4.6±0.8) μm], with significant difference (t=8.778, P=0.000), group 3rd days postoperatively [(4.6±0.7) μm], compared with normal control group differences insignificant (t=0.027, P=0.979), postoperative 7th days group [(19.0±2.8) μm, t=-12.114, P=0.000], 14th days after surgery group [(36.2±5.8) μm, t=-13.229, P=0.000], 28th days after group [(67.2±4.6) μm, t=-32.842, P=0.000], in 90th days group [(95.0±6.8) μm, t=-32.322, P=0.000], were higher than normal vein group, with significant difference; Membrane + outer membrane thickness: normal vein group was (6.6±0.8) μm, postoperative 1rd day group (8.8±1.2) μm (t=-3.737, P=0.005), group 3rd days postoperatively (16.2±2.1) μm (t=-10.471, P=0.000), in 7th days group (46.2±6.1) μm (t=-15.755, P=0.000), 14th days after surgery group (64.0±6.1) μm (t=-22.871, P=0.000), 28th days after group (126.1±6.4) μm (t=-45.409, P=0.000), 90th days after group (132.4±11.0) μm (t=-27.951, P=0.000), were higher than in normal control group, significant difference; (2) Western blotting analysis: The grayscale ratio of the band of interest to the internal reference band demonstrated that PCNA expression had decreased 1 day after surgery (33.4±3.7)%, for the normal control group (42.2±2.6)%, with significant difference (t=4.770, P=0.000), group 3 days postoperatively (56.3±3.8)% (t=8.778, P=0.000), higher than the control group, with significant difference, set up to 7 days after peak (79.7±8.3)% (t=-10.564, P=0.000), significantly higher than control group, postoperative 1 day, 3 days group, with significant difference, and gradually declining thereafter, for the 14 days after surgery (72.8±3.1)% (t=-18.537, P=0.000), 28 days after surgery (60.6±5.4)% (t=-7.527, P=0.000), and 90 days after surgery (48.0±3.8)% (t=-3.083, P=0.013), all higher than normal control group, with significant difference, and no unit of measure; (3) Immunohistochemistry: The percentage of PCNA-positive cells in control group was (6.25±0.90)%, which decreased slightly to (4.96±0.70)%1 day following surgery (t=2.755, P=0.021). By the 7th day, this value had peaked (32.70±3.10)% (t=-20.101, P=0.000), and gradually decreased after this point, no unit of measure. (4) TdT-mediated dUTP nick end labeling (TUNEL) apoptosis assay: A small number of apoptotic cells were observed in control group vein samples (1.36±0.20)%. The rate of apoptosiswas higheston the1st day following surgery (18.61±1.50)% (t=-27.873, P=0.000), and had decreasedby 3rd day (7.16±0.50)% (t=-26.251, P=0.000), reaching its lowest level on the 7th day (1.98±0.40)% (t=-3.402, P=0.011) and subsequently remaininglow. The percentage of apoptotic cells on days 14, 28, and 90 after surgery were (4.37±0.70)% (t=-10.122, P=0.000), (6.18±0.90)% (t=-12.839, P=0.000) and (6.56±1.20)% (t=-10.497, P=0.000), respectively, no unit of measure. Conclusion 1 day after venous transplantation to 3 days postoperatively, apoptosis level is higher; 7 days after proliferation level is higher. Key words: Proliferating cell nuclear antigen; Vein grafts; Restenosis