Objective To study the advances in microcirculation after islets of Langerhans transplantation (ILT). Methods The literature in the recent years on the study of the relationship between ILT and microcirculation was reviewed. Results The process of angiogenesis and revascularization of the islet grafts was in progress within 1 week after transplantation, and was completed within 10-14 days after transplantation, exhibiting a microangioarchitecture similar to pancreatic islets in situ. The sequence of vascular intraislet cellular perfusion was from β cells outward to α-and δ-cell cortex, with the majority of α cells perfused before the majority of δ cells. Freely transplanted islet grafts were revascularized from the hostderived microvascular bed. The interstitial pressure in the islet transplants was markedly lower than the capillary pressure. There were clearly differences in microcirculation between syngeneic and xenogeneic islet grafts. The phenomena of microcirculation failure were observed in xenografts. The influential factors of microcirculation after ILT were ①culture temperature of isolated islets, ②cultured time and cryopreserved method of islets, ③blood glucose, ④immunosuppressive agents, ⑤angiogenesis factors. Conclusion Microvascularization of freely islet grafts is one of the essential requirements for successful engraftment, guaranteeing sufficient nutritional blood supply to the tissue and establishing blood drainage for adequate liberation of the endocrine hormones. Through the studies of the microcirculation after ILT, it is helpful to recognize the mechanism of the survival of islet grafts.
Objective To explore the effect of renal microcirculation following severity acute pancreatitis （SAP） on renal injury and to explore the protection effect of urokinase on them. Methods A total of 192 Wistar rats were randomized divided into normal control group， SAP group， and urokinase group， then rats of 3 groups were sub-divided into 2， 6， 12， and 24 hours group， each group enrolled 16 rats. Of the 16 rats in each subgroup， 8 rats underwent blood flow of renal test， other 8 rats were sacrificed to get blood samples and to perform histopathological examination. The rat models of SAP were established by retrograde injecting with 5% sodium taurocholate into the cholangiopancreatic duct. Radioactive biomicrosphere technique was used to measure the blood flow of renal， levels of plasma thromboxane B2（TXB2） and 6-keto-prostaglandin F1α （6-Keto-PGF1α） were tested by the TXB2 kit and 6-Keto-PGF1α kit， and histopa-thological changes of renal tissues were observed by using HE staining. Results Compared with normal control group at the same time point， the blood flow of renal were lower （P＜0.05）， activity ratio of TXB2 to 6-Keto-PGF1α were higher（P＜0.01）， and the histopathological injury were worse （P＜0.01） in rats of SAP group and urokinase group. Compared with SAP group， the blood flow of renal at 2， 6， and 12 hours in urokinase group were higher （P＜0.01）， the activity ratios of TXB2 to 6-Keto-PGF1α were lower （P＜0.01）， and the histopathological injury were lighter （P＜0.05） in all the 4 time points of urokinase group. Conclusions The renal microcirculation dysfunction and increase of activity ratio of TXB2 to 6-Keto-PGF1α may play an important role in renal injury following SAP in early stage. Urokinase can protect the renal from such injuries.
ObjectiveTo explore the effects of urinastatin(UTI) on microcirculation of extrapancreatic organs in rats with acute necrotizing pancreatitis(ANP). Methods A total of 48 rats were randomized into control group, ANP group and UTI group. The model of ANP was established by uniform injection of 5% sodium taurocholate solution under pancreatic capsule, only injection of normal saline in control group. Then the rats of UTI group were injected with UTI through the femoral vein, the rats of ANP group and control group were injected with normal saline. The blood flow of lung, kidney and distal small intestine was measured by radioactive biomicrosphere technique at 2 h and 6 h after ANP.ResultsCompared with the control group, the blood flow of lung, kidney and intestine was decreased significantly in the ANP group at the 2 h and 6 h after ANP （P＜0.05）, compared with the ANP group, the blood flow was increased significantly in UTI group （P＜0.05）. ConclusionMicrocirculation disorder is an important factor of the extrapancreatic organ damage in ANP, and UTI plays a protective role against microcirculation disorder of the extrapancreatic organ in ANP.
In order to study the influence of reperfusion following ischemia on microvesseles and microcirculation of skeletal muscle, unilateral hindlimbs of 16 rabbits were subjected to normothermic ischemia for 2 and 5 hours by tourniquet. After release of the tourniquet, microcirculation of the peritenon on dorsum of the foot was observed for 1 hours by intravital microscope. At 1 hour and 72 hours following reperfusion, the anterior tibia muscle biopsiy were taken and the specimens were subjected to light and electron microscopic examinations. It was found that after release of the tourniquet, in the limbs undergone 2 hours ischemia, there was immediate and well distributed reflow in the microvesseles of peritenon though a few aggregates of red cells and increase in the number of adherent leukocytes occured in some venules, and the microvesseles of the skeletal muscle only showed signs of minimal injury, the muscle fibers could survive in the limbs undergone 5 hours of ischemia, however, there was serious disturbance of microcirculation in theperitenon, which was characterized by "no reflow" in most area and there was signi ficant increase in the number of leukocytes adherent to venular endothelium, and the microvesseles of the skeletal muscle showed signs of severe injury, including remarkable swelling of the endothelial cell, disruption of the basement membrane and interstitial edema, and finally, most of the muscle fibers had necrosis occured. The results demonstrated that reperfusion following ischimia might result in microvascular injury and microcirculation disorder in the ischemic area. The degree of the injury and disorder depended on the duration of ischemic period, and was an important factor which determined the fate of the parenchymal cell.
The model of acut hemorrhagic necrotizing pancreatitis(AHNP)was produced by retrograde injection of 3% sodium taurocholate into the biliopancreatic duct.48rats with AHNP were treated with Tanshin by subcutaneous injection(100mg/100g body weight,q12h,tanshin group),48 rats with AHNP without any treatment as control(control group).The resule showed that in the control group,there were severe hemorrhage,necroses and the lesions of microvascular,the activity of pancreatic enzyme in serum increased significantly(Plt;0.01)at 6h,after 12h the activities of those pancreatic enzymes decreased gradually, the lesions of microvascular and histology were becoming severer.In the Tanshin group,at 24h the lesions of microvascular and histology of the pancreas were modified significantly (Plt;0.05).These results suggest that the lesion of microcirculation play an important role in the later AHNP,and Tanshin has some effects on the AHNP by modifying the microcirculation of the pancreas.
In order to investigate the survival mechanism and the role of venous drainage in arterialized venous skin flap, 60 rabbits’ ears were used for research and clinical application of the flap was performed subsequently in two cases. The rabbits were divided into 4 groups. Experimental group was standard arterialized venous skin flap, control 1 group was venous skin flap, control 2 group was arterialized venous skin flap with only one drainage vein and control 3 group was normal skin flap. The process of survival of the flaps was observed by hemodynamic and histological method. The results showed that there was no significant difference between standard arterialized venous skin flap and normal skin flap (P gt; 0.01). Two cases of arterialized venous skin flap survived completely. The conclusion were as follow: 1. the opening of collateral circulation between the veinlets was the main change of the microcirculation; 2. the blood flow of the graft was changed from unphysiological circulation to physiological circulation as the time elapsed and 3. amelioration of venous drainage was important in inproving the survival rate of arterialized vein graft.
OBJECTIVE: To study the forms of microcirculation of arterialized venous flap. METHODS: Twenty New Zealand rabbits were equally divided into two groups, arterialized venous flap group (group A) and control group (group B). The microcirculatory haemodynamic of arterialized venous flap was studied through observation of transparent chamber in rabbit’s ears with aspecial TV set with manification of 1000. RESULTS: The blood of arterilized venous flap flowed through venule anastomosis and drained to another venule. CONCLUSION: It is the main form of microcirculation in early stage that blood flows from venule to draining venule by way of communicating networks between venules.
ObjectiveTo observe the changes of choroid, macular microcirculation and retinal light sensitivity (MS) in people with different degrees of myopia and emmetropia, and to analyze the relationship between them and the axial length (AL).MethodsA cross-sectional observational study. From May 2019 to November 2020, 142 people (142 eyes) of different degrees of myopia and volunteers from Nanchang Aier Eye Hospital were included in the study. All subjects underwent comprehensive optometry, OCT angiography (OCTA), micro-perimetry examination, and axial length (AL) measurement. A frequency domain OCTA instrument was used to measure the blood flow density of the superficial retinal capillary plexus (SVD), the blood flow density of the deep capillary plexus (DVD), the area of the foveal avascular zone (FAZ) and the choroidal capillaries in the 6 mm×6 mm area of the macula, and percentage of vascular blood flow blank area (FD). The macular integrity assessment instrument was used to measure macular 10° retinal MS and macular fovea 2°, 4° fixation rate (P1, P2), 63% and 95% hyperbolic ellipse area (BCEA). Pairwise comparisons between groups were tested by the least significant difference method.ResultsAmong 142 eyes, 68 eyes were in male, 74 eyes were in female. According to different equivalent spherical powers (SER), subjects were divided into emmetropia group, low myopia group, moderate myopia group, and high myopia group, with 31 eyes, 36 eyes, 44 eyes, and 31 eyes, respectively. Compared with SER (H=132.776) and AL (F=61.118) of the tested eyes in the 4 groups, the difference was statistically significant. The SVD (P=0.003, 0.002, 0.003) and DVD (P＜0.001,＜0.001, P=0.001) of the emmetropia group, low myopia group, and moderate myopia group were higher than those of the high myopia group, and the difference was statistically significant. The FAZ area of the emmetropia group was higher than that of the moderate myopia group, the difference was statistically significant (P=0.013). The FD percentage of choroidal capillaries in the moderate myopia group and the high myopia group was higher than that of the emmetropia group, the difference was statistically significant (P=0.011, 0.030). MS in the high myopia group was significantly lower than that in the emmetropia group, low myopia group, and moderate myopia group, the difference was statistically significant (P＜0.001,＜0.001, P=0.035). Compared with 63% BCEA, 95% BCEA, P1 and P2 among subjects in the emmetropia group, low myopia group, moderate myopia group, and high myopia group, the difference was not statistically significant (H=6.936, 7.041, 5.450, 4.239; P>0.05). The results of correlation analysis showed that the macular area SVD (r=－0.256, P=0.002), DVD (r=－0.465, P＜0.001), FAZ area (r=－0.308, P＜0.001) were negatively correlated with AL. The percentage of FD of choroidal capillaries was positively correlated with AL (r=0.170, P=0.043). Retinal MS was positively correlated with SVD (r=0.252, P=0.003), DVD (r=0.298, P＜0.001), FAZ area (r=0.334, P＜0.001), it was negatively correlated with AL (r=－0.439, P＜0.001), it was not related to the percentage of FD of choroidal capillaries (r=－0.061, P=0.473).ConclusionsWith the increase of myopic refractive power and AL, the macular area SVD, DVD, and retinal MS all show a downward trend. The decline of retinal MS is related to the decrease of SVD and DVD.
In order to observe the effect of far infrared rays on the survival of skin flap, the following experiment was performed. Forty-eight SD rats were selected and divided into two groups. The rats received 0.3 w/cm2 radiation twice a day from 3 days before operation to 5 days after operation in the experimental group, while in the control group the rats received none before or after the operation. The flap was designed as 2 cm x 6 cm in the back of the rats with the pedicle caudalward. The microcirculatory changes of the flap were observed, and the survival area of the flap was calculated. The results showed that either in the proximal or in the distal part of the graft, in the experimental group, the mean opening rate, diameter and the flowing velocity of the microvessels were significantly higher than those in the control group (P lt; 0. 05). The mean rate of survival area of the experimental group (80.5%) was also higher than that of the control group (62.7%) (P lt; 0.01). It was suggested that radiation with far infrared rays could dilate the microvessels, improve the flap microcirculation, therefore, enhance the survival of the randomized skin flap.
ObjectiveTo observe the retinal microcirculation changes in chinchilla rabbit with branch retinal vein occlusion (BRVO), and to evaluate the feasibility of laser speckle imaging (LSI) technology as monitoring tool for retinal microcirculation. MethodsTen 4-month-old chinchilla rabbits were used for the experiment, selecting the right eye as the experimental eye. The main retinal vein, adjacent 0.5-1.0 mm to the optic of rabbit retina, was selected to the target vessel under surgical microscope. The software of LSI instrument was used to measure the diameter of target vein and blood flow of 0.2 mm2 area of target vein. The BRVO rabbit model was induced by photodynamic therapy, then measure the diameter and blood flow in the same region using the method as before and after 10 minutes modeled. ResultsThe retinal color pictures, infrared laser and the distribution of blood flow pseudo-color were synchronous displayed by LSI technology. Before and after modeling, the target vessel diameter were (0.104±0.009), (0.128±0.008) mm, and the 0.2 mm2 area blood flow of target vessel were (563.500±28.788), (256.000±53.319) PU. The diameter of target blood vessel after modeling was significantly thicker than before, with the significant difference (t=12.14,P=0.008). The blood flow in 0.2 mm2 area of target vessel was significantly lower than before, also with the significant difference (t=183.00,P=0.009). ConclusionsThe diameter of target vessel of the BRVO rabbit model is enlarged, and the target vessel area of 0.2 mm2 blood flow is reduced significantly. LSI system can monitor the retinal microcirculation real-time and quantitatively.