Evaluation Value Of Ultrasound Multimodality On Renal Microcirculation Perfusion Damage Of Dendrobium Candidum Anti-hepatic Fibrosis Model Rats

Objective:To explore the application value of conventional ultrasound,color Doppler ultrasound（CDFI）,ultra micro blood flow（SMI）,and contrast-enhanced ultrasound（CEUS）multimodal techniques in evaluating the improvement of renal microcirculation perfusion damage by Dendrobium candidum in rats with hepatic fibrosis（HF）.Materials and methods:Fifty-six male SD rats were selected and randomly divided into a negative control group of twenty and a model group of thirty-six.The model group rats were induced to develop a liver fibrosis（HF）animal model by subcutaneous injection of CCl₄.The negative control group was given an equal amount of physiological saline twice a week for five consecutive weeks.Four rats in the negative control group and model group were randomly killed,and liver tissue was taken and sliced.HE staining and Masson staining were used to observe the pathological morphology of liver tissue,Determine whether HF modeling is successful.After successful modeling,the modeling group continued to subcutaneously inject three weeks of CCl₄to induce HF induced renal injury animal models.Then,sixteen mice were randomly selected as the negative control group（NG）,and sixteen mice were randomly selected as the model group（MG）and the Dendrobium officinale intervention group（DG）.DG was administered daily with high-dose fresh extract of Dendrobium officinale（7.5 g/kg）for four weeks,while NG and MG were administered with equal amounts of physiological saline.The morphology of rat kidney was observed by conventional ultrasound and its long diameter,anteroposterior diameter,and thickness of renal cortex were measured.CDFI and SMI were used to observe the grading of rat kidney blood vessels.CEUS was used to detect the parameters of renal cortex blood perfusion,namely,time to peak（TTP）,peak intensity（PSI）,slope of curve rise（A）,and area under curve（AUC）;The twenty-four hour urine and abdominal aorta blood of rats were collected 0ne day before death,and the urine,blood creatinine（Cr）and blood urea nitrogen（BUN）were measured with automatic biochemical detector,and the endogenous creatinine clearance rate（Ccr）was calculated,Compare the differences of the above parameters in each group.The liver and kidney tissues were taken for HE and Masson staining to observe the pathological changes and liver and kidney index changes.Results:（1）General situation and average body mass change of rats.The diet,spirit and activity of NG rats were normal,and their body mass increased rapidly;The food intake and autonomous behavior of MG rats decreased,the spirit became significantly worse,the hair became yellow and fell off,the body mass increased slowly,and the weight loss was obvious in the later stage;Compared with MG,the symptoms of DG were alleviated and the body mass was increased.（2）Histopathological changes of liver and kidney.（1）The HE and Masson staining results of liver tissue showed that the structure of NG liver lobule was normal,the hepatic cord was closely arranged in a radial shape with the central vein as the center,and there was no inflammatory cell infiltration and fibrosis in the portal area;In MG,the hepatic cords were arranged in disorder,a large number of fat vacuoles were seen in the hepatocytes,the portal area was significantly expanded,and inflammatory cell infiltration,a large number of fibrous septa and pseudolobules were seen;Compared with MG,the HF of DG was improved to different degrees,the infiltration of inflammatory cells in the portal area was reduced,and the distribution of fibrous septa and pseudolobules was reduced.（2）HE staining of renal tissue showed that there were no obvious abnormal pathological changes in glomerulus,renal tubules and interstitial areas of rats in each group.（3）Comparison of blood and urine indicators.Compared with NG,the levels of Cr and BUN in blood of MG and DG rats increased,while the levels of Ccr decreased,with statistical significance（all P<0.01）;Compared with MG,the levels of Cr and BUN in blood of DG rats decreased,while the levels of Ccr increased,with significant differences（all P<0.01）.（4）Comparison of liver index（LI）.Compared with NG,LI in MG rats was significantly higher（P<0.05）,indicating that the hepatotoxicity drug CCl₄caused HF,suggesting that the HF model was established;Compared with MG,the LI of DG decreased（P<0.05）.（5）Comparison of Kidney Index（KI）.Compared with NG,the KI of MG and DG increased（P<0.05）;Compared with MG,the KI of DG rats decreased（P<0.05）.（6）Comparison of conventional ultrasound,CDFI,SMI and CEUS examination results of kidney.（1）Routine ultrasound examination showed that there was no statistically significant difference in the long diameter,anteroposterior diameter and renal cortex thickness of rats in each group.（2）CDFI and SMI examinations showed that the renal blood vessels of NG rats were mainly graded at levels 4 and 5,and the main and peripheral blood vessels of the entire renal blood flow were clearly displayed;The vascular grading of MG and DG is lower than that of NG,with grade 3 blood vessels being the main type.The main renal blood flow becomes thinner,and peripheral blood vessels（arcuate arteries and interlobular arteries）are almost invisible;Compared with MG,the vascular grading of DG has a higher degree of overlap from the naked eye,and some of the grading has some differences and ambiguity.The main trunk is thicker,and a few of interlobar arteries are slightly stronger than MG.The advantage of SMI is reflected in the display of renal cortex peripheral vessels（arcuate arteries and interlobular arteries）.CDFI showed a higher proportion of blood vessels in grades 0-2than SMI（8.70%vs 1.09%）,but SMI showed a higher proportion of blood vessels in grades 4-5 and 3 than CDFI（42.39%vs 39.13%,56.52%vs 52.17%,respectively）,especially for grade 5 vessels,SMI was superior to CDFI（8.70%vs 6.52%）.（3）CEUS examination showed that compared with NG,TTP in renal cortex of MG and DG rats was prolonged,PSI and A were decreased,AUC was increased,and the difference was statistically significant（all P<0.05）;Compared with MG,TTP in renal cortex of DG rats was shortened,PSI and A were increased,AUC was decreased,and the difference was statistically significant（all P<0.05）.Conclusion:（1）After continuous subcutaneous injection of liver toxic drug CCl₄for 8weeks,the renal function indicators Cr and BUN levels increased,Ccr levels decreased,and KI levels increased in MG rats,indicating that sustained HF can cause renal microcirculation perfusion damage;（2）Dendrobium officinale can resist HF,improve the general condition,renal function,and blood flow perfusion of model rats,and have a protective effect on the kidneys;（3）Conventional ultrasound,CDFI and SMI can only reflect the renal microcirculation perfusion at the morphological and vascular levels,while CEUS can effectively reflect the renal hemodynamic changes and the status of microcirculation perfusion in the renal cortex,which is more conducive to early evaluation of renal microcirculation perfusion damage after HF.