Progress in experimental models to investigate the in vivo and in vitro antidiabetic activity of drugs

Diabetes mellitus is one of the world's most prevalent and complex metabolic disorders,and it is a rapidly growing global public health issue.It is characterized by hyperglycemia,a condition involving a high blood glucose level brought on by deficiencies in insulin secretion,decreased activity of insulin,or both.Prolonged effects of diabetes include cardiovascular problems,retinopathy,neuropathy,nephropathy,and vascular alterations in both macro-and micro-blood vessels.In vivo and in vitro models have always been important for investigating and characterizing disease pathogenesis,identifying targets,and reviewing novel treatment options and medications.Fully understanding these models is crucial for the researchers so this review summarizes the different experimental in vivo and in vitro model options used to study diabetes and its consequences.The most popular in vivo studies involves the small animal models,such as rodent models,chemically induced diabetogens like streptozotocin and alloxan,and the possibility of deleting or overexpressing a specific gene by knockout and transgenic technologies on these animals.Other models include virally induced models,diet/nutrition induced diabetic animals,surgically induced models or pancreatectomy models,and non-obese models.Large animals or non-rodent models like porcine(pig),canine(dog),nonhuman primate,and Zebrafish models are also outlined.The in vitro models discussed are murine and human beta-cell lines and pancreatic islets,human stem cells,and organoid cultures.The other enzymatic in vitro tests to assess diabetes include assay of amylase inhibition and inhibition ofα-glucosidase activity.

Pre-clinical evaluation of soybean-based wound dressings and dermal substitute formulations in pig healing and non-healing in vivo models

In the last decade,a new class of natural biomaterials derived from de-fatted soybean fl our processed by either thermoset or extraction procedures has been developed.These biomaterials uniquely combine adaptability to various clinical applications to proven tissue regeneration properties.In the present work,the biomaterials were formulated either as hydrogel or as paste formulation and their potential as wound dressing material or as dermal substitute was assessed by two in vivo models in pig skin:The healing full-thickness punch biopsy model and the non-healing full-thickness polytetrafl uoroethylene(PTFE)chamber model.The results clearly show that collagen deposition is induced by the presence of these biomaterials.A unique pattern of early infl ammatory response,eliciting neutrophils and controlling macrophage infi ltration,is followed by tissue cell colonization of the wound bed with a signifi cant deposition of collagen fi bers.The study also highlighted the importance in the use of optimal formulations and appropriate handling upon implantation.In large size,non-healing wounds,wound dermis was best obtained with the paste formulation as hydrogels appeared to be too loose to ensure lasting scaff olding properties.On the contrary,packing of the granules during the application of paste reduced biomaterial degradation rate and prevent the penetration of newly vascularized tissue,thus impeding grafting of split-thickness autologous skin grafts on the dermal substitute base.

Generation of human/rat xenograft animal model for the study of human donor stem cell behaviors in vivo

AIM： TO accurately and realistically elucidate human stem cell behaviors in vivo and the fundamental mechanisms controlling human stem cell fates in vivo, which is urgently required in regenerative medicine and treatments for some human diseases, a surrogate human-rat chimera model was developed. METHODS： Human-rat chimeras were achieved by in utero transplanting low-density mononuclear cells from human umbilical cord blood into the fetal rats at 9-11 d of gestation, and subsequently, a variety of methods, including flow cytometry, PCR as well as immunohistochemical assay, were used to test the human donor contribution in the recipients. RESULTS： Of 29 live-born recipients, 19 had the presence of human CD45^＋ cells in peripheral blood （PB） detected by flow cytometry, while PCR analysis on genomic DNA from 11 different adult tissues showed that 14 selected from flow cytometry-positive 19 animals possessed of donor-derived human cell engraftment in multiple tissues （i.e. liver, spleen, thymus, heart, kidney, blood, lung, muscle, gut and skin） examined at the time of tissue collection, as confirmed by detecting human 132- microglobulin expression using immunohistochemistry. Tn this xenogeneic system, the engrafted donor-derived human cells persisted in multiple tissues for at least 6 mo after birth. Moreover, transplanted human donor cells underwent site-specific differentiation into CK18-positive human cells in chimeric liver and CEHS-positive human cells in chimeric spleen and thymus of recipients. CONCLUSION： Taken together, these findings suggest that we successfully developed human-rat chimeras, in which xenogeneic human cells exist up to 6 mo later. This humanized small animal model, which offers an in vivo environment more closely resembling to the situations in human, provides an invaluable and effective approach for in vivo investigating human stem cell behaviors, and further in vivo examining fundamental mechanisms controlling human stem cell fates in the future. The potential for new advances in our better understanding the living biological systems in human provided by investigators in humanized animals will remain promising.

From neurogenesis to neuronal regeneration: the amphibian olfactory system as a model to visualize neuronal development in vivo

How do individual neurons develop and how are they in- tegrated into neuronal circuitry？ To answer this question is essential to understand how the nervous system develops and how it is maintained during the adult life. A neural stem cell must go through several stages of maturation, including proliferation, migration, differentiation, and integration, to become fully embedded to an existing neuronal circuit. The knowledge on this topic so far has come mainly from cell culture studies. Studying the development of individual neurons within intact neuronal networks in vivo is inherently difficult. Most neurons are generated form neural stem cells during embryonic and early postnatal development.

Safety and biodegradability of a synthetic dural sealant patch(Liqoseal)in a porcine cranial model

Background:Liqoseal consists of a watertight layer of poly(ester)ether urethane and an adhesive layer containing polyethylene glycol-N-hydroxysuccinimide(PEG-NHS).It is designed to prevent cerebrospinal fluid(CSF)leakage after intradural surgery.This study assessed the safety and biodegradability of Liqoseal in a porcine craniotomy model.Methods:In 32 pigs a craniotomy plus durotomy was performed.In 15 pigs Liqoseal was implanted,in 11 control pigs no sealant was implanted and in 6 control pigs a control dural sealant(Duraseal or Tachosil)was implanted.The safety of Liqoseal was evaluated by clinical,MRI and histological assessment.The degradation of Liqoseal was histologically estimated.Results:Liqoseal,2 mm thick before application,did not swell and significantly was at maximum mean thickness of 2.14(±0.37)mm at one month.The foreign body reaction induced by Liqoseal,Duraseal and Tachosil were comparable.Liqoseal showed no adherence to the arachnoid layer and was completely resorbed between 6 and 12 months postoperatively.In one animal with Liqoseal,an epidural fluid collection containing CSF could not be excluded.Conclusion:Liqoseal seems to be safe for intracranial use and is biodegradable.The safety and performance in humans needs to be further assessed in clinical trials.

Various models of atrial fibrillation induced by acetylcholine and its application in the field of traditional Chinese medicine

Atrial fibrillation is of public health importance and profoundly increases morbidity, mortality and health-related expenditures. Morbidities include the increased risks of cardiovascular outcomes such as heart failure and stroke, and the deleterious effects on quality of life, functional status and cognition. Our purpose is to understand the molecular mechanism of atrial fibrillation, a model under pathological conditions should be established. Acetylcholine, a neurotransmitter in the vagus nerve, has been established with numerous atrial fibrillation models. We will discuss the established model of atrial fibrillation which induced by acetylcholine, aiming to seek a model which are more close to the clinical condition. The underlying mechanisms will be discussed in order to observe the mechanism of antiarrhythmic drugs.

SOCS1/JAK2/STAT3 axis regulates early brain injury induced by subarachnoid hemorrhage via inflammatory responses

The SOCS1/JAK2/STAT3 axis is strongly associated with tumor growth and progression,and participates in cytokine secretion in many diseases.However,the effects of the SOCS1/JAK2/STAT3 axis in experimental subarachnoid hemorrhage remain to be studied.A subarachnoid hemorrhage model was established in rats by infusing autologous blood into the optic chiasm pool.Some rats were first treated with JAK2/STAT3 small interfering RNA(Si-JAK2/Si-STAT3)or overexpression plasmids of JAK2/STAT3.In the brains of subarachnoid hemorrhage model rats,the expression levels of both JAK2 and STAT3 were upregulated and the expression of SOCS1 was downregulated,reaching a peak at 48 hours after injury.Simultaneously,the interactions between JAK2 and SOCS1 were reduced.In contrast,the interactions between JAK2 and STAT3 were markedly enhanced.Si-JAK2 and Si-STAT3 treatment alleviated cortical neuronal cell apoptosis and necrosis,destruction of the blood-brain barrier,brain edema,and cognitive functional impairment after subarachnoid hemorrhage.This was accompanied by decreased phosphorylation of JAK2 and STAT3 protein,decreased total levels of JAK2 and STAT3 protein,and increased SOCS1 protein expression.However,overexpression of JAK2 and STAT3 exerted opposite effects,aggravating subarachnoid hemorrhage-induced early brain injury.Si-JAK2 and Si-STAT3 inhibited M1-type microglial conversion and the release of pro-inflammatory factors(inducible nitric oxide synthase,interleukin-1β,and tumor necrosis factor-α)and increased the release of anti-inflammatory factors(arginase-1,interleukin-10,and interleukin-4).Furthermore,primary neurons stimulated with oxyhemoglobin were used to simulate subarachnoid hemorrhage in vitro,and the JAK2 inhibitor AG490 was used as an intervention.The in vitro results also suggested that neuronal protection is mediated by the inhibition of JAK2 and STAT3 expression.Together,our findings indicate that the SOCS1/JAK2/STAT3 axis contributes to early brain injury after subarachnoid hemorrhage both in vitro and in vivo by inducing inflammatory responses.This study was approved by the Animal Ethics Committee of Anhui Medical University and the First Affiliated Hospital of University of Science and Technology of China(approval No.LLSC-20180202)on March 1,2018.

Dental pulp stem cells express tendon markers under mechanical loading and are a potential cell source for tissue engineering of tendon-like tissue

Postnatal mesenchymal stem cells have the capacity to differentiate into multiple cell lineages. This study explored the possibility of dental pulp stem cells （DPSCs） for potential application in tendon tissue engineering. The expression of tendon- related markers such as scleraxis, tenascin-C, tenomodulin, eye absent homologue 2, collagens I and VI was detected in dental pulp tissue. Interestingly, under mechanical stimulation, these tendon-related markers were significantly enhanced when DPSCs were seeded in aligned polyglycolic acid （PGA） fibre scaffolds. Furthermore, mature tendon-like tissue was formed after transplantation of DPSC-PGA constructs under mechanical loading conditions in a mouse model. This study demonstrates that DPSCs could be a ootential stem cell source for tissue enEineerin~ of tendon-like tissue.

Quantitative Mitochondrial Proteomics Study on Protective Mechanism of Grape Seed Proanthocyanidin Extracts Against Ischemia/Reperfusion Heart Injury in Rat

Cardiac ischemia/reperfusion（I/R） injury is a critical condition,often associated with high morbidity and mortality.The cardioprotective effect of grape seed proanthocyanidin extracts（GSPE） against oxidant injury during I/R has been described in previous studies.However,the underlying molecular mechanisms have not been fully elucidated.This study investigated the effect of GSPE on reperfusion arrhythmias especially ventricular tachycardia（VT） and ventricular fibrillation（VF）,the lactic acid accumulation and the ultrastructure of ischemic cardiomyocytes as well as the global changes of mitochondria proteins in in vivo rat heart model against I/R injury.GSPE significantly reduced the incidence of VF and VT,lessened the lactic acid accumulation and attenuated the ultrastructure damage.Twenty differential proteins related to cardiac protection were revealed by isobaric tag for relative and absolute quantitation（iTRAQ） profiling.These proteins were mainly involved in energy metabolism.Besides,monoamine oxidase A（MAOA） was also identified.The differential expression of several proteins was validated by Western blot.Our study offered important information on the mechanism of GSPE treatment in ischemic heart disease.

Experimental study on pharmacodynamics of pudilan xiaoyan oral liquid for preventing and treating respiratory virus infection

Background:Pudilan Xiaoyan Oral Liquid(PDL),a famous traditional Chinese formula for treating acute and chronic inflammation.To evaluate the broad-spectrum antiviral effect of Pudilan Xiaoyan Oral Liquid,and provide a basis for clinical medication.Methods:Its inhibitory effect on different respiratory viruses was observed by cytopathic test.The potential mechanism of the anti-influenza effect was determined by neuraminidase activity.In order to observe the therapeutic effect of PDL on viral pneumonia caused by different respiratory viruses.The viral pneumonia model was established by nasal infection with different respiratory viruses,and then PDL was given Therapeutic and prophylactically to evaluate its pharmacodynamic activity in vivo.Results:The results of in vitro experiments showed that PDL had different inhibitory effects on cytopathic effects caused by different respiratory viruses.And it has obvious inhibitory effect on the neuraminidase activity of influenza A virus,which indicates that it exerts anti-influenza virus effect by inhibiting neuraminidase activity of influenza virus.The results in vivo showed that PDL exhibited an inhibitory effect on pulmonary index(PI)and effectively reduced the degree of lesions in the lungs.The lethal rate of mice was significantly decreased while survival time of mice was dramatically increased by PDL treatment in comparison to infection control,respectively.Conclusions:Our study demonstrates that PDL had a significant protection and treatment effect for respiratory virus infection in vitro and in vivo.

Enhancing near-infrared II photodynamic therapy with nitric oxide for eradicating multidrug-resistant biofilms in deep tissues

Nitric oxide(NO)enhanced photodynamic therapy(PDT)is a promising approach to overcome drug tolerance and resistance to biofilm but is limited by its short excitation wavelengths and low yield of reactive oxygen species(ROS).Herein,we develop a compelling degradable polymer-based near-infrared II(NIR-II,1000-1700 nm)photosensitizer(PNIR-II),which can maintain 50%PDT efficacy even under a 2.6 cm tissue barrier.Remarkably,PNIR-II is synthesized by alternately connecting the electron donor thiophene to the electron acceptors diketopyrrolopyrrole(DPP)and boron dipyrromethene(BODIPY),where the intramolecular charge transfer properties can be tuned to increase the intersystem crossover rate and decrease the internal conversion rate,thereby stabilizing the NIR-II photodynamic rather than photothermal effect.For exerting a combination therapy to eradicate multidrug-resistant biofilms,PNIR-II is further assembled into nanoparticles(NPs)with a synthetic glutathione-triggered NO donor polymer.Under 1064 nm laser radiation,NPs precisely release ROS and NO that triggered by over-expressed GSH in the biofilm microenvironment,thereby forming more bactericidal reactive nitrogen species(RNS)in vitro and in vivo in the mice model that orderly destroy biofilm of multidrug-resistant Staphylococcus aureus cultures from clinical patients.It thus provides a new outlook for destroy the biofilm of deep tissues.