Genome-edited rabbits:Unleashing the potential of a promising experimental animal model across diverse diseases

Animal models are extensively used in all aspects of biomedical research,with substantial contributions to our understanding of diseases,the development of pharmaceuticals,and the exploration of gene functions.The field of genome modification in rabbits has progressed slowly.However,recent advancements,particularly in CRISPR/Cas9-related technologies,have catalyzed the successful development of various genome-edited rabbit models to mimic diverse diseases,including cardiovascular disorders,immunodeficiencies,agingrelated ailments,neurological diseases,and ophthalmic pathologies.These models hold great promise in advancing biomedical research due to their closer physiological and biochemical resemblance to humans compared to mice.This review aims to summarize the novel gene-editing approaches currently available for rabbits and present the applications and prospects of such models in biomedicine,underscoring their impact and future potential in translational medicine.

Calcium-chelating peptides from rabbit bone collagen:characterization,identification and mechanism elucidation

This study aimed to characterize and identify calcium-chelating peptides from rabbit bone collagen and explore the underlying chelating mechanism.Collagen peptides and calcium were extracted from rabbit bone by instant ejection steam explosion(ICSE)combined with enzymatic hydrolysis,followed by chelation reaction to prepare rabbit bone peptide-calcium chelate(RBCP-Ca).The chelating sites were further analyzed by liquid chromatography-tandem mass(LC-MS/MS)spectrometry while the chelating mechanism and binding modes were investigated.The structural characterization revealed that RBCP successfully chelated with calcium ions.Furthermore,LC-MS/MS analysis indicated that the binding sites included both acidic amino acids(Asp and Glu)and basic amino acids(Lys and Arg),Interestingly,three binding modes,namely Inter-Linking,Loop-Linking and Mono-Linking were for the first time found,while Inter-Linking mode accounted for the highest proportion(75.1%),suggesting that chelation of calcium ions frequently occurred between two peptides.Overall,this study provides a theoretical basis for the elucidation of chelation mechanism of calcium-chelating peptides.

Betaine addition to the diet alleviates intestinal injury in growing rabbits during the summer heat through the AAT/mTOR pathway

Background The aim of this experiment was to investigate the effect of different levels of betaine(Bet)inclusion in the diet on the intestinal health of growing rabbits under summer heat.A total of 100 weaned Qixing meat rabbits aged 35 d with body weight of 748.61±38.59 g were randomly divided into 5 treatment groups:control group(basal diet)and Bet groups(basal diet+0.75,1.0,1.5 or 2.0 g/kg Bet).The average daily temperature in the rabbitry during the experiment was 30.48°C and the relative humidity was 69.44%.Results Dietary addition of Bet had no significant effect on growth performance and health status of growing rabbits(P>0.05),but it increased ileal secretory immunoglobulin A content compared to the control under summer heat(P<0.05).Addition of 0.75 g/kg Bet up-regulated jejunal IL-4,down-regulated ileal TNF-αexpression(P<0.05).The addition of 1.0 g/kg Bet increased the villi height(VH)in the jejunum(P<0.05).Serum glucose levels were reduced,and the expression of SLC6A20 was up-regulated in jejunum and ileum of rabbits fed with 1.5 g/kg Bet(P<0.05).When added at 2.0 g/kg,Bet reduced serum HSP70 content,increased jejunal VH,and up-regulated duodenal SLC7A6,SLC38A2,mTOR and 4EBP-2 expression(P<0.05).Correlation analysis revealed that intestinal mTOR expression was significantly and positively correlated with SLC7A6,SLC38A2,SLC36A1 and IL-4 expression(P<0.05).Conclusions Dietary addition of Bet can up-regulate the expression of anti-inflammatory factors through the AAT/mTOR pathway,improve the intestinal immune function,alleviate intestinal damage in growing rabbits caused by summer heat,and improve intestinal health.

Methods to Reduce the Hypoglycemic Mortality of Alloxan in Diabetic Rabbit Model

Objective: To explore an intervention method to reduce the mortality of alloxan diabetes model, and to preliminarily analyze the mechanism of alloxan induced animal death. Methods: Healthy New Zealand rabbits were randomly divided into injection group, control group, experimental group and blank group. The single injection group was injected with 100 mg/kg alloxan once. The control group was given 5% glucose solution and 100 mg/kg alloxan was injected in two times. The experimental group was given 5% glucose solution orally, 100 mg/kg alloxan, 7 mL 0.9% NaCl intravenously and 5 mL 5% glucose intraperitoneally immediately, and blood glucose was continuously monitored, 10 mL 5% glucose intravenously and 10 mL 5% glucose intraperitoneally every 4 h in the hypoglycemic stage. The blank group does nothing. Liver and kidney tissues at different time periods were stained with HE and organ index was evaluated. Results: 1) A single injection of 100 mg/kg alloxan without any intervention resulted in 100% mortality. Before modeling, oral administration of 5% glucose solution, divided into two injections of 100 mg/kg alloxan, mortality reached 100%;A single injection of 100 mg/kg alloxan and continuous intervention of normal saline and glucose for 20 h can significantly reduce the mortality of alloxan induced diabetic rabbit model. 2) Liver and kidney tissues were damaged in different degrees at different time periods, and liver and kidney indexes were significantly increased after alloxan injection compared with the normal group, with statistical significance (P > 0.05). Conclusion: 1) Every 4 hours of hypoglycemia, 10 ml 5% glucose was injected intravenously 10 ml 5% glucose intraperitoneally. It can reduce the death rate of alloxan diabetic rabbit model and shorten the time of blood glucose measurement. 2) After the injection of alloxan, acute lesions of liver and kidney may occur in different degrees, or one of the causes of acute death of experimental animals.

Intravitreal slow-release dexamethasone alleviates traumatic proliferative vitreoretinopathy by inhibiting persistent inflammation and Müller cell gliosis in rabbits

AIM:To evaluate the effects of intravitreal slow-release dexamethasone on traumatic proliferative vitreoretinopathy(PVR)and Müller cell gliosis and preliminarily explored the possible inflammatory mechanism in a rabbit model induced by penetrating ocular trauma.METHODS:Traumatic PVR was induced in the right eyes of pigmented rabbits by performing an 8-mm circumferential scleral incision placed 2.5 mm behind the limbus,followed by treatment with a slow-release dexamethasone implant(Ozurdex)or sham injection.Left eyes were used as normal controls.The intraocular pressure(IOP)was monitored using an iCare tonometer.PVR severity was evaluated via anatomical and histopathological examinations every week for 6wk;specific inflammatory cytokine and proliferative marker levels were measured by quantitative real-time polymerase chain reaction,Western blot,protein chip analysis,or immunofluorescence staining.RESULTS:During the observation period,PVR severity gradually increased.Intense Müller cell gliosis was observed in the peripheral retina near the wound and in the whole retina of PVR group.Ozurdex significantly alleviated PVR development and Müller cell gliosis.Post-traumatic inflammation fluctuated and was persistent.The interleukin-1β(IL-1β)mRNA level was significantly upregulated,peaking on day 3 and increasing again on day 21 after injury.The expression of nod-like receptor family pyrin domain containing 3(NLRP3)showed a similar trend that began earlier than that of IL-1βexpression.Ozurdex suppressed the expression of IL-1β,NLRP3,and phosphorylated nuclear factor-kappa B(NF-κB).The average IOP after treatment was within normal limits.CONCLUSION:The present study demonstrates chronic and fluctuating inflammation in a traumatic PVR rabbit model over 6wk.Ozurdex treatment significantly inhibites inflammatory cytokines expression and Müller cell gliosis,and thus alleviates PVR severity.This study highlights the important role of IL-1β,and Ozurdex inhibites inflammation presumably via the NF-κB/NLRP3/IL-1βinflammatory axis.In summary,Ozurdex provides a potential therapeutic option for traumatic PVR.

Rabbit models of dry eye disease: comparative analysis

AIM:To report ocular changes in rabbits after the implementation of three different induction methods to create dry eye(DE)conditions and provides evidence of DErelated disease evolution.METHODS:Experimental methods were divided into 3 models.The first model used involved triple injection of complete Freund’s adjuvant,50µL each,also called the meibomian gland dysfunction(MGD)model.In the second model,DE conditions were created by the resection of nictitating membranes(NM),Harderian glands(HG),and main lacrimal glands(LG),also called the LGR model.The third model involved the topical administration of benzalkonium chloride(BAK)0.1%solution.The Schirmer test,ocular surface staining with fluorescein,and tear breakup time tests were implemented before and after excision.After euthanasia,the ocular tissues were dissected.Cornea,conjunctiva,and meibomian glands were treated with periodic acid–Schiff(PAS)staining and haematoxylin–eosin staining.RESULTS:The MGD model triggered inflammation of meibomian glands.It detected changes in the lipid layer of the tear film.The bilateral resection of NM,HG,and LG reduced the watering layer of the tear film.The topical administration of BAK of 0.1%solution impacted the mucosal layer of the tear film.CONCLUSION:Different changes are observed with different DE syndrome models.The composition of the tear film differ depending on which part of the eye is targeted.More studies need to be done to confirm whether an increased thickness of the cornea has any impact on the DE disease.

Effect of taxifolin on cold-shock damages in spermatozoa in rabbits

Objective:To investigate the effect of taxifolin added to rabbit semen on freezing-induced cold-shock damages in spermatozoa.Methods:Semen was collected from six adult New Zealand rabbits once a week by artificial vagina.The collected semen was pooled at 38℃ and divided into four equal volumes.They were diluted with 0,50,100 and 200μM taxifolin-containing Tris+egg yolk extender at 38℃ and their temperatures were lowered to 4℃.Following equilibration,semen drawn into 0.25 mL straws were frozen in an automatic semen freezing device and stored in liquid nitrogen container at-196℃.Samples were thawed in 38℃ water for 25 s and the analyses of motility,kinematic parameters,morphological deformities,changes in membrane integrity,mitochondrial membrane potential,dead-live ratio,acrosomal damages and as well as oxidative stress analyses were performed in semen.Results:Addition of 50μM taxifolin significantly improved motility(total,progressive,rapid and static),high mitochondrial membrane potential and the ratios of spermatozoa with acrosomal damage compared to the control group.Compared to the control group,malondialdehyde(MDA)levels in the 50 and 100μM taxifolin groups were significantly lower,while the MDA level was high and viable spermatozoa ratio was low in the 200μM taxifolin group.There were no significant differences between the groups in terms of kinematic parameters,morphological deformities,membrane integrity and antioxidant levels.Conclusions:The low dose of taxifolin(50μM)has a positive effect and the high dose(200μM)has a negative effect.Therefore,it is concluded that the addition of low-dose(50μM)taxifolin to the extenders would be a useful additive in reducing cold-shock damage that occurs during freezing of rabbit semen.

A novel approach for 25-gauge transconjunctival sutureless vitrectomy to evaluate vitreous substitutes in rabbits

AIM:To improve the standard three-port vitrectomy for establishing and evaluating an endotamponade model in rabbits.METHODS:Three ports were prepared near the third eyelid of rabbits,and the infusion port was placed at the inferior nasal quadrant with the inserted cannula linking with a self-designed handheld rigid infusion catheter.All right eyes of rabbits underwent a modified 25-gauge vitrectomy and were subsequently filled with balanced salt solution,silicone oil,and eight-arm polyethylene glycols(8-arm PEGs)hydrogel separately for comparison.Ophthalmic examinations were performed regularly to record the changes after the surgery.RESULTS:Successful vitrectomy was achieved among 44 chinchilla rabbits.The mean operation time was 4.51±1.25min.Four eyes(9.1%)presented limited lens touch and two eyes(4.5%)showed retinal touch during surgery.Incision leakage was found in three eyes(6.8%)after surgery.There was no endophthalmitis,hemorrhage,or retinal detachment during the observation period and ophthalmic examinations after the implantation of vitreous substitutes.CONCLUSION:The modified technique of the standard vitrectomy applied in the endotamponade model in rabbits shows excellent safety and practicality.

Comment on:Optic neuropathy and increased retinal glial fibrillary acidic protein due to microbead-induced ocular hypertension in the rabbit

Dear Editor,W e read with great interest the study by Zhao et al[1],which evaluated optic neuropathy and changes in the amount of glial fibrillary acidic protein in the retina with intracameral injection of microbeads into rabbits.The objective was to investigate whether the injection of microbeads into the anterior chamber can induce chronic intraocular hypertension in a glaucoma model in rabbits.

Effect of a novel tyrosine kinase inhibitor nintedanib on bFGF and VEGF concentrations in a rabbit retinal vein occlusion model

AIM:To evaluate whether a novel tyrosine kinase inhibitor nintedanib could inhibit basic fibroblast growth factor(bFGF)and vascular endothelial growth factor(VEGF)simultaneously for retinal vascular disease in vivo.METHODS:After a laser induced rabbit retinal vein occlusion(RVO)model was made,0.5 mg of nintedanib was injected intravitreally in the left eye on the third day while the right eye was as a control.Intracameral samples were taken on the day before laser treatment and days 1,3,7,14,21,and 28 after treatment.Enzyme-linked immunosorbent assay(ELISA)was used to test the bFGF and VEGF-A concentrations in the aqueous humor.RESULTS:Both bFGF and VEGF-A rose significantly on the third day after laser treatment in both eyes.In the control eye the bFGF concentration peaked on the 14th day while the VEGF-A concentration dropped rapidly soon after the third day.After nintadanib injection in the study eye,both bFGF and VEGF-A showed a significant reduction on the 4th day(7th day after laser treatment)when compared to the control eye,and kept on low level in the following several weeks.CONCLUSION:Intravitreal injection of nintedanib can inhibit the expression of bFGF and VEGF in the process of RVO model to a certain extent,which is expected to become a new method for the treatment of retinal vascular diseases or fibrotic diseases.

Hypotensive Effects of an Aqueous Extract of Bambusa vulgaris (Poaceae) Leaves in Rabbit Oryctolagus cuniculus

Plant of Bambusa vulgaris is used in traditional medicine practice for the management of many pathologies including hypertension. The effect of the aqueous extract of the leaves of Bambusa vulgaris on blood pressure was evaluated in normotensive male rabbits. Blood pressure was measured by the invasive method. Thus, aqueous extract of Bambusa vulgaris leaves had been injected intravenously at doses ranging from 1 mg/kg to 30 mg/kg in rabbits anesthetized with thiopental. The effects of this extract on blood pressure were also evaluated in rabbits having previously received different doses of atropine. The aqueous extract of Bambusa vulgaris leaves induced a dose-dependent hypotension which is not canceled in the presence of atropine. The results obtained show that the extract has blood pressure lowering effect which may be mediated by muscarinic-type cholinergic receptors.

Rabbit Intensification Systems in Rwanda: Feeding Influence and Growth

A study was conducted in Northern Province of Rwanda, from the College of Agriculture and Veterinary Medicine, Busogo Campus located in Musanze district to evaluate the effect of feed type on rabbit growth in rabbit intensification systems in Rwanda. The Complete Randomized Design (CRD) was used and data were collected on rabbit growth weekly for a period of 12 weeks. The experiment was composed of three treatments replicated ten times. The treatments included three types of feeds namely;cabbage combined with Mucuna pruriens added to local forage (I), cabbages combined with Leucaena leucocephala added to local forage (II) and a control composed of other varieties of locally available forage, such as Bidens pilosa, Crassocephalum vitellium and Galinsoga parviflora (III) which was considered as the control (Farmers practice). The feeds were given to ten rabbits separated in individual cages, and each rabbit was considered a replicate. Water was given ad libitum. One month old rabbits (weaners) were used and data were collected after one week of adaptation for 12 weeks. The results showed that the mean of weight gain after 12 weeks was 783.3 g, 760.7 g and 705.7 g for feed type I, II and III respectively. The difference between means of feed types after 12 weeks was not significant (p > 0.5), which implied that rabbit growth did not depend on the feed type. The mean weight gain after 8 weeks was 707.5 g, 661.4 g and 577.1 g for feed type I, II and III respectively. At 8 weeks, the difference between means of feed types was significant (p Mucuna pruriens combined with cabbage and local forage were growing faster than rabbits from other treatments at 8 weeks. The researchers recommended that farmers should be facilitated with feeding materials by the concerned institutions. Training of rabbit farmers and further researches on locally available feeding materials were also given as recommendations at the end of this study.

Analysis and Identification of miRNA Expression in the Skeletal Muscle of Sichuan White Rabbits

[Objectives]miRNAs play an important role in the proliferation and differentiation of different myoblasts.This study was conducted to elucidate the complex genetic mechanisms that affect the meat production performance of Sichuan white rabbits and reveal the regulatory role of miRNAs in their muscle growth and meat quality formation.[Methods]Three constructed skeletal muscle libraries of Sichuan white rabbits aged six months were sequenced by the solexa technology to identify known miRNAs,predict new miRNAs and construct an expression profile of muscle miRNAs.[Results]A total of 511 known miRNAs and 42 miRNAs were detected in 34089472 pure sequences,and the proportion of miRNAs with a length of 22 nt was the highest.The number of known miRNA sequences accounted for 71.38%of pure sequences,which was much higher than the proportion of other types of RNAs.The proportion of sequences from exons was 0.38%,indicating a low degree of mRNA degradation in the samples.Base U had the highest proportion at the first position,and the bases with the highest proportions at positions 8 and 10 were U and A,respectively.Muscle-specific miRNAs(miR-1,miR-133,and miR-206)ranked in the top 10 in terms of expression level.The number and expression levels of new miRNAs were lower than those of known miRNAs.The length distribution,base bias at different positions and expression profile characteristics of miRNAs might be related to the biological function of miRNAs in regulating muscle proliferation and differentiation and the action mechanisms with target genes.[Conclusions]The identification and expression of miRNAs in muscle tissues of Sichuan white rabbits will help to understand the complex molecular mechanisms of meat production performance and provide a theoretical basis for the functional research of miRNAs in meat rabbits.

Experimental Study on the Repair Effect of Xianlinggubao Capsule on Osteoporotic Vertebral Compression Fracture in Rabbits

[Objectives]To observe the effect of Xianlinggubao Capsule on osteoporotic vertebral compression fracture(OVCF)in rabbits and the influence mechanism of the repair of fractures.[Methods]Female June age 30 rabbits were randomly divided into control group,model control group and Xianlinggubao group.After bilateral ovariectomy,the model control group and Xianlinggubao group were injected with dexamethasone continuously for 4 weeks,and then the OVCF compound model was established by surgery.The Xianlinggubao group was treated with Xianlinggubao at a dose of 300 mg/(kg·d)for 60 d,while the blank control group and the model control group were treated with the same amount of normal saline for 60 d.The number of blood vessels and the expression of bone morphogenetic protein-2(BMP-2)were detected by immunohistochemical staining and the bone mineral density(BMD)in the callus of the third lumbar fracture area of rabbits was measured.The content of serum phosphorus(P),alkaline phosphatase(ALP)and total calcium(TCa)in rabbit venous blood were measured by automatic biochemical analyzer.The content of vascular endothelial growth factor(VEGF)and platelet-derived growth factor(PDGF)in rabbit venous blood were measured by ELISA kit.[Results]The number of blood vessels and the expression of BMP-2 in the callus of the third lumbar fracture area of rabbits was high in Xianlinggubao group,the content of serum P,ALP,TCa,VEGF and PDGF was obviously increased,BMD was obviously increased,the bone microstructure of the third lumbar vertebrae fracture area of rabbits was basically restored.Compared with the model control group(P<0.05),the difference was statistically significant.[Conclusions]Xianlinggubao Capsule can increase calcium and phosphorus deposition,promote the formation of blood vessels in the fracture area of OVCF in rabbits,and have a strong repair effect on OVCF in rabbits.

Welcoming The Year of The Rabbit

2023 is the Year of the Rabbit in Chinese zodiac.Here are some legends and traits associated with the animal These easy,interesting and catchy Chinese nursery rhymes White Little Rabbit are widely recited by Chinese children:White little rabbits,white upon white,Two little ears,standing upright,Loves eating carrots and some fruit,Bounce-bounce jump-jump oh so cute!The Chinese New Year in 2023 will ring in the Year of the Rabbit,starting from 22 January and ending on 9 February 2024.

Farewell to vicissitudes,wish for a year as active as a rabbit in 2023

Dear readers:Three years, and three more. Over the past three years, while we have been busy embracing all the new laws and regulations, we have also conducted in-depth research into different ingredients and formulas in response to the needs of the time, and discussing with our peers the application and feasibility of frontier technologies at home and abroad. This should have been the norm。

微处理器Rabbit2000与液晶显示控制器KS0108B的接口及编程

介绍以Rabbit2000型微处理器为核心的RabbitCoreRCM2200型模块和三星公司的KS0108B型液晶控制器,并以TRULY公司的M12864-7A7型液晶显示模块为例,用Rabbit2000型微处理器作为主控芯片,采用DynamicC编写液晶显示程序。

Dramatic Changes of Chinese Angola Rabbit Industry from 2011 to 2015:Reasons,Challenges and Recommendations

In recent years,the demand for rabbit fur in international markets has been declining,especially after the "fur hand-ripping" event at the end of 2013 in China.The rabbit fur export of China almost stagnated,and prices dropped significantly.The slowdown of world economic growth caused loss of most fur-skin enterprises.This paper studies changes of Chinese Angola rabbit industry from 2011 to 2015 by focusing on price and trade analysis.The results show that there are two turning points of Chinese Angola rabbit industry,one is the end of 2013,and the other is the mid of 2015.Chinese Angola rabbit and rabbit fur face big challenges,finally some related recommendations are provided.

Effect of Chinese Herbal Feed Additive on Meat Quality of Rex Rabbit

[ Objective] The aim of this study was to provide a theoretical basis for population and application of Chinese herbal feed additive in the rex rabbit breeding. [ Methyl] 108 weaned -rex rabbits aged 40 days were divided into three groups with thirty -six each group. Group A were fed basal diet, while group B were fed basal diet supplemented with 0.3% Chinese herbal feed additive and group C were fed basal diet supplemented with 0.4% Chinese herbal feed additive. The meat quality indexes were measured when feeding to 150 age in days. [ Result] There was significant difference among pH value, water loss rate, storing loss rate and crude protein content in each group （P〈0.05）, but no significant difference was found in tenderness, cooking percentage, moisture content and crude fat content （ P 〉 0.05）. The total content of ami- no acids, essential amino acids and semi essential amino acids as well as main delicious amino acids was highest in group C accounting for 23.84%, 11.47% and 8.32% respectively, next came group B accounting for 20.94%, 10.64% and 6.81% respectively, and lowest in group C （ control group） accounting for 19.06%, 9.61% and 6.46% respectively. [ Conclusion] The Chinese herbal feed additive can improve meat quality of rex rabbit the best addition of 0.4%.

基于Rabbit2000的嵌入式测控系统

在简要回顾Internet及测控技术发展历史的基础上 ,阐明了当前测控技术向着嵌入式系统方向发展这一趋势 ,着重给出了Rabbit 2 0 0