Therapeutic Effect Of Adipose-derived Mesenchymal Stem Cells On Kidney Injury In Dogs

The kidney is one of the most important metabolic organs in mammals and has unique function in maintaining the body’s water,electrolyte and acid-base balance.When it is injured,it causes clinical symptoms characterized by pain,nausea,emesis,hematuria,etc.,and may lead to systemic multiple organ failure further,and even death.At present,the effective treatment of canine kidney injury is mainly supportive therapy.Renal replacement therapy is difficult to be widely used in dogs shortly due to its high cost.Therefore,there is an urgent need for a new therapy for dogs with kidney injury.Adipose-derived mesenchymal stem cells(ADSCs)are adult stem cells derived from adipose tissue with self-renewal and multi-differentiation capabilities,which considered a promising tool for the treatment of several diseases.Although there are sufficient sources of ADSCs,and they could be rapidly proliferated in vitro.However,there are still many problems such as cumbersome separation and purification,generation differences,aging,etc.,which will affect the therapeutic effect of cells.Immortalized cells are considered ideal seed cells for transplantation therapy,which not only proliferate indefinitely in vitro,but also maintain stability and uniformity.In our previous study,canine ADSCs were successfully immortalized,which were injected intravenously in our established acute kidney injury(AKI)models in mice and dogs in this study.At present,immortalized cells are rarely reported on the treatment of diseases.This study set out to clarify the therapeutic potential of immortalized ADSCs,and further attempted to explore whether changing the serum concentration of the medium would also affect the therapeutic effect of ADSCs.In this study,immortalized canine ADSCs were injected into animals with AKI after resuscitation,resuscitation,passage and culture in vitro.24 mice were divided into two branches:a control group and a gentamicin induced group(this group treated with low-serum ADSC or high-serum ADSC.12 dogs were divided into control,model,and cell-injected groups.The mice in the last three groups were established AKI models with gentamicin(GM),while the control group received an equal volume of saline injection.The dogs were grouping and treating as well as mice.Mice received cells on days 1 and 4 after modeled,and dogs received cell transplantation on day 1 after modeled,while all control animals received an equal volume of saline injection.Serum and kidney samples were taken for testing,and the following results were obtained:(1)After continuous intraperitoneal injection of GM,the serum creatinine and urea nitrogen levels in mice were significantly higher than normal levels,matching the international standards of AKI.H&E staining revealed marked renal tubular damage compared with the control group,indicating that the AKI models were successfully established.The results showed there were improvements in renal function and tissue damage in the kidneys of the mice that received cell injection,and the ADSCs cultured with low-serum showed better effect,indicating that immortalized canine ADSCs played a certain therapeutic role in AKI.(2)Peripheral blood of dogs was collected from the forearm brachial veins once every 2days to detect the continuous changes of serological indicators.The results showed that with the injection of GM,the levels of creatinine and urea nitrogen in canine serum increased continuously.The serum creatinine levels of the model dogs were significantly higher than those of the control group on 7th day,indicating that the canine AKI models were successfully established.After GM injection,the model dogs gradually showed some clinical symptoms such as thirst,depression,anorexia and emesis,and the serological indicators still increased even if the injection of GM was stopped.Moreover,a visual examination of kidneys in the control group showed a smooth,soft,and intact surface.In contrast,the surfaces of kidneys in the GM group were rough with many uneven plaques,a dark red color,and a swollen texture.There were improvements of renal structure and function in dogs,indicating the effectiveness of ADSCs in the treatment of canine AKI.Our findings revealed that immortalized canine ADSCs were effective treatments for AKI induced by GM in mice,and found that cells cultured in low-serum has a better repair effect,which were also effective in allogeneic treatment.These models provide new ideas for the clinical treatment of AKI in domestic animals.