Current and future policies regarding laboratory animal welfare

Down-regulation of Risa improves podocyte injury by enhancing autophagy in diabetic nephropathy

BACKGROUND

LncRNA AK044604 (regulator of insulin sensitivity and autophagy, Risa) and autophagy-related factors Sirt1 and GSK3β play important roles in diabetic nephropathy (DN). In this study, we sought to explore the effect of Risa on Sirt1/GSK3β-induced podocyte injury.

METHODS

Diabetic db/db mice received Risa-inhibition adeno-associated virus (AAV) via tail vein injection, and intraperitoneal injection of lithium chloride (LiCl). Blood, urine, and kidney tissue samples were collected and analyzed at different time points. Immortalized mouse podocyte cells (MPCs) were cultured and treated with Risa-inhibition lentivirus (LV), EX-527, and LiCl. MPCs were collected under different stimulations as noted. The effects of Risa on podocyte autophagy were examined by qRT-PCR, Western blotting analysis, transmission electron microscopy, Periodic Acid-Schiff staining, and immunofluorescence staining.

RESULTS

Risa and activated GSK3β were overexpressed, but Sirt1 was downregulated in DN mice and high glucose-treated MPCs (P < 0.001, db/m vs. db/db, NG or HM vs. HG), which was correlated with poor prognosis. Risa overexpression attenuated Sirt1-mediated downstream autophagy levels and aggravated podocyte injury by inhibiting the expression of Sirt1 (P < 0.001, db/m vs. db/db, NG or HM vs. HG). In contrast, Risa suppression enhanced Sirt1-induced autophagy and attenuated podocyte injury, which could be abrogated by EX-527 (P < 0.001, db/db + Risa-AAV vs. db/db, HG + Risa-LV vs. HG). Furthermore, LiCl treatment could restore GSK3β-mediated autophagy of podocytes (P < 0.001, db/db + LiCl vs. db/db, HG + LiCl vs. HG), suggesting that Risa overexpression aggravated podocyte injury by decreasing autophagy.

CONCLUSION

Risa could inhibit autophagy by regulating the Sirt1/GSK3β axis, thereby aggravating podocyte injury in DN. Risa may serve as a therapeutic target for the treatment of DN.

Feasibility of large experimental animal models in testing novel therapeutic strategies for diabetes

Diabetes is among the top 10 causes of death in adults and caused approximately four million deaths worldwide in 2017. The incidence and prevalence of diabetes is predicted to increase. To alleviate this potentially severe situation, safer and more effective therapeutics are urgently required. Mice have long been the mainstay as preclinical models for basic research on diabetes, although they are not ideally suited for translating basic knowledge into clinical applications. To validate and optimize novel therapeutics for safe application in humans, an appropriate large animal model is needed. Large animals, especially pigs, are well suited for biomedical research and share many similarities with humans, including body size, anatomical features, physiology, and pathophysiology. Moreover, pigs already play an important role in translational studies, including clinical trials for xenotransplantation. Progress in genetic engineering over the past few decades has facilitated the development of transgenic animals, including porcine models of diabetes. This article discusses features that attest to the attractiveness of genetically modified porcine models of diabetes for testing novel treatment strategies using recent technical advances.

Oxidative stress and pulmonary changes in experimental liver cirrhosis

The use of carbon tetrachloride (CCl₄) in rats is an experimental model of hepatic tissue damage; which leads to fibrosis, and at the long term, cirrhosis. Cirrhosis is the consequence of progressive continued liver damage, it may be reversible when the damaging noxae have been withdrawn. The aim of this study is to evaluate the changes caused by cirrhosis in lung and liver, through the experimental model of intraperitoneal CCI₄ administration. We used 18 male Wistar rats divided into three groups: control (CO) and two groups divided by the time of cirrhosis induction by CCI₄: G1 (11 weeks), G2 (16 weeks). We found significant increase of transaminase levels and lipid peroxidation (TBARS) in liver and lung tissue and also increased antioxidant enzymes SOD and CAT, as well as the expression of TNF-α and IL-1β in the lung of cirrhotic animals. We observed changes in gas exchange in both cirrhotic groups. We can conclude that our model reproduces a model of liver cirrhosis, which causes alterations in the pulmonary system that leads to changes in gas exchange and size of pulmonary vessels.