Improvement Of Nepeta Angustifolia Extract On Renal Mesangial Cellapoptosis And HGHFD/STZ-induced Diabetic Nephropathy

As an important medicinal material constituting a variety of traditional Chinese medicine prescriptions,Nepeta angustifolia C.Y.Wu was used as a folk medicine to treat various vascular-related diseases including apoplexia,and cerebral haemorrhage in Tibet,China.Studies have shown that this plant has an excellent protective effect on cerebral hemorrhage and vascular dysfunction in diabetic rats.The purpose of this study was to identify novel pharmacological activities of N.angustifolia,including inhibition of glomerular mesangial cell apoptosis and improvement of diabetic nephropathy（DN）.The H₂O₂-induced HBZY-1 cells model were used to evaluate the cell protective effect of ethanol extracts of N.angustifolia（NA,50μg/mL,100μg/mL,200μg/mL）.The indicators oxidative stress,apoptosis,mitochondrial membrane potential,and the protein expression levels of caspase 3 and caspase 9 were measured.In animal experiments,the high-glucose and high-fat diet combined with low-dose streptozotocin（HGHFD/STZ）-induced diabetic nephropathy rat model was used to study the effects of NA on DN.After 8 weeks of administration,sreum,urine and kidney tissues were collected for subsequent experiments.The levels of creatinine（Cr）and urea nitrogen（BUN）in serum and urine were measured,as well as urine protein content.The levels of oxidative stress markers and proinflammatory mediators in nephridial tissue were also detected.For renal histopathology,H&E staining,PAS staining and Masson staining were used for observation.In vitro,NA（50μg/mL,100μg/mL,200μg/mL）could significantly inhibit H₂O₂-stimulated HBZY-1 cells injury.Pretreatment of cells with NA significantly reverse these changes of ROS,SOD and MDA in HBZY-1 cells exposed to H₂O₂.Moreover,pretreatment with Schizonepeta tenuifolia could prevent apoptosis,improve mitochondria damage and inhibit caspases3/9 activation.In vivo,the blood glucose,urine volume,kidney index and proteinuria of rats in NA groups were significantly improved.Compared with the DM group,the serum and urine Cr and BUN levels in NA groups were returned to normal.After 8 weeks of treatment with NA（60 mg/kg,120 mg/kg,240 mg/kg）,the release of oxidative stress and pro-inflammatory mediators were significantly down-regulated in renal.Observation of renal histopathological sections shown that NA can significantly improve glomerular hypertrophy,glycogen deposition and renal fibrosis caused by diabetic nephropathy.In conclusion,in vitro studies have shown that NA can inhibit oxidative stress induced mesangial cells apoptosis by improving mitochondrial potential and reducing caspases-madiated signaling pathway.In vivo,NA has obvious protection effect on renal dysfunction in DN rats.Our research provides the therapeutic potential of N.angustifolia on DN.