Mitochondrial Function Of Liver And Muscle In Diabetic Mice

Objective: Previous studies find pathological change of liver mitochondria in diabetic patient like swell,structure loss,ridge disorder,structural blur.Some scholars think hyperglycemia can lead to lesion to diabetic liver and skeletal muscles,as well as oxidative stress injury of mitochondria.This research aims to study the transport chain between liver and skeletal muscle mitochondria by testing the oxidative phosphorylation of complete mitochondria,especially the functional change of mitochondria at the beginning and end-stage for type 2 diabetes cases.Also aims to study changes of liver and skeletal muscle mitochondria function of type 1 diabetes mice,especially the observation of oxidative phosphorylation of liver mitochondria between mice of few week age(9 weeks)and mice of middle week age(35 weeks).Method: IPGTT and ITT experiments on 8 respectively 9-week-old male db/db mice and same brood wild mice,are conducted to test their sugar tolerance and insulin sensitivity.We need extract liver and skeletal muscle mitochondria of type 2 diabetes mice of few week age(9 weeks)to measure their mitochondria concentration,oxidative phosphorylation,Calcium retention ability in mitochondria,membrane potential,as well as hydrogen peroxide generation of complete mitochondria,citrate synthase to see the oxidative phosphorylation and activity of mitochondria.Meanwhile,same experiments are conducted to type 2 diabetes mice of more week age(42 weeks)as comparison,to see the functional changes in liver and skeletal muscle mitochondria of different aged type 2 mice.First raise mice model with type 1 diabetes,then conduct the IPGTT and ITT experiments before extracting their liver and skeletal muscle mitochondria;then extract the mitochonodria and conduct concentration measurement and oxidative phosphorylation,at the same time Calcium retention ability in mitochondria,membrane potential,as well as hydrogen peroxide generation of complete mitochondria to see the oxidative phosphorylation and activity of mitochondria.Same method goes with mice of middle week age,after modeling successful,we need to keep raising the mice untill 35 weeks then measure the MDA content and T-AOC and T-SOD content of liver in type 1 diabetes mice of middle week age.Result: 1.Type 2 diabetes mice of fewer week age compared with normal ones in IPGTT experiment,have obvious rise of blood glucose level at every time point except the last one.Type 2 diabetic mice of more week age enjoy obvious rise of blood glucose level at every time point compared with the normal.ITT experiment shows oblivious rise of blood glucose level on both type 2 diabetes mice,compared with the control groups.2.Young type 2 diabetes mice of few week age have higher oxidative phosphorylation level of liver mitochondria than the normal,but the oxidative phosphorylation level of skeletal muscle mitochondria is of little statistical difference.Old type 2 diabetes mice of more week age have also higher oxidative phosphorylation level of liver mitochondria than the normal,but not as apparent as young ones,the oxidative phosphorylation level of skeletal muscle mitochondria is also of little statistical difference.3.The comparison of liver and skeletal muscle mitochondria between type 2 diabetic mice(young and old)and the normal control groups shows that in addition to the membrane potential of old type 2 diabetic mice was significantly lower than normal control mice,no obvious change in Calcium retention ability,hydrogen peroxide generation,membrane potential and citrate synthase.4.Successful modeling: Apparent rise of blood glucose for two differently aged groups of type 1 diabetes mice,compared with the normal control groups.5.Compared with the normal control groups,blood glucose rise apparently at each time point after intraperitoneal injection of glucose into the two differently aged groups of type 1 diabetes mice.ITT shows the blood glucose level is obviously higher than the control groups both for type 1 diabetes mie of few week age or middle week age.6.The level of oxidative phosphorylation of liver mitochondria in Type 1 diabetes mice(few week age or middle week age)rises significantly compared with the control groups.While the skeletal muscle mitochondria show no clear change on oxidative phosphorylation for both type 1 diabetes mice of few or middle week age.7.Comparison of liver and skeletal muscle mitochondria between type 1 diabetes mice(of few or middle week age)and the normal control groups indicates no significant change on Calcium retention ability,membrane potential,hydrogen peroxide generation and citrate synthase level.Conclusion: At different stages of diabetes,type 1 and type 2 diabetes mice both have increase of liver mitochondria activity in varying degrees,enhancement of oxidative phosphorylation,but for type 2 diabetes mice,the increase of liver mitochondria activity is milder.Both type 1 and type 2 diabetes mice have no significant change of liver mitochondria activity at different stages of diabetes.This indicates that at the early stage of type 1 and type 2 diabetes,liver plays a great role in regulation,while skeletal muscle does not.And at end-stage of type 2 diabetes,liver mitochondria will functionally decompensate little by little.