Regulation Of Genipin On Expression Of Inflammatory Cytokines And Feeding-related Peptides In Hypothalamus In Obese Rats Induced By High-fat Diet

Objective: 1.To confirm the role of weight loss of genipin by establishing the obese rats modelinduced by high-fat diet.2.To explore the central mechanism of genipin against obesity.Methods:Male Wistar rats of clean grade(n=98,200±20g)randomly divided into the normal control group(n=15)fed with basal diet and HF group(n=83)fed with high-fat diet after adaptive feeding for one week.A measurement of body weight once a week.After 12 weeks of feeding,rats in a total of 39 were succeeded by the standard of average weight of HF group more than 20% of the average weight of the control group.We randomly divided these obese model rats into 3 groups,which were the DIO group(n=13),DIO+GL group(n=13)and DIO+GH group(n=13).All of them continued to feed with high-fat diet.We did intraperitoneal injection of genipin 7mg/kg each day in DIO+GL group and 14mg/kg each day in DIO+GH group for 10 days.We measure the bodyweight and food intake in rats everyday.After 10 days,we selected 3 from each group to do perfusion and took the brain to make frozen sections.Then we use these sections to observe the expression of NPY in rat hypothalamus by immunofluorescence staining.The remaining rats were killed.Blood was collected to detect TG,TC,LDL-C and HDL-C level in serum,and we also use ELISA to teat serum leptin level.Adipose tissues around testis,kidney and omentum was stripped to calculation the fat index of rats.Hypothalamus was taken to detect ATP level,MMP and mitochondrial ROS level,also detected TNF-?,IL-6,NPY and POMC mRNA level by RT-qPCR.Results: 1.Establishment of obese rats model induced by high-fat dietAfter feeding high-fat diet for 12 weeks,rats in a total of 39 were succeeded by the standard of it's average weight more than 20% of the average weight of the control group.2.The influence of genipin on obesity-related index of obese rats(1)Genipin reduce the bodyweight of obese ratsCompared with DIO group,after intraperitoneal injection of genipin for 10 days,the body weight of genipin in low dose group and in high dose group were significantly reduced.Compared with pretreatment,an average reduction of genipin in low dose group is 37.18±7.02g(P<0.01)and genipin in high dose group is 62.87 ±13.46g(P<0.01),suggesting that genipin can reduce body weight of DIO rats effectively.(2)Genipin reduce the food intake of obese ratsAfter intraperitoneal injection of genipin for 10 days,the food intake of genipin in low dose group and high dose group were lower than the food intake of DIO group(P<0.05).Genipin can reduce the food intake of obese rats effectively.(3)Genipin reduce the fat index of obese ratsAfter intraperitoneal injection of genipin for 10 days,compared with DIO group,the fat index of genipin in high dose group reduced by 1.78%(P<0.01).The fat mass of obese rats was reduced significantly.3.Genipin improve the serum lipid level of obese ratsSerum triglyceride levels of DIO group were higher than control group and serum HDL-C levels of DIO group were significantly lower than control group.That's showed that serum lipid levels of DIO group were disorder.After intraperitoneal injection of genipin,compared with DIO group,serum triglyceride and LDL-C levels of genipin in low dose group showed a downward trend but there was no statistically significant difference and serum HDL-C levels increased(P<0.05).Serum triglyceride levels of genipin in high dose group significantly decreased(P<0.01)and serum LDL-C levels decreased(P<0.05)and serum HDL-C levels significantly increased(P<0.01).4.Genipin decrease ATP level in obese rats hypothalamusCompared with DIO group,ATP level in hypothalamus of genipin in low dose group showed a downward trend but there was no statistically significant difference and ATP level in hypothalamus of genipin in high dose group reduced by 26.72% which suggesting that genipin in high dose group can reduce the ATP level in hypothalamus of obese rats.5.The influence of genipin on the level of mitochondrial membrane potential and ROS in rats hypothalamusThere is no difference of mitochondrial membrane potential level in hypothalamus among each group.Compared with control group,the level of mitochondrial ROS in hypothalamus of DIO group increased(P < 0.05).After the injection of genipin,compared with DIO group,the level of mitochondrial ROS in hypothalamus of genipin in low dose group and in high dose group significantly reduced(P<0.01)by 51.81% and 57.27% respectively.6.Genipin inhibit the expression of TNF-? mRNA and IL-6 mRNA in hypothalamus of ratsUse control group as a standard,the level of TNF-? mRNA and IL-6 mRNA in hypothalamus of DIO group significantly increased(P < 0.01),suggesting that DIO group have an inflammation in hypothalamus.After the intervention of Genipin,the level of TNF-? mRNA in hypothalamus of genipin in low dose group decreased(P<0.05)and the level of IL-6 mRNA showed the downward trend but was not statistically significant.The level of TNF-? mRNA and IL-6 mRNA in hypothalamus of genipin in high dose group significantly decreased(P<0.01).7.Genipin reduce the serum leptin level in obese ratsCompared with control group,serum leptin level of DIO group increased(P<0.05)known as hyperleptindemia.After the intervention of Genipin,serum leptin level of DIO group significantly decreased(P<0.01).8.The influence of genipin on the level of feeding related peptides in rats hypothalamus(1)Genipin inhibit transcription of NPY mRNA and protein expression in obese rats hypothalamusUse control group as a standard,the expression of NPY mRNA in hypothalamus of DIO group extremely increased and the expression of NPY mRNA in hypothalamus of genipin in low dose group and in high dose group significantly decreased(P<0.01).This was same with the expression of protein of each group.(2)Genipin promote transcription of POMC mRNA in obese rats hypothalamusUse control group as a standard,the level of POMC mRNA in hypothalamus of genipin in low dose group and in high dose group significantly increased(P<0.01).Conclusions: 1.By decreasing food intake of obesity rat induced by high-fat diet,genipin can reduce body weight and fat index of obese rats.2.Genipin can reduce the expression of NPY and increase the expression of POMC to inhibit food intake in hypothalamus of obese rats reduced by high-fat diet.3.Genipin can reduce the expression of TNF-? mRNA and IL-6 mRNA in hypothalamus of obese rats reduced by high-fat diet.4.By antopxidation,genipin reduced level of ROS of neuronal mitochondrion in the hypothalamus of obese rats induced by high fat diet.