Study Of Obesity Induced Metabolic Syndrome Promotes Urinary Voiding Dysfunction In Mice

Backgrounds: Over the years, obesity is dramatic increase around the world, which is a leading preventable cause of death worldwide, with increasing rates in adults and children.Obesity is a medical condition in which excess body fat/ triglyceride has accumulated to the extent that it may have a negative effect on health, leading to reduced life expectancy and/or increased health problems. It could be extended to simply/primary and secondary obesity in etiology, 95% obesity turn out to be the simply obesity and be associated with genetic, diet and physical activity. Obesity was not only limited in western developed countries and be reported an increased tendency to morbidity and mortality in developing countries with rapidly life style and diet changed. It showed that the ratio of overweight in China had reached 20-30% and even 35-40% in urban citizens since 90 decades of last century. The majority remain did not show enough respects and thus made several obesity related diseases more common, such as heart disease, type 2 diabetes, obstructive sleep apnea, certain types of cancer, and osteoarthritis etc.Metabolic syndrome(Met S) was proposed as an umbrella term to include subjects affected by cardiovascular and metabolic risk factors, such as visceral obesity, hypertension, hyperglycemia, low high-density lipoprotein cholesterol(HDL-C) and hypertriglyceridemia, in the effort to identify a diagnostic category able to predict cardiovascular-metabolic complications. The prevalence of Met S also affect around 34–39% of the adult population in the USA.Benign prostatic hyperplasia(BPH) also is the most common benign neoplasm in aged men, marked by the progressive development of lower urinary tract symptoms(LUTS).Obesity, body size and composition have long been hypothesized to be influence the risk of LUTS and BPH; a cluster of published evidence demonstrated that body weight, body mass index(BMI), central obesity measured by waist circumference may increase the risk of BPH and LUTS. The pathogenesis and explanations gleaned from systemic inflammation, oxidative stress to metabolic syndrome. However, there is no definitive information provided.One recent notion is that the Met S might be linked to BPH, LUTS, overactive bladder(OAB) and erectile dysfunction(ED) also some clinical conditions in urology.Although the molecular pathways potentially linking BPH and Met S are not yet completely defined, some studies have suggested a feasible association between Met S and LUTS related to BPH, with probably new targets for prevention and treatment of these disorders. However, research into the link between the Met S and these clinical conditions has been going on for a shorter period of time, nor the animal model has been established to explore the link between obesity or Met S towards LUTS, definitive evidence is still sparse. Better understanding of animal models will lead to a better investigation on molecular part and prophylaxis treatment and prevention of diseases. The aim of work is thus to use ob/ob mice to establish a valid animal model in order to examine the manifest of Met S towards urological complications and the relationship between the obesity, Met S and LUTS and potential risk factors for LUTS from animal model view. We hypothesize that Met S play an important role in the etiology on BPH and LUTS, which could be used as a proxy to predict for BPH and LUTS in human.Objective: 1. Using ob/ob mice to establish a valid animal model to observe the features of obesity induced Met S and evaluated urological complications via urodynamic trials.2. The potential correlations, risk factors and molecular pathway for Met S related LUTS were conducted to provide basic evidences to clinical findings.Materials and methods: 1. The control group(C57BL/6N mice) and obesity group(B6.V-Lepob/J, obob mice) were maintained on regular diet for 28 weeks. Animals were subjected to the assessment of body weight(BW), body length(BL), waist circumference(WC), body mass index(BMI), blood glucose(BG), plasma insulin(INS), plasma leptin(LEP), total cholesterol(CHO), free fatty acid(FFA) on different time points.2. Twenty-four-hour voiding frequency and volume measurement and conscious cystometrogram were performed to assess the voiding function of animal models.3. MRI image analysis was performed to evaluate the development of prostate hyperplasia and fat distributions.4. Pearson correlation analysis was used to evaluate the correlation of the Met S parameters and voiding frequency.5. Western blot and immunohischemistry(IHC) were thus performed after mice sacrificed on 28 weeks;Results: 1. Obesity parameters such as BW, WC, and BMI were significantly higher in B6.V-Lepob/J mice compared to C57BL/6N mice.(p<0.01) Higher levels of BG, INS, total CHO and FFA were noted in B6.V-Lepob/J mice than C57BL/6N mice(p<0.05);2. Frequency, lower average urine volume and baldder capacity, basic and peak bladder pressures and other urinary voiding dysfunctions were significant noted in B6.V-Lepob/J mice.(p<0.05)3. MRI assessments demonstrate marked increase in peritoneal fat and prostate volume.4. The regression and correlation analysis indicate that peritoneal fat(R=0.853; p<0.05), CHO(R=0.729; p<0.001), BG(R=0.712; p<0.01) and prostate volume(R=0.706; p<0.05) strongly correlate with LUTS whereas BMI, WC, BMI, INS, and FFA moderately correlate with the prevalence of voiding dysfunction.5. Histology of prostate in B6.V-Lepob/J mice showed increased gland crowding and infiltration of immune cells in the stroma, compared to C57BL/6N mice.Conclusion: 1. Leptin deficient B6.V-Lepob/J mice could be employed as a novel animal model to Met S.2. B6.V-Lepob/J mice could be induced LUTS, which manifested as frequency and other voiding disfunctions, these findings were concurrent with Met S components and peritoneal fat widely distributions3. The BG, INS, prostate volume and fat volume might be the risk factor of LUTS, and BG was indicated to be the independent risk factor for LUTS.Backgrounds: Stress urinary incontinence(SUI) is a common disease that is de?ned as the involuntary leakage of urine under vesical stress conditions such as coughing and sneezing. It might associate to denervation damage, ischemia and mechanical injuries to the muscular, nervous and connective components of the lower urinary tract tissues. Although it might have a good prognosis, it could affect basic psychology health such as autism, depressing, etc. Many patients of SUI rejected to clinic with a “just live with” attitude, also inducing autism and depressing. There are four main types of incontinence: Urge incontinence due to an overactive bladder, Stress incontinence due to poor closure of the bladder, mix incontinence due to either poor bladder contraction or blockage of the urethra, Functional incontinence due to medications or health problems making it difficult to reach the bathroom. it has been reported that the prevalence of urinary incontinence in women increases during young adult life(20% to 30%), reaches a broad peak around middle age(30% to 40%), and then increases steadily in elderly people(30% to 50%). Risk factors for female SUI include parity, aging and obesity, as well as parturition associated injuries to muscles, connective tissues and nerves. In additional, the ischemia of pelvic tissue, in most cases, would indicate to have a relation to the oxidative stress and exacerbate the SUI.Under most normal condition, there existed several sorts of antioxidant and oxidation to maintain the oxidative balance. Oxidation reactions can produce free radicals and be inhibited by antioxidant. When the inflammation occurs, protease would activate the oxidation reactions and cause damage or death to the cell. Basically, there are 2 types of antioxidants, such as enzymes such as superoxide dismutase, catalase, as well as glutathione,vitamin C, vitamin A, and vitamin E and various peroxidases. Three forms of superoxide dismutase are present in humans: SOD1, SOD2 and SOD3, which played an important role in disease and often be used as one of the most reliable antioxidant parameter in research.Long term high-caloric and fat diet would induce obesity, hyperglycemia and glucose intolerance and increased serum triglycerides, which might reduce the resistance to inflammation and oxidative stress. A cluster of evidences had showed that SUI is related to birth trauma, however, the definitive information about the role of oxidative stress response to birth traumatic SUI in animal model does not well provided clearly and further study is expected.Objective: The purpose of the present study was, therefore, to assess the effects of Mn SOD deficiency in urethral smooth muscles to determine the underlying role of oxidant stress in SUI.Materials and methods: 1. Knock out(KO) mice: The colony of smooth muscle-specific Mn SOD knockout mice used in the study was generated by Cre-Lox P crossbreeding technique. Polymerase Chain Reaction(PCR) and immunohistochemery(IHC) were employed to identify the genotype of offspring mice. Mice met a criterion of genotype were included(n=48), the same quantity control mice were set as control group(n=48).2. Control and KO Mice were set 4 subgroups on 12 weeks in progress, which breeding by high fat diet(HFD, 80% fat) and regular diet(RD) to 24 weeks, basic information of obesity, including body weight(BW), waist circumference(WC), body mass index(BMI), blood glucose(BG) and tolerances test(GTT) were observe and calculated.3. Vaginal distention(VD) was preformed at the end of the 24 weeks by using 6-Fr. Foley catheter balloon. The leak point pressure(LPP) were measured at 4,10 and 20 days postsugery;4. In vitro experiments( Western blots and IHC)Results: 1. Mn SOD gene were knock out by Cre-Lox P technique, which identified by PCR and IHC results;2. HFD mice gain more BW, WC and BMI, also increasing BG and abnormal GTT than normal diet mice, whereas no significant differences found between control and KO of same diet in taken.3. The LPP level were found the lowest in HFD+KO group compared to other groups at 4 and 10 days post-VD; the highest LPP level existed in control+ND group, which were recovered on 10 days after surgery, compared to other groups’ 20 days recovery.4. Anti-oxidative enzymes in HFD group, especially Mn SOD, showed a lower lever express than control mice, which would elevate to normal level at 10 days after surgery.Conclusions: 1. Cre-Lox P crossing breeding could be employed to gain the Mn SOD Specific knock out mice;2. HFD could induce the metabolic syndromes, such as obesity, high glucose and insulin resistance.3. LPP level after VD would decrease if Mn SOD were knocked out in smooth muscle, and this effect could be exacerbated by long term HFD feeding.4. Mn SOD and antioxidant might play an important role in SUI mechanism.