大鼠膀胱病變的機轉及治療策略

Abstract

膀胱的主要功能是暫存和協助排尿。糖尿病是一種代謝性疾病，會導致許多並發症，包括糖尿病膀胱功能障礙和下泌尿道症狀。與普通人群相比，糖尿病患者中風的風險是普通人群的兩倍。中風是一種疾病，其病因為流向大腦的血流不暢所導致。尿失禁通常是急性半球中風的後遺症。另一方面，環磷酰胺是臨床上用於治療腫瘤疾病的化療藥物。然而，其有毒代謝物會導致出血性膀胱炎和膀胱過度活動。Exendin-4 (Ex-4) 是一種腸促胰島素藥物，已獲准用於糖尿病治療和神經元保護。然而，臨床上需要頻繁注射該藥限制了其應用。我們製備了含有Exendin-4的奈米顆粒 (Ex-4-loadedpoly (d,l-lactide-co-glycolide) nanoparticles, PEx-4) 並研究了對糖尿病大鼠的腦缺血/再灌注誘發的腦損傷和排尿功能障礙的影響。使用鏈脲佐菌素 (streptozotocin) 誘導的第一型糖尿病大鼠進行雙側頸動脈閉塞10分鐘的腦缺血模型，我們比較了Ex-4和PEx-4 對前額葉皮層水腫、排尿功能和氧化壓力的影響，並利用免疫組織化學染色來評估對細胞凋亡、細胞焦亡與細胞自噬作用的影響。電針 (Electroacupuncture, EA) 是一種流行的針灸療法，在傳統經絡理論的基礎上，將針插入體內的穴位並進行最小的電刺激，其中以BL33 (中髎穴，位於人體腰骶部，第三骶後孔中，大鼠則為第二骶後孔中) 為臨床治療中最常用的經絡穴位。我們在環磷酰胺誘導的排尿功能障礙大鼠中使用電針治療評估膀胱中的排尿變化。內源性大麻素主要通過與外周組織、脊髓和大腦中的 G 蛋白偶聯受體、大麻素受體 1型和 2 型結合來抑制傷害感受。兩種大麻素受體也已在小鼠、大鼠、猴子和人類的膀胱中被發現。我們在環磷酰胺誘導的排尿功能障礙大鼠中探討AM251（一種大麻素受體 1型拮抗劑）評估膀胱中的排尿變化。結論，具有更強抗氧化活性和持久生物利用度的 PEx-4 通過抑製糖尿病大鼠的氧化壓力、內質網壓力、細胞凋亡、細胞自噬和細胞焦亡信號傳導，有效改善腦缺血/再灌注誘發的腦部和膀胱損傷。另外，電針治療和AM251（一種大麻素受體 1型拮抗劑）可改善 CYP 誘導的大鼠模型中的排尿功能障礙。The major functions of urinary bladder are temporary storage and assistance in the expulsion of urine. Diabetes mellitus (DM) is a metabolic disorder which leads to many complications including diabetic bladder dysfunction and lower urinary tract symptoms. The risk for stroke is twice as much in DM patients by comparison with the general population. A stroke is a medical condition in which poor blood flow to the brain causes cell death. Urinary incontinence is a sequela of acute hemispheric stroke commonly. In addition, Cyclophosphamide (CYP) is a chemotherapy agents clinically used to treat tumor diseases. However, its toxic metabolite causes hemorrhagic cystitis and bladder hyperactivity.Exendin-4 (Ex-4) is an incretin mimetic peptide accepted for neuronal protection and diabetes treatment. Nevertheless, the required frequent injections put a limit on its clinical use. Ex-4-loaded poly (d,l-lactide-co-glycolide) nanoparticles (PEx-4) was prepared to investigate the effect on cerebral ischemia/reperfusion (IR) injury associated with cystopathy in diabetic rats. By using ten minutes of bilateral carotid artery occlusion combined with hemorrhage-induced hypotension of IR model in streptozotocin-induced type 1 diabetic (T1DM) Wistar rats, we compared PEx-4 and Ex-4 effect on voiding function, prefrontal cortex edema and oxidative stress including cerebral spinal fluid (CSF) reference HOCl (RHOCl) and H2O2 (RH2O2) levels, endoplasmic reticulum (ER) stress, autophagy, apoptosis and pyroptosis signaling in brain and bladder by immunohistochemistry and western blotting.Electroacupuncture (EA) is a popular acupuncture therapy, in which needles are inserted into acupuncture points within the body and a minimal electric stimulation based on traditional meridian theory. We explore Electroacupuncture treatment in CYP-induced bladder dysfunction rats to evaluate the functional alterations of the bladder.Endocannabinoids inhibit nociception primarily by binding to G-protein coupled receptors, cannabinoid receptors 1 (CB1) and 2 (CB2) , in peripheral tissue, spinal cord and brain. CB1 and CB2 have also been identified in the bladders of mice, rats, monkey and humans. We explore the treatment with AM251 (a CB1 antagonist) in CYP-induced bladder dysfunction rats to evaluate the functional alterations of the bladder.Subcutaneous administration of PEx-4 displayed long-lasting hypoglycemic effect and higher CSF antioxidant activity than Ex-4 in rats. Our results showed that T1DM enhanced CSF RH2O2, and pIRE-1/pJNK/cleaved caspase-12/CHOP- mediated ER stress, PARP /caspase 3 mediated apoptosis, LC3-II/Beclin-1 mediated autophagy and IL-1β/caspase 1 mediated pyroptosis signaling in the rat bladders and prefrontal cortex. IR caused damage in micturition center, prefrontal cortex edema and further enhanced CSF HOCl and RH2O2 level, ER stress, autophagy, apoptosis and pyroptosis signaling in the T1DM brains and bladders. PEx-4 were more efficient than Ex-4 in attenuating IR-evoked oxidative stress and prefrontal cortex edema in brains and improving voiding dysfunction in bladders of T1DM rats. EA treatment and the treatment with AM251 in CYP-induced rats recovers bladder dysfunctions including intercontraction interval (ICI) , and bladder compliance.In summary, PEx-4 with long-lasting bioavailability and stronger antioxidant activity confer efficiently therapeutic efficacy to ameliorate IR-evoked brain and bladder injury through inhibiting oxidative stress, ER stress, autophagy, apoptosis and pyroptosis signaling in diabetic rats. Electroacupuncture treatment and the treatment with AM251 also improve bladder dysfunction in CYP-induced rat model.