Gugliandolo Enrico, Franco Gianluca Antonio, Marino Ylenia, Peritore Alessio Filippo, Impellizzeri Daniela, Cordaro Marika, Siracusa Rosalba, Fusco Roberta, D'Amico Ramona, Macrì Francesco, Di Paola Rosanna, Cuzzocrea Salvatore, Crupi Rosalia
Department of Veterinary Science, University of Messina, Messina, Italy.
Department of Chemical, Biological, Pharmaceutical and Environmental Science, University of Messina, Messina, Italy.
Front Vet Sci. 2024 Jan 4;10:1327102. doi: 10.3389/fvets.2023.1327102. eCollection 2023.
Feline idiopathic cystitis is a common, chronic-relapsing disorder of the lower urinary tract. In addition to environmental modification/enrichment, long-term and safe treatment targeting specific pathophysiological changes may be of help. In this context, effective dietary interventions hold clinical promise. Palmitoyl-glucosamine (PGA) and hesperidin (HSP) are safe and authorized feed ingredients for animal nutrition under European regulations.
The current study aimed to investigate whether a 3:1 mixture of micronized PGA and HSP could represent a novel mechanism-oriented approach to chronic cystitis management. A newly validated rat model of cyclophosphamide (CYP)-induced chronic cystitis was used (40 mg/kg, three intraperitoneal injections every 3rd day). Animals were randomized to orally receive either vehicle or PGA-HSP at a low (72 + 24 mg/kg) or high (doubled) dose for 13 days, starting 3 days before the chronic CYP protocol, with mesna (2-mercaptoethane-sulfonate) being used as a reference drug.
Higher PGA-HSP dose was effective at relieving chronic visceral pain, as measured by mechanical allodynia test (von Frey test). The severity of cystitis was also significantly improved, as shown by the reduced sonographic thickening of the bladder wall, as well as the decrease in edema, bleeding and bladder to body weight ratio compared to the vehicle treated group. A significant decrease of MPO activity, MDA level and fibrosis at Masson's trichrome staining was also observed in animals administered PGA-HSP in comparison to vehicle treated ones. The CYP-induced increase in bladder mRNA expression of pro-inflammatory cytokines was also significantly counteracted by the study mixture. Moreover, CYP-induced bladder mast cell accumulation and releasability were significantly decreased by PGA-HSP (even at the low dose), as determined by metachromatic staining, chymase and tryptase immunostaining as well as enzyme-linked immunosorbent assay for histamine and 5-hydoxytriptamine.
PGA-HSP is able to block CYP-induced decrease of tight junction proteins, claudin-1 and occludin, thus preserving the urothelial bladder function. Finally, neuroinflammatory changes were investigated, showing that dietary supplementation with PGA-HSP prevented the activation of neurons and non-neuronal cells (i.e., microglia, astrocytes and mast cells) at the spinal level, and counteracted CYP-induced increase of spinal mRNA encoding for pro-inflammatory cytokines. Altogether, the present findings confirm the uroprotective and pain-relieving effect of PGA-HSP and pave the way to potential and relevant clinical applications of the study supplement in feline idiopathic cystitis.
猫特发性膀胱炎是下尿路常见的慢性复发性疾病。除了环境改善/优化外，针对特定病理生理变化的长期安全治疗可能会有所帮助。在这种情况下，有效的饮食干预具有临床前景。根据欧洲法规，棕榈酰葡萄糖胺（PGA）和橙皮苷（HSP）是动物营养中安全且已获批准的饲料成分。
本研究旨在调查微粉化PGA和HSP的3:1混合物是否可代表一种针对慢性膀胱炎管理的新型机制导向方法。使用一种新验证的环磷酰胺（CYP）诱导的慢性膀胱炎大鼠模型（40mg/kg，每3天腹腔注射3次）。动物被随机分为口服载体或低剂量（72 + 24mg/kg）或高剂量（加倍）的PGA - HSP，持续13天，从慢性CYP方案前3天开始，美司钠（2 - 巯基乙烷磺酸盐）用作参考药物。
通过机械性异常性疼痛测试（von Frey测试）测量，较高剂量的PGA - HSP可有效缓解慢性内脏疼痛。膀胱炎的严重程度也显著改善，表现为膀胱壁超声增厚减少，以及与载体处理组相比，水肿、出血和膀胱与体重比降低。与载体处理组相比，给予PGA - HSP的动物在Masson三色染色中MPO活性、MDA水平和纤维化也显著降低。研究混合物还显著抵消了CYP诱导的膀胱促炎细胞因子mRNA表达增加。此外，通过异染性染色、糜酶和组织蛋白酶免疫染色以及组胺和5 - 羟色胺的酶联免疫吸附测定确定，PGA - HSP（即使在低剂量）显著降低了CYP诱导的膀胱肥大细胞积累和释放能力。
PGA - HSP能够阻断CYP诱导的紧密连接蛋白claudin - 1和occludin的减少，从而保留膀胱尿路上皮功能。最后，研究了神经炎症变化，表明用PGA - HSP进行饮食补充可防止脊髓水平的神经元和非神经元细胞（即小胶质细胞、星形胶质细胞和肥大细胞）激活，并抵消CYP诱导的脊髓促炎细胞因子编码mRNA增加。总之，本研究结果证实了PGA - HSP的尿路保护和止痛作用，并为该研究补充剂在猫特发性膀胱炎中的潜在及相关临床应用铺平了道路。
