Background: Bladder cancer poses a great burden on society and its high rate of recurrence and treatment failure necessitates use of appropriate animal models to study its pathogenesis and test novel treatments. Orthotopic models are superior to other types since they provide a normal microenvironment. Four methods are described for developing bladder cancer models inside the animal's bladder. Direct intramural injection is one of these methods and is widely used. However, its efficacy in model development has not yet been studied. We aimed to evaluate the efficacy and success rate of the direct intramural injection method of developing an orthotopic model for the study of bladder cancer.Method: Tumor cell lines were prepared in four microtubes. Aliquots of 200 × 10 3 cells were injected through a 27 gauge needle into the ventral wall of the bladders of 4 male and 4 female BALB/c mice following a midline 1 cm laparotomy incision. In addition, 1 million cells from each microtube were injected into the flanks of control mice.To prevent infection and alleviate pain, 5 mg/kg enrofloxacin and 2.5 mg/kg flunixin meglumine, respectively, were injected subcutaneously. Results:Tumors formed in all mice, resulting in 100% take rate and zero post-operation mortality. Surgery time was ≤15 min per mouse. In two mice, tumors were found in the peritoneal space as well. Conclusion:Direct intramural injection is a rapid, reliable, and reproducible method for developing orthotopic models of bladder cancer. It can be done on both male and female mice and only requires readily available surgical tools. However, needle track can result in cell spillage and peritoneal tumors.

No abstract

Background: This study was conducted to investigate the effects of intravitreal injection of bone marrow mononuclear stem cells (BMMNC) on neurological and vascular damages in a rat model of retinopathy of prematurity (ROP). Methods: Ten newborn Wistar rats were divided randomly into the control and the oxygen-induced retinopathy (OIR) group. Animals in the OIR group were incubated in an oxygen chamber to induce retinopathy. One eye of animals in the OIR group received BMMNC suspension (treated eyes), and the contralateral eye received the same volume of saline injection. Then, all animals underwent funduscopy, electroretinography, and histopathological assessments. Results: Compared to the saline injection group, eyes treated with BMMNC had less vascular tortuosity while veins and arteries had relatively same caliber, as revealed by fundus examination. Eyes in treatment group showed significantly elevated photopic and scotopic B waves amplitude. In histopathological assessments, nuclei count in inner retinal layer in the treatment group was significantly lower compared to untreated eyes. Also, BMMNC transplantation reduced apoptosis of neural retina cells. Conclusions: Our results indicated that intravitreal injection of BMMNC reduces neural and vascular damages and results in recovered retinal function in rat model of ROP. Ease of extraction without in vitro processing, besides the therapeutic effects of BMMNCs, make this source of stem cells as a new choice of therapy for ROP or other retinal ischemic diseases in further biomedical research.