Histological and morphometrical evaluation of the urethral wall after bioresorbable stent implantation in male New Zealand White Rabbits: A preliminary study.

The aim of the study was the histological and morphometrical evaluation of the urethral wall at three time points after bioresorbable stent implantation in male New Zealand White Rabbits. The research was performed on 26 male New Zealand White rabbits aged 3-4 months and weighing 2.1-3.0 kg. Two models of bioresorbable sodium alginate-based stents were developed and implanted into the urethral lumen for one (T1), three (T3), and six weeks (T6). Sections of 5 µm thickness were cut from the urethra at intervals of 2 mm. The sliced sections were stained with hematoxylin-eosin (H&E), Van Gieson's (VG), Von Kossa, and Movat-Russell modified pentachrome (MOVAT) staining methods. The study provided valuable information for future models of urethral stents. The first model of the stent failed to fit the requirements due to inadequate mechanical properties. It curled up on itself losing the ability to adhere to the animals' urethra and was bioresorbed three weeks after implantation. The more rigid no. 2 stent was effective in widening the urethral lumen but did not biodegrade during the experiment. A comprehensive assessment of the second model's properties of biosorption and biointegration requires an extended observation of at least 12 months for an in depth morphological analysis. Stent migration is not likely to be caused solely by the mechanical properties of the urethra or urinary flow but mainly by muscle contraction of the organ wall.

Modification of a Haematoxylin, Eosin, and Natural Saffron Staining Method for The Detection of Connective Tissue.

INTRODUCTION: The aim of our study was to optimise an existing staining procedure: haematoxylin-eosin saffron (HES). The method follows the classical haematoxylin and eosin protocol with the addition of a staining step using natural saffron to better identify the collagen fibres. MATERIAL AND METHODS: The saffron solution was obtained by dissolving ground saffron stigmas in absolute alcohol. In order to test the HES method for its staining ability on four main types of collagen (I, II, III, and IV), specific tissues (skin, tooth, cartilage, aorta, spleen, and penis) were chosen. RESULTS: The procedure showed a sharp differentiation between muscle, stained red or pink, and connective tissue, stained bright yellow or orange. CONCLUSION: HES allows the diagnosis of reticulin fibrosis undetected in HE and in previous saffron staining procedures. HES represents an advantageous alternative to HE staining giving highly reproducible results with high diagnostic value.