Morphometric characteristics of the structural components of the intervertebral disc in rats at different times of the experimental opioid exposure and after its withdrawal

Background. The world and domestic literature from time to time report about the problems of uncontrolled drug abuse. This problem is associated not only with the negative impact on the morphological structure, but also is a serious factor which, if it has been exposing for a long time, leads to disability and death. Despite a significant number of studies in this area, the problem of changes in the morphometric parameters of the intervertebral disc’s structural components under chronic exposure of opioid agents still remains unresolved. That is why the study of morphometric characteristics of the intervertebral disc’s structural components under experimental opioid exposure will be interesting for both - morphologists and practical traumatologists. Objective. To study the morphometric parameters of the structural components of the intervertebral disc in rats at different times of the experimental opioid exposure and after its withdrawal. Methods. The objects of the study were 61 mature outbred male rats, weight - 80-135g, age - 4.5-7.5 months. Animals were injected with nalbuphine intramuscularly once daily (at 10-11 am) for 42 days. Histological specimens were stained with alcyan blue (for the study of the collagen fibers thickness of the anterior and posterior longitudinal ligaments) and PAS-reaction (for the study of the gelatinous nucleus and its capsule thickness). For measurements of collagen fiber thickness, were taken images at x100 magnification, for measurements of the gelatinous nucleus and its capsule thickness - at x40 magnification. Measurements were performed with ImageJver software. 1.51 using the tool "straight" for linear measurements. Results. Thus, changes in the collagen fibers thickness of the anterior and posterior longitudinal ligaments during the experiment were uneven and had different tendencies. The thickness of the posterior longitudinal fibers changed mostly within the central trend of the control group with a significant decrease only at the 2nd, 3rd, and 4th weeks. However, more significant, as for pathogenetic changes, was a sharp decrease in the number of fibers thicker than 25 μm in animals of the experimental group after 2 weeks of the study, and the maximum thickness at 5th and 6th week was only 31.41 μm and 35.24 μm whereas the maximum thickness of the control group was 81.48 μm. In the withdrawal group, only a decrease in sites with nuclear edema can be considered positive, which is displayed by morphometrical decrease in the maximum value, but the central trend remains much lower than in the control group, which also indicates the predominance of decompensatory changes. Conclusion. During the whole experiment, we observed similar changes in the nucleus capsule thickness: non-systemic fluctuations of the central parameters ​​up to the 5th week and a sharp decompensation at the 6th week, which was manifested by a sharp decrease in thickness. Simultaneously, we observed numerous sites of edema and thickening by more than 100 μm on the 2nd week. Despite a general decrease in median and quartile at this time, such sites were also noted at the 6th week. Thickness of the nucleus capsule in the withdrawal group did not demonstrate significant dynamics and remained similar to those at the 6th week. Although, this can be interpreted as the stabilization at a certain level without further negative dynamics.

Morphological and morphometric adaptations of testes in broilers induced by glucocorticoid

Glucocorticoids (GCs) cause excess fat accumulation, which leads to fertility dysfunction in broilers. The study investigated alterations in the morphology and morphometry of the testes of broilers in response to GC and dexamethasone (DEX). Male day-old chicks were randomly divided into a control group and three experimental groups (E1, E2, and E3). The control group was fed a commercial broiler ration. The experimental groups were fed a commercial broiler ration containing GC (i.e. DEX 3, 5, and 7 mg/kg, respectively). The testes were collected and stained with haematoxylin and eosin to count the number of testicular seminiferous tubules. An increase in the seminiferous tubule count was initially seen, which declined as both the age of the broilers and the dose of DEX increased. Morphometric measurements, i.e., the testicular capsule thickness, seminiferous tubule diameter, and seminiferous epithelium height, were performed. The initial thickening of the testicular capsule was evident. There was a depletion of the interstitial (Leydig) cell population in the experimental groups with the age and increased with the dose advancement. The diameter of the seminiferous tubules and testicular capsule thickness remained upregulated in the treatment groups with the increased dose of DEX. The initial height of the seminiferous epithelium increased in the experimental groups of broilers. The study suggests that DEX greatly alters the morphological architecture of broiler testes; as a result, it could be said that DEX has the effect on the infertility of the broiler by affecting the morphology as well as the functionality of the testes.

Leech therapy (Hirudo medicinalis) attenuates testicular damages induced by testicular ischemia/reperfusion in an animal model

Background Testicular torsion/detorsion triggers tissue ischemia/reperfusion, leading to reactive oxygen species overgeneration and apoptosis. The saliva of leeches is full of anti-inflammatory, anticoagulants, antioxidants, and antimicrobial agents. Therefore, this study aimed to assess the protective mechanism of leech therapy on testicular ischemia/reperfusion damage. Methods 18 adult male rats were randomly divided into three groups: 1-Sham-operated group (SO). 2-Torsion/detorsion (T.D) group: two hours of testicular torsion with two hours of testicular detorsion was performed. 3-Torsion/detorsion + Leech therapy (TDL) group. Sperm parameters (motility, vitality, morphology, and concentration), oxidative stress biomarkers (MDA, CAT, GPx, and TAC), histopathological factors (Mean seminiferous tubular diameter, Germinal epithelial cell thickness, Testicular capsule thickness, Johnson’s score, and Cosentino’s score), and immunohistochemical markers for apoptosis detection (Bax, Bcl-2, and Caspase-3) were measured. Results There was a significant difference for all sperm parameters in the T. D group compared to the sham group. Leech therapy significantly increased progressive motility and normal morphology and reduced non-progressive motility. In the TDL group, MDA concentration significantly reduced, and levels of GPx, TAC, and CAT remarkably increased. All evaluated histopathological parameters in the TDL group significantly increased compared to the T. D group except for the testicular capsule thickness. T. D notably increased the expression of Bax and Caspase-3, while the treatment group slowed the rate of apoptosis compared to the control group. Bcl-2 expression in the T. D group was significantly lower than that in the sham group. Leech therapy increased the Bcl-2 expression. Conclusion Leech therapy attenuates damages to testicular tissue following torsion/detorsion due to its antioxidant, anti-inflammatory, and anti-apoptotic effects. Hence, it can be considered as an effective remedy for testicular ischemia/reperfusion. Graphical abstract

Microstructural determinants of lens stiffness in rat versus guinea pig lenses

ABSTRACTProper ocular lens function requires lens biomechanical flexibility which is lost in presbyopia during aging. As increasing lens size has been shown previously to correlate with lens biomechanical stiffness in aging, we tested the hypothesis that whole lens size determines gross biomechanical stiffness. We used an allometric approach to evaluate this hypothesis by comparing lenses from three rodent species (mouse, rats and guinea pigs) of varying size. While rat lenses are larger and stiffer than mouse lenses, guinea pig lenses are even larger than rat lenses but are softer than the rat lens. This indicates that lens size is not a sole determinant of lens stiffness and disproves our hypothesis. Therefore, we investigated the scaling of lens microstructural features that could potentially explain the differences in biomechanical stiffness between rat and guinea pig lenses, including lens capsule thickness, epithelial cell area, fiber cell widths, suture organization, and nuclear size. Capsule thickness, epithelial cell area, and fiber cell widths scaled with lens size (i.e., greater in guinea pig lenses than rats), indicating that sizes of these features do not correlate with the stiffness of rat lenses, while suture organization was similar between rats and guinea pigs. However, we found that the hard rat lens nucleus occupies a greater fraction of the lens than the guinea pig lens nucleus, suggesting a role for nuclear size in determining whole lens stiffness. Therefore, while many features contribute to lens biomechanical properties, the size of the lens nucleus with respect to the size of the lens could be a major determinant of lens stiffness in rats versus guinea pigs.