The current work is focused on the study of optical clearing of skeletal muscles under local compression. The experiments were performed on in vitro bovine skeletal muscle. The time dependence of optical clearing was studied by monitoring the luminescence intensity of NaYF4: Er,Yb upconverting particles located under tissue layers. This study shows the possibility to use upconverting nanoparticles (UCNPs) both for studying the dynamics of the optical clearing of biological tissue under compression and to detect moments of cell wall damage under excessive pressure. The advantage of using UCNPs is the presence of several bands in their luminescence spectra, located both at close wavelengths and far apart.

Malignant gliomas are highly invasive tumors that use the cerebral vessels for invasion due to high vascular fragility of the blood–brain barrier (BBB). On one hand, glioma is characterized by the BBB disruption, on the other hand, drug brain delivery via the BBB is a big challenge in glioma therapy. The limited information about vascular changes associated with glioma growth is a reason of slow progress in prevention of glioma development. Here, we present in vivo and ex vivo study of the BBB disruption and glioma cells (GCs) migration in rats using fluorescence and confocal microscopy. We uncovered a local breach in the BBB in the main tumor mass but not within the border of normal and malignant cells, where the BBB was impermeable for high weight molecules. The migration of GCs were observed via the cerebral vessels with the intact BBB that was associated with macrophages infiltration. The mechanisms underlying glioma progression remain unknown but there is an evidence that the sympathetic nervous system (SNS) via activation of vascular beta2-adrenoreceptors (B2-ADRs) can play an important role in tumor metastasis. Our results clearly show an increase in the expression of vascular B2-ADRs and production of the beta-arrestin-1 - co-factor of B2-ADRs signaling pathway in rats with glioma. Pharmacological blockade of B2-ADRs reduces the BBB disruption, macrophages infiltration, GCs migration and increases survival rate. These data suggest that the blockade of B2-ADRs may be a novel adjuvant therapeutic strategy to reduce glioma progression and prevent metastasis.

Neonatal stroke is similar to the stroke that occurs in adults and produces a significant morbidity and long-term neurologic and cognitive deficits. There are important differences in the factors, clinical events and outcomes associated with the stroke in infants and adults. However, mechanisms underlying age differences in the stroke development remain largely unknown. Therefore, treatment guidelines for neonatal stroke must extrapolate from the adult data that is often not suitable for children. The new information about differences between neonatal and adult stroke is essential for identification of significant areas for future treatment and effective prevention of neonatal stroke. Here, we studied the development of stress-induced hemorrhagic stroke and possible mechanisms underlying these processes in newborn and adult rats. Using histological methods and magnetic resonance imaging, we found age differences in the type of intracranial hemorrhages. Newborn rats demonstrated small superficial bleedings in the cortex while adult rats had more severe deep bleedings in the cerebellum. Using Doppler optical coherent tomography, we found higher stress-reactivity of the sagittal sinus to deleterious effects of stress in newborn vs. adult rats suggesting that the cerebral veins are more vulnerable to negative stress factors in neonatal vs. adult brain in rats. However, adult but not newborn rats demonstrated the stroke-induced breakdown of blood brain barrier (BBB) permeability. The one of possible mechanisms underlying the higher resistance to stress-related stroke injures of cerebral vessels in newborn rats compared with adult animals is the greater expression of two main tight junction proteins of BBB (occludin and claudin-5) in neonatal vs. mature brain in rats.