Testicular biodistribution of 450 nm fluorescent latex particles after intramuscular injection in mice

The significant expansion in the use of nanoparticles and submicron particles during the last 20 years has led to increasing concern about their potential toxicity to humans and particularly their impact on male fertility. Currently, an insufficient number of studies have focused on the testicular biodistribution of particles. The aim of our study was to assess the distribution of 450 nm fluorescent particles in mouse testes after intramuscular injection. To this end, testes were removed from 5 groups of 3 mice each at 1 h (H1), 4 days (D4), 21 days (D21), 45 days (D45) and 90 days (D90) after the injection of 7.28 × 10⁹ particles in the tibialis anterior muscles of each mouse. We examined histological sections from these samples by epifluorescence microscopy and confocal microscopy and identified testicular biodistribution of a small number of particles in groups H1, D4, D21, D45 and D90. Using CD11b immunostaining, we showed that particles were not carried into the testis by macrophages. The intratesticular repartition of particles mainly followed testicular vascularization. Finally, we found some particles in seminiferous tubules but could not determine if the blood-testis barrier was crossed.

Size of submicrometric and nanometric particles affect cellular uptake and biological activity of macrophages in vitro

BACKGROUND

Micrometric and nanometric particles are increasingly used in different fields and may exhibit variable toxicity levels depending on their physicochemical characteristics. The aim of this study was to determine the impact of the size parameter on cellular uptake and biological activity, working with well-characterized fluorescent particles. We focused our attention on macrophages, the main target cells of the respiratory system responsible for the phagocytosis of the particles.

METHODS

FITC fluorescent silica particles of variable submicronic sizes (850, 500, 250 and 150 nm) but with similar surface coating (COOH) were tailored and physico-chemically characterized. These particles were then incubated with the RAW 264.7 macrophage cell line. After microscopic observations (SEM, TEM, confocal), a quantitative evaluation of the uptake was carried out. Fluorescence detected after a quenching with trypan blue allows us to distinguish and quantify entirely engulfed fluorescent particles from those just adhering to the cell membrane. Finally, these data were compared to the in vitro toxicity assessed in terms of cell damage, inflammation and oxidative stress (evaluated by LDH release, TNF-α and ROS production respectively).

RESULTS AND CONCLUSION

Particles were well characterized (fluorescence, size distribution, zeta potential, agglomeration and surface groups) and easily visualized after cellular uptake using confocal and electron microscopy. The number of internalized particles was precisely evaluated. Size was found to be an important parameter regarding particles uptake and in vitro toxicity but this latter strongly depends on the particles doses employed.

Mise au point d’un modèle d’étude des effets d’une cryothérapie sur des tumeurs pulmonaires

Adenocarcinomas are today the most frequent lung cancers. They are mainly treated by surgery or by chemotherapy, but for the most advanced stages a local cryotherapy can be proposed as a palliative option for bronchial desobstruction.

AIM OF THE STUDY

The aim of this work was to establish an experimental model to study in vivo the biological effects of this technique to propose it as a neoadjuvant treatment.

MATERIALS AND METHODS

A xenograft system was used: cells from the A549 cell line were injected subcutaneously into SCID mice. Tumour nodes could be treated after seven weeks. The histological study showed that these tumours faithfully reproduced the morphological features of adenocarcinoma, and developed an intratumoral neovascularization. Two protocols of cryotherapy (1 vs 3 cycles of freezing) were performed and the induction of apoptosis was analyzed by immunohistochemical staining of cleaved caspase-3.

RESULTS

The basal expression of cleaved caspase-3 in untreated tumours (23%) increased after cryotherapy. The increase was maximal eight hours after treatment (up to 47% of positive cells) and was less important with the first protocol, suggesting a lesser efficiency in the induction of apoptosis.

CONCLUSION

The establishment of this model, which is faithful to physiological features, allowed us to demonstrate in vivo time and dose-dependent effects of cryotherapy.

Cytokine mRNA expression in mouse colon: IL-15 mRNA is overexpressed and is highly sensitive to a fibre-like dietary component (short-chain fructo-oligosaccharides) in an Apc gene manner

On the basis of studies using the Min mouse model of colon carcinogenesis, we have recently proposed that a fibre-like food (short-chain fructo-oligosaccharides, sc-FOS) fermented in the colon may stimulate a mechanism of cancer immunosurveillance. In the present paper, we have investigated the expression of cytokines as potential effector molecules. Interleukin (IL-)4, IL-5, IL-13, IL-15 and interferon (INF)-gamma mRNAs were detected by a multi-probe ribonuclease protection assay in C57BL/6J and Min mouse colons. IL-15 mRNA expression was significantly amplified (P=0.01) by the sc-FOS-enriched diet in the colon of Min mice.