Morphological changes in the pineal gland of rats under conditions of long-term exposure to bright light.

Changes in the diurnal light cycle affect the morphofunctional state of the pineal gland. The volume of the nucleus, Golgi apparatus, and mitochondria in pinealocytes decreases after 45-day exposure to bright light. After 90 days, the degree of nuclear polymorphism increased, the specific volume of the Golgi apparatus returned to normal, the volume of the granular endoplasmic reticulum decreased, while the volume of lysosomes, free ribosomes, and polysomes increased. These changes reflect plasticity of pinealocytes and adaptation of the gland to long-term 24-h light exposure.

Experimental study of millimeter wave-induced differentiation of bone marrow mesenchymal stem cells into chondrocytes.

Low power millimeter wave irradiation is widely used in clinical medicine. We describe the effects of this treatment on cultured mesenchymal stem cells (MSCs) and attempted to identify the underlying mechanism. Cells cultured using the whole marrow attachment culture method proliferated dispersedly or in clones. Flow cytometric analyses showed that the MSCs were CD90 positive, but negative for CD45. The negative control group (A) did not express detectable levels of Cbfa1 or Sox9 mRNA at any time point, while cells in the millimeter wave-induced groups (B and C) increasingly expressed both genes after the fourth day post-induction. Statistical analysis showed that starting on the fourth day post-induction, there were very significant differences in the expression of Cbfa1 and Sox9 mRNA between groups A and B as well as A and C at any given time point, between treated groups B and C after identical periods of induction, and within each treated group at different induction times. Transition electron microscopy analysis showed that the rough endoplasmic reticulum of cells in the induced groups was richer and more developed than in cells of the negative control group, and that the shape of cells shifted from long-spindle to near ellipse. Toluidine blue staining revealed heterochromia in the cytoplasm and extracellular matrix of cells in the induced groups, whereas no obvious heterochromia was observed in negative control cells. Induced cells also exhibited positive immunohistochemical staining of collagen II, in contrast to the negative controls. These results show that millimeter wave treatment successfully induced MSCs to differentiate as chondrocytes and the extent of differentiation increased with treatment duration. Our findings suggest that millimeter wave irradiation can be employed as a novel non-drug inducing method for the differentiation of MSCs into chondrocytes.

Effect of low-level Er:YAG laser irradiation on cultured human gingival fibroblasts.

BACKGROUND: Low-level laser irradiation has been reported to enhance wound healing. Activation of gingival fibroblasts (GF) has a potential for early wound healing in periodontal treatment. The present study aimed to investigate the direct effect of low-level Er:YAG laser irradiation on gingival fibroblasts proliferation in order to clarify the laser effect on healing. METHODS: Cultured human gingival fibroblasts (hGF) were exposed to low-power, pulsed Er:YAG laser irradiation with different energy densities ranging from 1.68 to 5.0 J/cm(2). The cultures were analyzed by means of trypan blue staining and counted under a light microscope. The effect of Er:YAG laser on hGF was also evaluated using a transmission electron microscope (TEM). RESULTS: Cultures irradiated with Er:YAG laser presented faster cell growth when compared with untreated controls. This difference was statistically significant. Transmission electron microscopy revealed rough endoplasmic reticulum, prominent Golgi complexes, and mitochondria after laser irradiation. CONCLUSIONS: Our results showed that the low-level Er:YAG laser irradiation stimulates the proliferation of cultured gingival fibroblasts. The optimal stimulative energy density was found to be 3.37 J/cm(2). This result suggests that Er:YAG laser irradiation may be of therapeutic benefit for wound healing.

Radioprotection of the murine submandibular gland by isoproterenol: autoradiography study with 3H-leucine.

Irradiation of the salivary glands results in the generation of free radicals from metal ions present in the secretory granules of acinar cells, a process that is believed to exacerbate radiation damage to the salivary glands. We therefore conducted a comparative investigation of radiation damage to the acinar cells of murine submaxillary glands in which granule secretion had been induced, and used autoradiography to visualize the pathological changes. Male BALB/c mice, at 8 weeks of age, were divided into four groups: a no-isoproterenol (IPR) and no-irradiation group (group I), a no-IPR, irradiated group (group II), an IPR, no-irradiation group (group III), and an IPR, irradiated group (group IV). Intraperitoneal injections of IPR were used, and 3 h later, the submaxillary region was irradiated with X-rays at a dose of 10 Gy. Three days after the irradiation, 3H-leucine was administered, and submaxillary glands were removed at predetermined times. Thin sections were prepared, and light- and electron-microscope autoradiography was performed. The number of reduced silver particles per unit acinar cell area was determined by light-microscopic autoradiography, and the proportion of reduced silver particles in the rough endoplasmic reticulum, the Golgi apparatus, and secretion granules was determined by electron-microscopic autoradiography. The result indicated that the effects of the radiation on the secretory potential of the submaxillary glands were diminished in acinar cells with a higher secretory granule content.

[Structural changes in the granular duct epitheliocytes and terminal areas of the submandibular glands induced by exposure to light and radiation in rats]. / Strukturnye izmeneniia épiteliotsitov granuliarnykh vyvodnykh protokov i kontsevykh otdelov podnizhnecheliustnykh zhelez krys pri vozdeistvii sveta i radiatsii.

This investigation was aimed at the evaluation of radiomodifying effect of round-the-clock light exposure on the salivary glands. The changes of morphometric parameters of granular duct epitheliocytes and acinar cells in rat submandibular glands were analyzed by means of light and electron microscopy after 48 h of light exposure by 3500-lux cool white fluorescent lamps, single 5 Gy whole-body X-irradiation and their combination. Early changes of granular duct epitheliocytes after light and combined exposure were more significant in comparison with those on acinar cells. On the 10-th day after combined irradiation reduction of nucleoli and endoplasmatic reticulum in the duct cells was more pronounced as compared with similar period following light and X-ray irradiation. Long-term morphological changes in the glands after X-ray and combined irradiation were similar. It is concluded that radiation and round-the-clock light exposure act synergistically.

Extremely low frequency (ELF) pulsed-gradient magnetic fields inhibit malignant tumour growth at different biological levels.

Extremely low frequency (ELF) pulsed-gradient magnetic field (with the maximum intensity of 0.6-2.0 T, gradient of 10-100 T.M(-1), pulse width of 20-200 ms and frequency of 0.16-1.34 Hz treatment of mice can inhibit murine malignant tumour growth, as seen from analyses at different hierarchical levels, from organism, organ, to tissue, and down to cell and macromolecules. Such magnetic fields induce apoptosis of cancer cells, and arrest neoangiogenesis, preventing a supply developing to the tumour. The growth of sarcomas might be amenable to such new method of treatment.