Inhibition of aberrant cyclin-dependent kinase 5 activity attenuates isoflurane neurotoxicity in the developing brain

Aberrant CDK5 activity is implicated in a number of neurodegenerative disorders. Isoflurane exposure leads to neuronal apoptosis, and subsequent learning and memory defects in the developing brain. The present study was designed to examine whether and how CDK5 activity plays a role in developmental isoflurane neurotoxicity. Rat pups and hippocampal neuronal cultures were exposed to 1.5% isoflurane for 4 h. The protein and mRNA levels of CDK5, p35 and p25 were detected by western blot and QReal-Time PCR. CDK5 activity was evaluated in vitro using Histone H1 as a substrate. Roscovitine (an inhibitor of CDK5) was applied before isoflurane treatment, cleaved Caspase-3, Bcl-2, Bax, MEF2 and phospho-MEF2A-Ser-408 expressions were determined. Dominant-Negative CDK5 was transfected before isoflurane treatment. Neuronal apoptosis was evaluated by Flow cytometry (FCM) and TUNEL-staining. Cognitive functions were assessed by Morris water maze. We found that isoflurane treatment led to an aberrant CDK5 activation due to its activator p25 that was cleaved from p35 by calpain. Inhibition of CDK5 activity with Roscovitine enhanced Bcl-2, and decreased cleaved Caspase-3 and Bax expressions. In addition, isoflurane exposure resulted in a decrease of MEF2 and increase of phospho-MEF2A-Ser-408, which were rescued by Roscovitine or Dominant-Negative CDK5 transfection. Dominant-Negative CDK5 transfection also decreased the percentage of TUNEL-positive cells in isoflurane neurotoxicity. Moreover, Roscovitine remarkably alleviated the learning and memory deficits induced by postnatal isoflurane exposure. These results indicated that aberrant CDK5 activity-dependent MEF2 phosphorylation mediates developmental isoflurane neurotoxicity. Inhibition of CDK5 overactivation contributes to the relief of isoflurane neurotoxicity in the developing brain.

Discovery and characteristics of B cell-like T cells: A potential novel tumor immune marker?

BACKGROUND

CD3 and CD19 are the characteristic surface markers of mature T lymphocytes and B lymphocytes of human respectively. A special subset of immune cells that characteristically expressed the surface markers CD19+ of B lymphocytes and CD3+ of T lymphocytes simultaneously (CD19+CD3+ cells, hereinafter referred to as B-T cells) was found in the peripheral blood of human, yet it has not been reported in cancer research before. Our aims were to characterize the expression and possible value of B-T cells in cancer patients.

METHODS

Flow cytometry was applied to analyse the CD19+CD3+ cells, and laser scanning confocal microscope was utilized to prove co-expressing CD19+ of B lymphocytes and CD3+ of T lymphocytes simultaneously on the surface of the cells. Then a total of 523 patients with malignant tumor were enrolled in this study, and 177 healthy donors were recruited as the control group. The levels of CD19+CD3+ cells in peripheral blood were measured by flow cytometry, and the differences between the two groups were compared.

RESULTS

The healthy donors and cancer patients all had B-T cells in their peripheral blood, but the percentage of B-T cells was 0.16 % ± 0.11 % and 0.58 % ± 0.38 % respectively, showing statistically significant (P < 0.0001). There was no significant correlation between the percentage of B-T cells and lymphocyte subsets (P > 0.05). The percentages of B-T cells in different tumor species were different. The proportion of B-T cells was high in esophageal cancer, non-Hodgkin's lymphoma and lung cancer, but it was low in pancreatic cancer, ovarian cancer and kidney cancer. Meanwhile, there was significant difference between esophageal cancer and kidney cancer (P < 0.001). The distribution of B-T cells in pancreatic cancer and kidney cancer was more concentrated, yet more dispersed in other cancers. Although there was a trend of increase in clinical stage Ⅲ+Ⅳ and a trend of decrease in age above 60 years for breast cancer, gastric cancer and liver cancer, there was no significant difference in the percentage of B-T cells in age, gender, different clinical stages, tumor metastasis, lymph node metastasis, and splenomegaly (P > 0.05).

CONCLUSION

The percentage of B-T cells in cancer patients was significantly higher than that of healthy donors. B-T cells maybe play a very complicated role in tumor, whether it could be a potential tumor immune marker or not and what are the specific phenotypes and functions of it to need be further verified.

The Effects of Different Fluorescent Indicators in Observing the Changes of the Mitochondrial Membrane Potential during Oxidative Stress-Induced Mitochondrial Injury of Cardiac H9c2 Cells

We evaluated the ability of different fluorescent indicators by various analytical instruments, including a laser scanning confocal microscope (LSCM), fluorescence plate reader, and flow cytometer (FCM), to measure the mitochondrial membrane potential (ΔΨm) of cardiac H9c2 cells during oxidative stress-induced mitochondrial injury. The mitochondrial oxygen consumption rate and a transmission electron microscope were used to detect changes in mitochondrial functions and morphology, respectively. Cardiac H9c2 cells were exposed to H₂O₂ (500, 750, 1000, and 1250 μM) to induce mitochondrial oxidative stress injury, and fluorescent indicators including tetramethyl rhodamine ethyl ester (TMRE), 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine iodide (JC-1), and rhodamine 123 (R123) were used to detect changes in ΔΨm using an LSCM, fluorescence plate reader, and FCM. The decrease in ΔΨm caused by H₂O₂ was determined by endpoint and dynamic analyses after staining with JC-1 or TMRE. With the R123 probe, the LSCM could only detect the change in ΔΨm caused by 1000 μM H₂O₂. Moreover, R123 was less effective than JC-1 and TMRE for measurement of ΔΨm by the LSCM. Our data indicated that an LSCM is the most suitable instrument to detect dynamic changes in ΔΨm, whereas all three instruments can detect ΔΨm at the endpoint.

Three-dimensional visualization of coronary microvasculature in rats with myocardial infarction

BACKGROUND

Assessment of the coronary microcirculation remains challenging.

OBJECTIVE

we explored the feasibility of evaluating the coronary microvasculature in rats with myocardial infarction (MI) using a three-dimensional visualization technique.

METHODS

Animals were divided into the sham operation group (S), MI 45 min group (M45), and MI 180 min group (M180). Opened microvessels were labelled with the fluorescent dye DiI (1, 1'-dioctadecyl-3, 3, 3'3'-tetramethylindo carbocyanine perchlorate) using a heart perfusion method. The microvascular distribution and opening status were observed under laser scanning confocal microscopy, which was adjusted to facilitate evaluation of subjects around 6 to 20 μm.

RESULTS

Microvascular vessels (6-20 μm) were successfully labelled by DiI. Intact and clear three-dimensional microvascular structures were observed in myocardium of sham rats and remote non-infarct myocardial tissue of MI rats, while there was almost no microvascular structure in the infarct area of the M45 group, and only a small amount of microvascular visualization was visualized in the infarct area of the M180 group. The microvascular area and microvascular density in M45 group and M180 group in the infarct border zone were significantly lower than corresponding area in S group.

CONCLUSION

Three-dimensional visualization of opened coronary microvascular vessels is feasible in DiI-labelled myocardium in this rat MI model. This novel technique might be useful for defining the underlying mechanisms of coronary microvascular diseases and observe the efficacy of various therapy strategies on coronary microvessels.

In situ analysis of volatile oil in Angelica sinensis roots by fluorescence imaging combined with mass spectrometry imaging

In this study, the spatial distribution and accumulation dynamics of volatile oil in Angelica sinensis roots was realized by fluorescence imaging combined with mass spectrometry imaging. The laser scanning confocal microscopy was used to determine the optimal excitation wavelength and the fluorescent stability of volatile oil in the sections of Angelica sinensis roots. The results demonstrated that 488 nm was the most suitable excitation wavelength for the identification and quantitative analysis of volatile oil. It was observed that volatile oil accumulated in the oil chamber of the phelloderm and secondary phloem, and the oil canal of the secondary xylem. The results also indicated that there were differences in content during different periods. Furthermore, the MALDI-TOF-MSI technology was used to study the spatial distribution and compare the chemical compositions of different parts of Angelica sinensis roots during the harvest period. A total of 55, 49, 50 and 30 compounds were identified from the head, body, tail of the root and root bark, respectively. The spatial distribution of phthalides, organic acids and other compounds were revealed in Angelica sinensis roots. The method developed in this study could be used for the in situ analysis of volatile oil in Angelica sinensis roots.

Effects of Arecolinehydrobromide on contraction and intracellular free Ca2+ concentrations of colonic smooth muscle cells

AIM: To explore the possible role of Arecolinehy-drobromide (Ah) in the dynamics of digestive tract and the effects of Ah on the contraction of colon smooth muscle cells (SMCs) and the con-centration of intracellular [Ca²⁺]i.

METHODS: SMCs from colon of mice were cultured in vitro. Based on different treatment methods, four groups were divided into as follows: Ah group in which cultured SMCs were stimulated by Ah; control group in which there was no additional treatment on cultured SMCs; Acetylcholine (Ach) group in which cultured SMCs were stimulated by Ach; Atropine group in which cultured SMCs were pretreated with atropine before Ah was added. Laser scanning confocal microscope (LSCM) was used to measure the concentration of intracellular [Ca²⁺]i and the contraction of colon SMCs in the above four groups.

RESULTS: No spontaneous cellular contraction took place in control group in which there was a tendency of decrease in fluorescent intensity because of attenuation of the indicator. In Ah group, a rapid elevation in the concentration of intracellular [Ca^2+]i occurred shortly after Ah was added, which was recorded as a pulse wave. Then there was a gradual and slow increase in intracellular [Ca²⁺]i which reached its peak at 484.0 ± 47.6 s. The peak was followed by a quite long plateau and afterward returned to the resting level at 1 400 s. The percentage of cellular contraction was 20.70% ± 0.07%. In Ah and Ach groups, a tendency of SMCs contraction in accordance with elevation of intracellular [Ca²⁺]i was observed following Ah or Ach was added. However, the effect was faster and shorter in Ah group than that in Ach group. The contractive effect of Ah was completely inhibited in SMCs pretreated by atropine.

CONCLUSION: Ah can cause contraction of SMCs of colon and increase of intracellular [Ca²⁺]i. The contractive effect of Ah can be effectively inhibited by atropine. Ah may be promising for improving dynamics of digestive tract.

[Application of Laser Scanning Confocal Microscope to Morphologic Research of Acupuncture and Moxibustion]

Laser scanning confocal microscope (LSCM) has been used in the field of morphological research of acupuncture and moxibustion for more than 20 years. It is one of the important tools for revealing the structure of acupoints and the effect of acupuncture from histological perspective. With the help of technical advantages of LSCM, the quality of morphological research of acupuncture and moxibustion has been greatly improved, helping us gain a deeper understanding about the structure of acupoints and meridians as well as histochemical changes induced by acupuncture/moxibustion intervention. In order to promote the application of LSCM in acupuncture and moxibustion, we simply reviewed some recent studies in this field and combined them with our experience, trying to provide some technical suggestions. We expect that the technique of LSCM could be integrated into more experiments in acupuncture medicine to provide more powerful morphological evidence for exploring the underlying mechanisms of acupuncture and moxibution therapies.