Improved Cuff Technique for Establishing a Mouse-Rat Heterotopic Cardiac Xenotransplantation Model

Xylazine Regulates the Release of Glycine and Aspartic Acid in Rat Brain

Introduction

Xylazine, a type of α₂-adrenoceptors, is a commonly used drug in veterinary medicine. Xylazine-induced changes in the content of amino acid neurotransmitters - glycine (Gly) and aspartic acid (Asp), in different brain regions and neurons were studied.

Material and Methods

Wistar rats were administered 50 mg/kg or 70 mg/kg of xylazine by intraperitoneal injection. In addition, in vitro experiments were conducted, in which neurons were treated with 15 μg/mL, 25 μg/mL, 35μg/mL, and 45 μg/mL of xylazine. Test methods were based on the enzyme-linked immunosorbent assays (ELISA).

Results

During anaesthesia, Asp levels in each brain area were significantly lower compared to the control group. Except for the cerebrum, levels of Gly in other brain areas were significantly increased during the anaesthesia period. In vitro, xylazine-related neuron secretion of Gly increased significantly compared to the control group at 60 min and 90 min. Moreover, xylazine caused a significant decrease in the levels of Asp secreted by neurons at 20 min, but gradually returned to the level of the control group.

Conclusion

The data showed that during anaesthesia the overall levels of Asp decreased and overall levels of Gly increased. In addition, the inhibitory effect of xylazine on Asp and the promotion of Gly were dose-dependent. Our data showed that different effects of xylazine on excitatory and inhibitory neurotransmitters provided a theoretical basis for the mechanism of xylazine activity in clinical anaesthesia.

Xylazine regulates the release of glycine and aspartic acid in rat brain

Introduction

Xylazine, a type of α2-adrenoceptors, is a commonly used drug in veterinary medicine. Xylazine-induced changes in the content of amino acid neurotransmitters – glycine (Gly) and aspartic acid (Asp), in different brain regions and neurons were studied.

Material and Methods

Wistar rats were administered 50 mg/kg or 70 mg/kg of xylazine by intraperitoneal injection. In addition, in vitro experiments were conducted, in which neurons were treated with 15 μg/mL, 25 μg/mL, 35μg/mL, and 45 μg/mL of xylazine. Test methods were based on the enzyme-linked immunosorbent assays (ELISA).

Results

During anaesthesia, Asp levels in each brain area were significantly lower compared to the control group. Except for the cerebrum, levels of Gly in other brain areas were significantly increased during the anaesthesia period. In vitro, xylazine-related neuron secretion of Gly increased significantly compared to the control group at 60 min and 90 min. Moreover, xylazine caused a significant decrease in the levels of Asp secreted by neurons at 20 min, but gradually returned to the level of the control group.

Conclusion

The data showed that during anaesthesia the overall levels of Asp decreased and overall levels of Gly increased. In addition, the inhibitory effect of xylazine on Asp and the promotion of Gly were dose-dependent. Our data showed that different effects of xylazine on excitatory and inhibitory neurotransmitters provided a theoretical basis for the mechanism of xylazine activity in clinical anaesthesia.

Acute Rejection Pattern of an Outbred Strain Combination on Mouse-to-Rat Heterotopic Heart Xenotransplantation

OBJECTIVES

This study aimed to investigate the acute rejection patterns of outbred mice and rats on a xenotransplantation model.

MATERIALS AND METHODS

Thirty male Balb/c mice weighing from 30 to 40 g were used as donors, and 30 male outbred Sprague-Dawley rats weighing from 150 to 200 g were used as recipients for heterotopic heart xenotransplantation models. Animals were allocated into 5 groups according to their killed days, and each group had 6 animals. Animals in group 1 were followed for 1 day and then killed; animals in groups 2, 3, 4, and 5 were followed up 2, 3, 4, and 5 days after transplantation, respectively. Operative findings, the appearance and heartbeat strength of the grafts, and histopathologic examinations of the grafts were evaluated to determine acute rejection.

RESULTS

There were no mortalities during the study period, and the animal survival rate was 100%. Heartbeat strengths were strong (4.5 ± 0.5) and graft appearances were normal in group 1 animals. The heartbeat scores of the xenografts dramatically declined thereafter. Histopathologically, there were inflammation patterns in all xenografts. The infiltration of neutrophils and the formation of platelet and fibrin thrombi were seen in the first postoperative day and gradually increased daily.

CONCLUSIONS

This study concluded that outbred Balb/c mouse to Sprague-Dawley rat combination has reliable acute xenograft rejection patterns microscopically and macroscopically in the heterotopic heart xenotransplantation model.

A New Concept of the Old Inhibitor NSC 74859 in Alleviating Cardiac Allograft Rejection and Extending Allograft Survival in Mice

Background

STAT1/4 has been suggested to be involved in cardiac allograft rejection. However, no direct evidence regarding STAT3 has been established in cardiac allograft rejection. Here, we hypothesized that inhibition of STAT3 attenuates cardiac allograft rejection.

Material/Methods

To test our hypothesis, homotopic mouse heart transplantation was carried out in syngeneic C57BL/6 to C57BL/6 strain mice with or without oral gavage with NSC 74859, an inhibitor of STAT3. The immune response was investigated using real-time PCR for CD4 and CD8 surface makers of T cells and CD14 of monocytes and cytokines, including IL-2, IL-15, and IL-6 of allografts at 3, 6, and 9 days after transplantation. Prognosis was also evaluated.

Results

We found that allografts with oral gavage of NSC 74859 whose CD4, CD8 T, and CD14 monocytes were significantly lower than that of allograft without oral gavage of NSC 74859, and the same was true for the expression of IL-2, IL-15, and IL-6. Immunohistochemical analysis of grafts showed reduced infiltration of monocytes/macrophages into the graft myocardium. Survival was also markedly extended in the NSC 74859 group.

Conclusions

Inhibition of IL-6/STAT3 using NSC 74859 was shown to remarkably alleviate cardiac allograft rejection in mice, indicating that the target against IL-6/STAT3 pathway might be clinically used as an alternative therapy for cardiac allograft rejection.