[Inhibition connexin 43 by mimetic peptide Gap27 mediates protective effects on 6-hydroxydopamine induced Parkinson's disease mouse model]

OBJECTIVE

To explore whether the using of mimetic peptide Gap27, a selective inhibitor of connexin 43 (Cx43), could block the death of dopamine neurons and influence the expression of Cx43 in 6-hydroxydopamine (6-OHDA)-induced Parkinson's disease mouse models.

METHODS

Eighteen C57BL/6 mice were randomly divided into control group, 6-OHDA group and 6-OHDA+Gap27 group, with 6 mice in each group. Bilateral substantia nigra stereotactic injection was performed. The control group was injected with ascorbate solution, 6-OHDA group was injected with 6-OHDA solution, and 6-OHDA+Gap27 group was injected with 6-OHDA and Gap27 mixed solution. Immuno-histochemical staining was used to detect the number of dopamine neurons, quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of Cx43 messenger ribonucleic acid (mRNA), immuno-fluorescence staining was used to detect the distribution of Cx43 protein, the contents of Cx43 protein and Cx43 phosphorylation at serine 368 (Cx43-ps368) in mouse midbrain were detected by Western blot.

RESULTS

After injection of 6-OHDA, numerous dopamine neurons in substantia nigra died as Cx43 content increased, Cx43-ps368 content decreased. Mixing Gap27 while injecting 6-OHDA could reduce the number of death dopamine neurons and weaken the changes of Cx43 and Cx43-ps368 content caused by 6-OHDA. The number of tyrosine hydroxylase (TH) immunoreactive positive neurons in 6-OHDA group decreased to 27.7% ± 0.02% of the control group (P < 0.01); The number of TH immunoreactive positive neurons in 6-OHDA+Gap27 group was (1.64±0.16) times higher than that in 6-OHDA group (P < 0.05); The content of total Cx43 protein in 6-OHDA group was (1.44±0.07) times higher than that in 6-OHDA+Gap27 group (P < 0.05) while (1.68±0.07) times higher than that in control group (P < 0.01). In 6-OHDA group, the content of Cx43-ps368 protein and its proportion in total Cx43 protein were significantly lower than that in 6-OHDA+Gap27 group (P < 0.05).

CONCLUSION

In 6-OHDA mouse models, mimetic peptide Gap27 played a protective role in reducing the damage to substantia nigra dopamine neurons, which was induced by 6-OHDA. The overexpression of Cx43 protein might have neurotoxicity to dopamine neuron. Meanwhile, decreasing Cx43 protein level and keeping Cx43-ps368 protein level may be the protective mechanisms of Gap27.

Risk factors for serious infections in inpatients with systemic lupus erythematosus

OBJECTIVES

To investigate the risk factors for serious infections among hospitalized systemic lupus erythematosus (SLE) patients, and to provide the advice for preventing serious infections in SLE patients.

METHODS

Information of SLE patients hospitalized from March 2017 to February 2019 at the Department of Rheumatology and Immunology, Xiangya Hospital, Central South University was obtained. The patients were assigned into a serious infection group and a non-serious infection group. The risk factors for serious infections among SLE inpatients were identified by comparison between the 2 groups and multivariate logistic regression analysis.

RESULTS

There were 463 SLE inpatients in total, and 144 were in the serious infection group and 319 in the non-serious infection group. Multivariate logistic regression analysis showed that age ≥54.50 years old (OR=4.958, P<0.001), cardiovascular involvement (OR=6.287, P<0.001), hematologic involvement (OR=2.643, P=0.003), serum albumin <20 g/L (OR=2.340, P=0.036), C-reaction protein (CRP)/erythrocyte sedimentation rate (ESR)≥0.12 (OR=2.430, P=0.002), glucocorticoid dose ≥8.75 mg/d prednisone-equivalent (OR=2.465, P=0.002), and the combined use of immunosuppressive agents (OR=2.847, P=0.037) were the risk factors for serious infections in SLE inpatients.

CONCLUSIONS

SLE patients with older age, cardiovascular involvement, hematologic involvement, low serum albumin are prone to suffering serious infections. Increased CRP/ESR ratio indicates serious infections in SLE inpatients. High-dose glucocorticoid and the combined use of immunosuppressive agents can increase the risk of serious infections in SLE inpatients.