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Objective:To investigate the relationship between intracellular calcium level and neutrophil migration dysfunction in patients with sepsis.Methods:This study retrospectively collected 21 blood samples of patients with sepsis in the First Hospital of Jilin University from December 2017 to September 2018, and 20 healthy people were included as the control group. Peripheral blood neutrophils were isolated from the healthy controls and patients with sepsis using magnetic-activated cell sorting. Multichannel microfluidic microarray technology was used to detect the chemotactic migration of neutrophils. The levels of calcium in neutrophils from healthy controls and sepsis patients as well as in neutrophils from healthy controls that were pretreated with calcium chelators BAPTA-AM and EDTA were detected by flow cytometry using the calcium indicator Fluo-4.Results:The intracellular calcium levels were lower in neutrophils from sepsis patients than in those from healthy controls ( P<0.01). BAPTA-AM and EDTA could reduce the calcium level in neutrophils of healthy controls ( P<0.01). Microfluidics revealed that the migration speed, distance and gap-passing rate of neutrophils in microfluidics were significantly reduced after the decrease of intracellular calcium ( P<0.01). Conclusions:Reduced calcium levels in neutrophils of patients with sepsis may be closely related to the decreased cell migration. This study suggests that the migration impairment of neutrophils can be improved by regulating intracellular calcium levels, which provides a new idea for further research.
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OBJECTIVE: To observe the changes of intracellular calcium ([Ca2＋]i) concentration and expression of calcium/calmodulin dependent protein kinaseⅡ (CaMKⅡ) in spinal dorsal horn neurons of spared nerve injury (SNI) rats, so as to explore its mechanisms underlying improvement of neuropathic pain. METHODS: One hundred and ten SD rats were randomly divided into 5 groups: sham control, model, EA, AP-5 and L-NAME groups. The sham group underwent only a simple separation of the sciatic nerve but without ligation and abscission. The neuropathic pain model was established by abscission of the right tibial and common peroneal nerve. EA (2 Hz, 1－3 mA) was applied to right "Weizhong" (BL 40) and "Huantiao" (GB 30) for 30 min, once a day for 7 days, starting from day 11 after surgery. For rats of the AP-5 and L-NAME groups, AP-5 (a competitive antagonist for NMDA receptor, 0.7 mg·kg－1·d－1) and L-NAME (a non-selective antagonist for nitric oxide synthase [NOS], 60 mg·kg－1·d－1) were respectively administrated by intraperitoneal injection, once daily for 7 days. The mechanical pain threshold was measured, and the calcium fluorescence intensity (shown by Fluo-3/AM calcium fluorescence indicator) of the superficial layer of the lumbar spinal cord (L 4－L 6) was measured by immunohistochemical staining and the expression of spinal cord (L 4－L 6) CaMK Ⅱ protein was detected by Western blot (WB). RESULTS: After modeling, the mechanical pain threshold was significantly decreased on day 10 and 16 after operation in comparison with the sham operation group and baseline data of pre-operation in each group (P<0.01), and remarkably increased in the EA, AP-5 and L-NAME groups relevant to the model group on day 16 (P<0.01, P<0.05), while the effect of EA was significantly superior to that of AP-5 and L-NAME groups (P<0.05), suggesting a reduction of EA analgesia after administration of AP-5 and L-NAME. The concentration of intracellular [Ca2＋]i was significantly higher in the model group than in the sham group, and considerably lower in the EA, AP-5 and L-NAME groups than in the model group (P<0.01, P<0.05). Moreover, the expression level of CaMKⅡ shown by WB and immunohistochemical staining was significantly higher in the model group than in the sham group (P<0.05) and obviously lower in the EA group (not the AP-5 and L-NAME groups) than in the model group on day 16 after the intervention (P<0.05). It suggests an involvement of glutamate NMDA receptor and NMDAR-NOS/NO signaling in the analgesic effect and CaMKⅡ expression down-regulation of EA. CONCLUSIONS: EA can ease pain in rats with neuropathic pain, which is closely related to its effect in reducing the calcium concentration and the expression of CaMKⅡ in the lumbar spinal cord, possibly mediated by glutamate NMDA receptor and NMDAR-NOS/NO signaling.