Liquiritin ameliorates painful diabetic neuropathy in SD rats by inhibiting NLRP3-MMP-9-mediated reversal of aquaporin-4 polarity in the glymphatic system.

Background: Despite advancements in diabetes treatment, the management of Painful Diabetic Neuropathy (PDN) remains challenging. Our previous research indicated a significant correlation between the expression and distribution of Aquaporin-4 (AQP4) in the spinal glymphatic system and PDN. However, the potential role and mechanism of liquiritin in PDN treatment remain uncertain. Methods: This study established a rat model of PDN using a combination of low-dose Streptozotocin (STZ) and a high-fat, high-sugar diet. Rats were treated with liquiritin and MCC950 (an NLRP3 inhibitor). We monitored fasting blood glucose, body weight, and mechanical allodynia periodically. The glymphatic system's clearance function was evaluated using Magnetic Resonance Imaging (MRI), and changes in proteins including NLRP3, MMP-9, and AQP4 were detected through immunofluorescence and Western blot techniques. Results: The rats with painful diabetic neuropathy (PDN) demonstrated several physiological changes, including heightened mechanical allodynia, compromised clearance function within the spinal glymphatic system, altered distribution of AQP4, increased count of activated astrocytes, elevated expression levels of NLRP3 and MMP-9, and decreased expression of AQP4. However, following treatment with liquiritin and MCC950, these rats exhibited notable improvements. Conclusion: Liquiritin may promote the restoration of AQP4 polarity by inhibiting NLRP3 and MMP-9, thereby enhancing the clearance functions of the spinal cord glymphatic system in PDN rats, alleviating the progression of PDN.

Effect of adductor canal block combined with infiltration between the popliteal artery and posterior capsular of the knee on chronic pain after total knee arthroplasty: a prospective, randomized, double-blind, placebo-controlled trial.

INTRODUCTION: Total knee arthroplasty (TKA) is accompanied by severe postoperative pain, which is reported to be an important cause of chronic pain. Ultrasound-guided adductor canal block (ACB) combined with infiltration between the popliteal artery and posterior capsular of the knee (IPACK) has been proven to have a better effect on relieving acute pain after TKA. However, whether it has a significant effect on the incidence of chronic pain after TKA has not been reported. This trial was designed to investigate the effect of ultrasound-guided ACB combined with IPACK on the incidence and intensity of chronic pain after TKA. METHODS: In this prospective, randomized, double-blind, placebo-controlled study, 100 subjects scheduled for TKA were randomly (1:1) divided into two groups: the ropivacaine group and the placebo group. Patients in each group received ultrasound-guided ACB + IPACK procedures with 0.25% ropivacaine or equal volume normal saline. All patients received multimodal analgesia. Pain intensity was assessed using the Numerical Rating Scale (NRS). The primary outcome was the incidence of chronic pain at 3 months after TKA by telephone follow-up. In addition, pain intensity in early resting and mobilized states, chronic pain intensity, the time to first rescue analgesia; opioid consumption; CRP and IL-6 after the operation; length of postoperative hospital stay; and cost of hospitalization and postoperative complications; as well as the function of the knee in the early stage after the operation, were recorded. RESULTS: Ninety-one participants were included in the final analysis. At 3 months, the incidence of chronic pain was 30.4% in the ropivacaine group, significantly lower than 51.1% in the placebo group. Compared with the placebo group, the ACB + IPACK with ropivacaine group had significantly lower pain scores at 4 hours, 8 hours, 16 hours, and 24 hours after the operation; increased the knee range of motion at 8 hours and 24 hours after the operation; and a significantly decreased incidence of chronic pain at 3 months after the operation. During the follow-up period, there were no nerve block-related complications in either group. CONCLUSION: In the context of multimodal analgesia protocols, ACB combined with IPACK before surgery decreases the incidence and intensity of chronic pain 3 months after TKA compared with placebo injection. In addition, it reduces the NRS scores, whether at rest or during mobilization, and improves knee function within 24 hours after TKA. TRIAL REGISTRATION: This trial was registered in the China Clinical Trial Center (registration number ChiCTR2200065300) on November 1, 2022.

Effect of deep neuromuscular block on the quality of early recovery after sleeve gastrectomy in obese patients: a randomized controlled trial.

BACKGROUND: Deep neuromuscular block (NMB) has been shown to improve surgical conditions and alleviate post-operative pain in bariatric surgery compared with moderate NMB. We hypothesized that deep NMB could also improve the quality of early recovery after laparoscopic sleeve gastrectomy (LSG). METHODS: Eighty patients were randomized to receive either deep (post-tetanic count 1-3) or moderate (train-of-four count 1-3) NMB. The QoR-15 questionnaire was used to evaluate the quality of early recovery at 1 day before surgery (T0), 24 and 48 h after surgery (T2, T3). Additionally, we recorded diaphragm excursion (DE), postoperative pain, surgical condition, cumulative dose of analgesics, time of first flatus and ambulation, post-operative nausea and vomiting, time of tracheal tube removal and hospitalization time. MAIN RESULTS: The quality of recovery was significantly better 24 h after surgery in patients who received a deep versus moderate block (114.4 ± 12.9 versus 102.1 ± 18.1). Diaphragm excursion was significantly greater in the deep NMB group when patients performed maximal inspiration at T2 and T3 (P < 0.05). Patients who underwent deep NMB reported lower visceral pain scores 40 min after surgery; additionally, these patients experienced lower pain during movement at T3 (P < 0.05). Optimal surgical conditions were rated in 87.5% and 64.6% of all measurements during deep and moderate NMB respectively (P < 0.001). The time to tracheal tube removal was significantly longer in the deep NMB group (P = 0.001). There were no differences in other outcomes. CONCLUSION: In obese patients receiving deep NMB during LSG, we observed improved QoR-15 scores, greater diaphragmatic excursions, improved surgical conditions, and visceral pain scores were lower. More evidence is needed to determine the effects of deep NMB on these outcomes. TRIAL REGISTRATION: ChiCTR2200065919. Date of retrospectively registered: 18/11/2022.

Ginkgolide B can alleviate spinal cord glymphatic system dysfunction and provide neuroprotection in painful diabetic neuropathy rats by inhibiting matrix metalloproteinase-9.

The glymphatic system plays a crucial role in maintaining optimal central nervous system (CNS) function by facilitating the removal of metabolic wastes. Aquaporin-4 (AQP4) protein, predominantly located on astrocyte end-feet, is a key pathway for metabolic waste excretion. ß-Dystroglycan (ß-DG) can anchor AQP4 protein to the end-feet membrane of astrocytes and can be cleaved by matrix metalloproteinase (MMP)-9 protein. Studies have demonstrated that hyperglycemia upregulates MMP-9 expression in the nervous system, leading to neuropathic pain. Ginkgolide B (GB) exerts an inhibitory effect on the MMP-9 protein. In this study, we investigated whether inhibition of MMP-9-mediated ß-DG cleavage by GB is involved in the regulation of AQP4 polarity within the glymphatic system in painful diabetic neuropathy (PDN) and exerts neuroprotective effects. The PDN model was established by injecting streptozotocin (STZ). Functional changes in the glymphatic system were observed using magnetic resonance imaging (MRI). The paw withdrawal threshold (PWT) was measured to assess mechanical allodynia. The protein expressions of MMP-9, ß-DG, and AQP4 were detected by Western blotting and immunofluorescence. Our findings revealed significant decreases in the efficiency of contrast agent clearance within the spinal glymphatic system of the rats, accompanied by decreased PWT, increased MMP-9 protein expression, decreased ß-DG protein expression, and loss of AQP4 polarity. Notably, GB treatment demonstrated the capacity to ameliorate spinal cord glymphatic function by modulating AQP4 polarity through MMP-9 inhibition, offering a promising therapeutic avenue for PDN.

Aquaporins and Neuropathic Pain.

Neuropathic pain is a chronic secondary pain condition resulting from lesions or diseases of the peripheral or central nervous system (CNS). Neuropathic pain is closely related to edema, inflammation, increased neuronal excitability, and central sensitization caused by glutamate accumulation. Aquaporins (AQPs), mainly responsible for the transport and clearance of water and solute, play important roles in developing CNS diseases, especially neuropathic pain. This review focuses on the interaction of AQPs with neuropathic pain, and the potential of AQPs, especially aquaporins 4, as therapeutic targets.

Halorussus salinus sp. nov., isolated from a marine solar saltern.

A halophilic archaeal strain YJ-37-HT was isolated from Yangjiang marine solar saltern, China. Cells were pleomorphic rods, stained Gram negative and formed red-pigmented colonies on agar plate. Strain YJ-37-HT was able to grow at 20-50 °C (optimum 37 °C), at 0.9-4.8 M NaCl (optimum 2.6 M NaCl), at 0-1.0 M MgCl2 (optimum 0.3 MgCl2) and at pH 6.5-9.0 (optimum pH 7.0). The cells lysed in distilled water, and the minimal NaCl concentration to prevent cell lysis was found to be 5 % (w/v). The 16S rRNA gene and rpoB' gene of strain YJ-37-HT were phylogenetically related to the corresponding genes of Halorussus members (93.2-95.8 % and 90.1-93.9 % similarities, respectively). The major polar lipids of the strain were phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol sulfate (PGS) and five glycolipids, sulfated galactosyl mannosyl glucosyl diether (S-TGD-1), galactosyl mannosyl glucosyl diether (TGD-1), sulfated mannosyl glucosyl diether (S-DGD-1), mannosyl glucosyl diether (DGD-1) and diglycosyl diether (DGD-2). The DNA G+C content of strain YJ-37-HT was 64.9 mol%. The phenotypic, chemotaxonomic and phylogenetic properties suggested that strain YJ-37-HT (=CGMCC 1.12571T = JCM 30032T) represents a new species of Halorussus, for which the name Halorussus salinus sp. nov. is proposed.

Halomarina salina sp. nov., isolated from a marine solar saltern.

A halophilic archaeal strain, designated ZS-57-S(T), was isolated from Zhoushan marine solar saltern, China. Cells were observed to be pleomorphic, stained Gram-negative and formed red pigmented colonies on agar plates. Optimal growth was obtained at 3.9 M NaCl (range 1.4-4.8 M), 0.3 M MgCl2 (range 0-1.0 M), 30 °C (range 20-55 °C) and pH 6.5-7.5 (range 5.5-9.0). The cells were found to lyse in distilled water and the minimal NaCl concentration to prevent cell lysis was determined to be 5 % (w/v). The major polar lipids were identified as C20C20 and C20C25 diether derivatives of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate, glucosyl mannosyl glucosyl diether and two unidentified glycolipids. The 16S rRNA gene and rpoB' gene of strain ZS-57-S(T) were phylogenetically related to the corresponding genes of Halomarina oriensis JCM 16495(T) (98.2 and 93.7 % similarities, respectively). The DNA G+C content of strain ZS-57-S(T) was determined to be 67.1 mol% (T m). The phenotypic, chemotaxonomic and phylogenetic properties suggested that strain ZS-57-S(T) (=CGMCC 1.12543(T) = JCM 30039(T)) represents a new species of the genus Halomarina, for which the name Halomarina salina sp. nov. is proposed.

Salinigranum salinum sp. nov., isolated from a marine solar saltern.

An extremely halophilic archaeal strain YJ-50-S2T was isolated from Yangjiang marine solar saltern, China. Cells were pleomorphic, stained Gram-negative and formed red-pigmented colonies on agar plates. Strain YJ-50-S2T was able to grow at 25-50 °C (optimum 37 °C), with 0.9-4.8 M NaCl (optimum 2.6 M NaCl) and 0-1.0 M MgCl2 (optimum 0.03 M MgCl2), and at pH 5.0-9.5 (optimum pH 7.5). The cells lysed in distilled water and the minimal NaCl concentration to prevent cell lysis was 5 % (w/v). The 16S rRNA gene and rpoB' gene of strain YJ-50-S2T were phylogenetically related to the corresponding genes of Salinigranum rubrum GX10T (97.0 % and 90.5 % similarities, respectively). The major polar lipids of strainYJ-50-S2T were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, and two major glycolipids chromatographically identical to sulfated mannosyl glucosyl diether and mannosyl glucosyl diether, respectively. Several unidentified glycolipids were also detected. The DNA G+C content of strain YJ-50-S2T was 65.2 mol%. The phenotypic, chemotaxonomic and phylogenetic properties suggested that strain YJ-50-S2Trepresents a novel species of the genus Salinigranum, for which the name Salinigranum salinum sp. nov. is proposed. The type strain is YJ-50-S2T (=CGMCC 1.12572T=JCM 30033T).

Halorubrum rutilum sp. nov. isolated from a marine solar saltern.

A halophilic archaeal strain, YJ-18-S1(T), was isolated from Yangjiang marine solar saltern, Guangxi Province, China. Cells were pleomorphic, stained Gram-negative and formed red-pigmented colonies on agar plates. Strain YJ-18-S1(T) was able to grow at 20-55 °C (optimum 37 °C), at 0.9-4.8 M NaCl (optimum 2.6 M NaCl), at 0.005-1.0 M MgCl2 (optimum 0.3 MgCl2) and at pH 5.5-8.5 (optimum pH 7.0). The cells were lysed in distilled water, and the minimal NaCl concentration to prevent cell lysis was found to be 5 % (w/v). The major polar lipids of the strain were phosphatidic acid, phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and sulfated mannosyl glucosyl diether. The 16S rRNA gene and rpoB' gene of strain YJ-18-S1(T) were phylogenetically related to the corresponding genes of Halorubrum members (94.3-98.0 and 86.7-96.1 % similarities, respectively). The DNA G+C content of strain YJ-18-S1(T) was 66.2 mol%. The phenotypic, chemotaxonomic and phylogenetic properties suggested that strain YJ-18-S1(T) (=CGMCC 1.12554(T) = JCM 30030(T)) represents a new species of Halorubrum, for which the name Halorubrum rutilum sp. nov. is proposed.

Halosimplex litoreum sp. nov., isolated from a marine solar saltern.

A halophilic archaeal strain, YGH94(T), was isolated from the Yinggehai marine solar saltern near the Shanya city of Hainan Province, China. Cells of the strain were observed to be short rods, stain Gram-negative and to form red-pigmented colonies on solid media. Strain YGH94(T) was found to grow at 25-50 °C (optimum 40 °C), at 0.9-4.8 M NaCl (optimum 3.1 M), at 0-1.0 M MgCl2 (optimum 0.05 M) and at pH 5.0-9.0 (optimum pH 7.5). The cells were found to lyse in distilled water and the minimal NaCl concentration to prevent cell-lysis was determined to be 5 % (w/v). The major polar lipids were identified as phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and four major glycolipids (disulfated mannosyl glucosyl diether, sulfated mannosyl glucosyl diether and two unidentified glycolipids chromatographically identical to glycolipids in Halosimplex carlsbadense JCM 11222(T)). Strain YGH94(T) was found to possess two heterogeneous 16S rRNA genes (rrnA and rrnB) and both are related to those of Hsx. carlsbadense JCM 11222(T) (92.7-98.6 % similarities), Halosimplex pelagicum R2(T) (94.6-99.2 % similarities) and Halosimplex rubrum R27(T) (92.9-98.8 % similarities). The rpoB' gene similarity between strain YGH94(T) and Hsx. carlsbadense JCM 11222(T), Hsx. pelagicum R2(T) and Hsx. rubrum R27(T) are 95.4, 94.9 and 95.1 %, respectively. The DNA G+C content of strain YGH94(T) was determined to be 64.0 mol%. Strain YGH94(T) showed low DNA-DNA relatedness (35-39 %) with the current three members of the genus Halosimplex. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strain YGH94(T) (=CGMCC 1.12235(T) = JCM 18647(T)) represents a new species of the genus Halosimplex, for which the name Halosimplex litoreum sp. nov. is proposed.