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.

A retrospective study on the relationship between 5 modified frailty index (5-mFI) and postoperative complications of gynecological elderly patients undergoing abdominal surgery.

INTRODUCTION: Aim to evaluate the application of 5 modified frailty index (5-mFI) in predicting postoperative complications in elderly gynecological patients undergoing abdominal surgery. METHODS: A total of 294 elderly gynecological patients who were hospitalized in the affiliated Hospital of North Sichuan Medical College and underwent abdominal surgery from November 2019 to May 2022 were collected from the Union Digital Medical Record (UniDMR) Browser of the hospital. According to whether postoperative complications (infection, hypokalemia, hypoproteinemia, poor wound healing and intestinal obstruction) occurred, the patients were divided into complication group (n = 98) and non-complication group (n = 196). Univariate and multivariate logistic regression analysis were used to analyze the risk factors of complications in elderly gynecological patients undergoing abdominal surgery. The receiver operating characteristic (ROC) curve was used to determine the predictive value of the frailty index score in elderly gynecological patients with postoperative complications after abdominal surgery. RESULTS: Postoperative complications occurred in 98 of 294 elderly gynecological patients undergoing abdominal surgery, accounting for 33.3%, 5-mFI (OR1.63, 95%CI 1.07-2.46,P = 0.022), age (OR1.08,95%CI 1.02-1.15, P = 0.009), operation time (OR 1.01, 95%CI 1.00-1.01). P < 0.001) were independent risk factors for postoperative complications in elderly patients undergoing abdominal surgery, and the area under the curve of postoperative complications in elderly gynecological patients was 0.60. (95%CI: 0.53-0.67, P = 0.005) CONCLUSION: Five modified frailty index can effectively predict the occurrence of postoperative complications in elderly gynecological patients.

Plasticity of the spinal glymphatic system in male SD rats with painful diabetic neuropathy induced by type 2 diabetes mellitus.

The glymphatic system is a recently discovered glial-dependent macroscopic interstitial waste clearance system that promotes the efficient elimination of soluble proteins and metabolites from the central nervous system. Its anatomic foundation is the astrocytes and aquaporin-4 (AQP4) water channels on the endfeet of astrocytes. The aim of this study is to evaluate the plasticity of the spinal glymphatic system in male SD rats with painful diabetic neuropathy (PDN) induced by type 2 diabetes mellitus. PDN rats were modeled under a high-fat and high-glucose diet with a low dose of streptozotocin. MRI was applied to observe the infiltration and clearance of contrast to indicate the functional variability of the glymphatic system at the spinal cord level. The paw withdrawal threshold was used to represent mechanical allodynia. The numerical change of glial fibrillary acidic protein (GFAP) positive astrocytes was assessed and the polarity reversal of AQP4 protein was measured by immunofluorescence. As a result, deceased contrast infiltration and clearance, enhanced mechanical allodynia, increased number of GFAP positive astrocytes, and reversed polarity of AQP4 protein were found in the PDN rats. The above molecular level changes may contribute to the impairment of the spinal glymphatic system in PDN rats. This study revealed the molecular and functional variations of the spinal glymphatic system in PDN rats and for the first time indicated that there might be a correlation between the impaired spinal glymphatic system and PDN rats.

Effects of dynamic individualized PEEP guided by driving pressure in laparoscopic surgery on postoperative atelectasis in elderly patients: a prospective randomized controlled trial.

BACKGROUND: Driving pressure (ΔP = Plateau pressure-PEEP) is highly correlated with postoperative pulmonary complications (PPCs) and appears to be a promising indicator for optimizing ventilator settings. We hypothesized that dynamic, individualized positive end-expiratory pressure (PEEP) guided by ΔP could reduce postoperative atelectasis and improve intraoperative oxygenation, respiratory mechanics, and reduce the incidence of PPCs on elderly patients undergoing laparoscopic surgery. METHODS: Fifty-one elderly patients who were subject to laparoscopic surgery participated in this randomized trial. In the PEEP titration group (DV group), the PEEP titration was decremented to the lowest ΔP and repeated every 1 h. Additional procedures were also performed when performing predefined events that may be associated with lung collapse. In the constant PEEP group (PV group), a PEEP of 6 cmH2O was used throughout the surgery. Moreover, zero PEEP was applied during the entire procedure in the conventional ventilation group (CV group). The primary objective of this study was lung ultrasound score noted at the end of surgery and 15 min after admission to the post-anesthesia care unit (PACU) at 12 lung areas bilaterally. The secondary endpoints were perioperative oxygenation function, expiratory mechanics, and the incidence of the PPCs. RESULTS: The lung ultrasound scores of the DV group were significantly lower than those in the PV group and CV group (P < 0.05), whereas there was no significant difference between the PV group and CV group (P > 0.05). The lung static compliance (Cstat) and ΔP at all the intraoperative time points in the DV group were significantly better compared to the PV group and the CV group (p < 0.05). CONCLUSIONS: Intraoperative titrated PEEP reduced postoperative lung atelectasis and improved respiratory mechanics in elderly patients undergoing laparoscopic surgery. Meanwhile, standard PEEP strategy is not superior to conventional ventilation in reducing postoperative pulmonary atelectasis in laparoscopic surgery.

Effect of low-concentration carbohydrate on patient-centered quality of recovery in patients undergoing thyroidectomy: a prospective randomized trial.

BACKROUND: At present, low-concentration carbohydrate is rarely used in minor trauma surgery, and its clinical efficacy is unknown. The aim of the study was to evaluate the effect of preoperative oral low-concentration carbohydrate on patient-centered quality of recovery in patients undergoing thyroidectomy using Quality of Recovery - 15 (QoR-15) questionnaire. METHODS: One hundred twenty patients were randomized to oral intake of 300 ml carbohydrate solution (CH group) or 300 ml pure water (PW group) 2 h before surgery or fasting for 8 h before surgery (F group). The QoR-15 questionnaire was administered to compare the quality of recovery at 1d before surgery (T0), 24 h, 48 h, 72 h after surgery (T1, T2, T3), and perioperative blood glucose was recorded. RESULTS: Compared to the F group, the QoR-15 scores were statistically higher in the CH and PW group at T1 (P < 0.05), and the enhancement of recovery quality reached the clinical significance at T1 in the CH group compared with the F group. Among the five dimensions of the QoR-15 questionnaire, physical comfort, physiological support and emotional dimension in the CH group were significantly better than the F group (P < 0.05) at T1. Besides, blood glucose of CH group was significantly lower than the PW group and F group at each time point after surgery. CONCLUSIONS: Low-concentration carbohydrate could decrease the incidence of postoperative hyperglycemia and improve the patient-centered quality of recovery on patients undergoing open thyroidectomy at the early stage postoperatively. TRIAL REGISTRATION: ChiCTR1900024731 . Date of registration: 25/07/2019.

Simulation-based training following a theoretical lecture enhances the performance of medical students in the interpretation and short-term retention of 20 cross-sectional transesophageal echocardiographic views: a prospective, randomized, controlled trial.

BACKGROUND: Both simulation-based training and video-based training serve as educational adjuncts for learning TEE among medical students. In the present study, we hypothesized that simulation-based training would better enhance the performance of medical students in the interpretation of 20 cross-sectional views compared to video-based training. METHODS: A total of 120 4th-year undergraduate medical students were enrolled in the present study. The study began with a pre-test of all the participants, followed by a 90-min theoretical lecture and a post-test. Subsequently, the participants were randomly divided into the video-based group (Group V) and simulation-based group (Group S). Next, Group V received 60 min of TEE video learning, while Group S received 60 min of TEE simulator training. After the respective training, both the groups undertook the retention-test 1 and retention-test 2, 1 week and 1 month later, respectively. The performance for each test was evaluated by five views, which were selected randomly and, respectively, from a set of 20 cross-sectional views. The primary outcome was the performance of the retention-test 1. Secondary outcomes included: (1) comparison the performances of the pre-test, post-test, and retention-test 2 between two groups; (2) comparison the performances of pre-test and post-test in the same group; (3) comparison the performances of retention-test 1, and retention-test 2 in the same group. RESULTS: Better performances were observed in Group S in both retention-test 1 (Group V: 63.2 [52.6, 77.6] vs. Group S: 89.5 [68.4, 100.0], P < 0.001) and retention-test 2 (Group V: 58.0 [48.0, 72.0] vs. Group S: 74.0 [64.0, 80.0], P < 0.001) compared to Group V. No statistically significant differences were observed in the performances of pre-test (Group V: 8.3 [4.2, 12.5] vs. Group S: 8.3 [4.2, 12.5], P = 0.825) or post-test (Group V: 46.2 [38.5, 57.7] vs. Group S: 44.2 [38.5, 56.7], P = 0.694) between the two groups. The improvement had been observed in the post-test, compared with pre-test in the same group, respectively (Group V in post-test: 46.2 [38.5, 57.7] vs. Group V in pre-test: 8.3 [4.2, 12.5], P < 0.001; Group S in post-test: 44.2 [38.5, 56.7] vs. Group S in pre-test: 8.3 [4.2, 12.5], P < 0.001). However, the performance in retention-test 2 was significantly reduced, compared with retention-test 1 in the same group, respectively (Group V in retention-test 2: 58.0 [48.0, 72.0] vs. Group V in retention-test 1: 63.2 [52.6, 77.6] P = 0.005; Group S in retention-test 2: 74.0 [64.0, 80.0] vs. Group S in retention-test 1: 89.5 [68.4, 100.0], P < 0.001). CONCLUSIONS: Following a 90-min theoretical lecture, simulation-based training better enhanced the performance of medical students in the interpretation and short-term retention of 20 cross-sectional views compared to video-based training. TRIAL REGISTRATION: http://www.chictr.org.cn ( ChiCTR2000033519 , 3/June/2020).

Antinociceptive effects of magnesium sulfate for monitored anesthesia care during hysteroscopy: a randomized controlled study.

BACKGROUND: Opioids are the most effective antinociceptive agents, they have undesirable side effects such as respiratory depressant and postoperative nausea and vomiting. The purpose of the study was to evaluate the antinociceptive efficacy of adjuvant magnesium sulphate to reduce intraoperative and postoperative opioids requirements and their related side effects during hysteroscopy. METHODS: Seventy patients scheduled for hysteroscopy were randomly divided into 2 groups. Patients in the magnesium group (Group M) received intravenous magnesium sulfate 50 mg/kg in 100 ml of isotonic saline over 15 min before anesthesia induction and then 15 mg/kg per hour by continuous intravenous infusion. Patients in the control group (Group C) received an equal volume of isotonic saline as placebo. All patients were anesthetized under a BIS guided monitored anesthesia care with propofol and fentanyl. Intraoperative hemodynamic variables were recorded and postoperative pain scores were assessed with verbal numerical rating scale (VNRS) 1 min, 15 min, 30 min, 1 h, and 4 h after recovery of consciousness. The primary outcome of our study was total amount of intraoperative and postoperative analgesics administered. RESULTS: Postoperative serum magnesium concentrations in Group C were significantly decreased than preoperative levels (0.86 ± 0.06 to 0.80 ± 0.08 mmol/L, P = 0.001) while there was no statistical change in Group M (0.86 ± 0.07 to 0.89 ± 0.07 mmol/L, P = 0.129). Bradycardia did not occur in either group and the incidence of hypotension was comparable between the two groups. Total dose of fentanyl given to patients in Group M was less than the one administered to Group C [100 (75-150) vs 145 (75-175) µg, median (range); P < 0.001]. In addition, patients receiving magnesium displayed lower VNRS scores at 15 min, 30 min, 1 h, and 4 h postoperatively. CONCLUSIONS: In hysteroscopy, adjuvant magnesium administration is beneficial to reduce intraoperative fentanyl requirement and postoperative pain without cardiovascular side effects. Our study indicates that if surgical patients have risk factors for hypomagnesemia, assessing and correcting magnesium level will be necessary. TRIAL REGISTRATION: ChiCTR1900024596 . date of registration: July 18th 2019.

Metformin attenuates increase of synaptic number in the rat spinal dorsal horn with painful diabetic neuropathy induced by type 2 diabetes: a stereological study.

In our previous study, we have shown that number of synapses in the L5 segment of spinal dorsal horn increased significantly in a rat model of painful diabetic neuropathy (PDN) induced by high-dose of streptozotocin (an animal model of type 1 diabetes). The aims of this study were: (1) to determine whether high fat diet/low dose streptozotocin-diabetes, a rat model for type 2 diabetes, related PDN was also associated with this synaptic plasticity, (2) to reveal the range of this synaptic plasticity change occurred (in the whole length of spinal dorsal horn or only in the L5 lumbar segment of spinal dorsal horn) and (3) to discover whether treatment with metformin had effect on this synaptic plasticity. Male adult Sprague-Dawley rats were randomly allocated into the control group (n = 7), the PDN group (n = 6) and the PDN treated with metformin (PDN + M) group (n = 7), respectively. 28 days after medication, synaptic and neuronal numbers in the whole length of spinal dorsal horn or in 1 mm length of the L5 segment of spinal dorsal horn were estimated by the optical disector (a stereological technique). Compared to the control group and the PDN + M group, number of synapses in the L5 segment of spinal dorsal horn increased significantly in the PDN group (P < 0.05). There was no significant change between the control group and the PDN + M group in terms of the parameters in the L5 segment of the spinal dorsal horn (P > 0.05). Parameters of the whole length of spinal dorsal horn showed no significant changes (P > 0.05). Our results suggest that high fat diet/low dose streptozotocin diabetes related PDN is also associated with a numerical increase of synapses in the L5 segment of spinal dorsal horn but not in the whole length of spinal dorsal horn. Furthermore, the analgesic effect of metformin against PDN is related to its inhibition of numerical increase of synaptic number in the rat spinal dorsal horn.

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.

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.

Effects of electroconvulsive stimulation on long-term potentiation and synaptophysin in the hippocampus of rats with depressive behavior.

OBJECTIVES: To evaluate the effects of electroconvulsive stimulation (ECS) on long-term potentiation (LTP) and synaptophysin (SYP) in the hippocampus of rats under chronic unpredictable mild stress (CUMS). METHODS: Sixty Sprague-Dawley rats were randomly divided into three groups (n=20 for each group): the control group (no intervention), the CUMS group (subjected to 28 days of CUMS exposure followed by 7 days of mock ECS treatment), and the CUMS+ECS group (subjected to 28 days of CUMS exposure followed by 7 days of ECS treatment). Depressive behavior was assessed by a sucrose preference test and an open-field test. The LTP levels in rat hippocampal slices were examined through electrophysiological experiments. The SYP mean density in the hippocampal CA3 region was detected by immunohistochemistry. Hippocampal SYP mRNA was assessed through reverse transcriptase-polymerase chain reaction. RESULTS: Chronic unpredictable mild stress diminished sucrose preference and reduced measures of locomotor activity. In addition, CUMS impaired LTP in the hippocampal CA1 region and significantly decreased SYP mean density in the hippocampal CA3 region and hippocampal SYP mRNA levels. Electroconvulsive stimulation improved these harmful behavioral effects and ameliorated LTP impairment, as well as stabilized SYP mean density in the hippocampal CA3 region and hippocampal SYP mRNA levels. CONCLUSIONS: These results suggest that ECS can reverse the harmful behavioral effects of CUMS in rats and that the behavioral alterations induced by ECS and/or CUMS may be associated with hippocampal neuroplasticity and SYP levels.

ß-Hydroxybutyrate Attenuates Painful Diabetic Neuropathy via Restoration of the Aquaporin-4 Polarity in the Spinal Glymphatic System.

Waste removal is essential for maintaining homeostasis and the normal function of the central nervous system (CNS). The glymphatic system based on aquaporin-4 (AQP4) water channels on the endfeet of astrocytes is recently discovered as the excretion pathway for metabolic waste products of CNS. In the CNS, α-syntrophin (SNTA1) directly or indirectly anchors AQP4 in astrocyte membranes facing blood vessels. Studies have indicated that ß-hydroxybutyrate (BHB) can raise the expression of SNTA1 and thus restoring AQP4 polarity in mice models with Alzheimer's disease. The study aims to evaluate the neuroprotective mechanism of BHB in rats with painful diabetic neuropathy (PDN). PDN rats were modeled under a high-fat and high-glucose diet with a low dose of streptozotocin. Magnetic resonance imaging (MRI) was applied to observe the clearance of contrast to indicate the functional variability of the spinal glymphatic system. Mechanical allodynia was assessed by paw withdrawal threshold. The expressions of SNTA1 and AQP4 were tested, and the polarity reversal of AQP4 protein was measured. As demonstrated, PDN rats were manifested with deceased contrast clearance of the spinal glymphatic system, enhanced mechanical allodynia, lower expression of SNTA1, higher expression of AQP4, and reversed polarity of AQP4 protein. An opposite change in the above characteristics was observed in rats being treated with BHB. This is the first study that demonstrated the neuroprotective mechanism of BHB to attenuate PDN via restoration of the AQP4 polarity in the spinal glymphatic system and provides a promising therapeutic strategy for PDN.

Stereological study on the numerical plasticity of myelinated fibers and oligodendrocytes in the rat spinal cord with painful diabetic neuropathy.

Painful diabetic neuropathy may associate with nerve morphological plasticity in both peripheral and central nervous system. The aim of this study was to determine numerical changes of myelinated fibers in the spinothalamic tract region and oligodendrocytes in the spinal dorsal horn of rats with painful diabetic neuropathy and the effects of metformin on the above changes. Male Sprague-Dawley rats were randomly allocated into the control group (n = 7), the painful diabetic neuropathy group (n = 6) and the painful diabetic neuropathy treated with metformin group (the PDN + M group, n = 7), respectively. Twenty-eight days after medication, numbers of myelinated fibers in the spinothalamic tract and oligodendrocytes in the spinal dorsal horn were estimated by the optical disector (a stereological technique). Compared to the control group, number of myelinated fibers in the spinothalamic tract increased significantly in the painful diabetic neuropathy and PDN + M group, compared to the painful diabetic neuropathy group, number of myelinated fibers decreased in the PDN + M group (P < 0.05). As the oligodendrocyte in the spinal dorsal horn was considered, its number increased significantly in the painful diabetic neuropathy group compared to the control and the PDN + M group (P < 0.05), there was no significant difference between the control and the PDN + M group (P > 0.05). Our results indicate that painful diabetic neuropathy is associated with a serial of morphometric plasticity in the rat spinal cord including the numerical increase of the myelinated fibers in the spinothalamic tract and the oligodendrocytes in the spinal dorsal horn. The analgesic effect of metformin against painful diabetic neuropathy might be related to its adverse effects on the above morphometric plasticity.

Effects of epidural combined with general anesthesia versus general anesthesia on quality of recovery of elderly patients undergoing laparoscopic radical resection of colorectal cancer: A prospective randomized trial.

STUDY OBJECTIVES: The aim of the present study was to assess the quality of recovery from anesthesia on patients subjected to laparoscopic radical resection of colorectal cancer under epidural block combined with general anesthesia or general anesthesia by means of Quality of Recovery-15 (QoR-15) questionnaire. DESIGN: Prospective randomized trial. SETTING: The setting is at an operating room, a post-anesthesia care unit, and a hospital ward. PATIENTS: Seventy patients, aging from 65 to 79 years with an American Society of Anesthesiologists physical status II or III, were scheduled to undergo laparoscopic radical resection of colorectal cancer. INTERVENTIONS: Epidural block combined with general anesthesia or general anesthesia. MEASUREMENTS: The QoR-15 was administered by an investigator blind to group allocation before surgery (T0), at 24 and 72h after surgery (T1 and T2), and on postoperative day 7 (T3). The quality of recovery, as assessed by the score on the QoR-15, was compared between the groups. Besides, the consumption of anesthetics, respiratory recovery time, response time, extubation time, flatus time, the incidence of nausea or vomiting, the consumption of antiemetic and analgesic agents, and the duration of the hospital stay were also recorded. MAIN RESULTS: The QoR-15 scores at T1 and T2 were significantly higher in the E + G group compared with the G group (P < 0.05). Among the five dimensions of the QoR-15, physiological comfort, physiological independence, pain, and emotional dimension were significantly better at T1 in the E + G group, and physiological comfort and pain were significantly better at T2 in the E + G group. CONCLUSION: This study demonstrates that epidural block combined with general anesthesia can improve the early recovery of elderly patients after laparoscopic radical resection of colorectal cancer from the perspective of patients.

Stereological study on the number of synapses in the rat spinal dorsal horn with painful diabetic neuropathy induced by streptozotocin.

Our previous studies showed that direct injury to the sciatic nerve (chronic constriction injury or axotomy) is associated with a numerical increase in synaptic number in the rat spinal dorsal horn. The aim of this study was to determine whether painful diabetic neuropathy (PDN) was also associated with numerical changes in the synaptic or neuronal numbers in the spinal dorsal horn. Overall, 17 adult SD rats were allocated randomly into the control group (n=5) and the streptozotocin (STZ) group (n=12). STZ was injected intraperitoneally to induce diabetes. In the STZ group, seven rats (STZ-H) showed hyperglycemia (fasting blood glucose >11.1 mM) and the rest of the five rats (STZ-N) did not. Rats were fed and observed for 28 days after hyperglycemia. Two of the seven STZ-H rats died of infection during the observation period. Body weight and paw withdraw threshold (PWT) decreased in the rest of the five STZ-H rats. Twenty-eight days after hyperglycemia, the L5 segment of the spinal cord was removed; paraffin-embedded sections were prepared and stained with Nissl's method and synaptophysin immunohistochemistry, respectively. The optical dissector (a stereological technique) was used to estimate the numbers of neurons and synapses in the spinal dorsal horn. Compared with the control group, the synaptic number and ratio between the numbers of synapses and neurons in the L5 segment of the spinal dorsal horn were increased significantly in the STZ-H rats (P<0.05), whereas the neuronal number did not change significantly (P>0.05). Parameters of STZ-N rats showed no significant changes. In conclusion, PDN, a form of neuropathic pain, is also associated with a synaptic plasticity (numerical increase) in the spinal dorsal horn. This numerical change might be the reason for central sensitization resulting in reduced pain threshold, enhanced responsiveness, and expanded receptive fields associated with PDN. Therefore, our studies indicate that neuropathic pain conditions with different etiologies might show the same synaptic numerical plasticity changes.

Number of synapses increased in the rat spinal dorsal horn after sciatic nerve transection: a stereological study.

We recently found that the number of synapses in the spinal dorsal horn, as estimated by stereological techniques, increased by 86% after chronic constriction injury of sciatic nerve in rats. In this study, we aimed to reveal whether transection of sciatic nerve was also associated with a plasticity change in the number of synapses. 18 adult SD rats were randomly divided into 3 groups undergoing (i) unilateral sham operation, (ii) unilateral sciatic nerve transection, and (iii) unilateral sciatic nerve transection with postoperative medication (parecoxib) for 3 days, respectively. 28 days postoperation, the L4-6 segment of the spinal cord was removed; paraffin-embedded sections were prepared and stained with Nissl's method and synaptophysin immunohistochemistry. The optical disector (a contemporary stereological technique) was used to estimate the numbers of neurons and synapses in the spinal dorsal horn. Compared to the non-operated side, the axotomy induced a 74.3% increase in the number of synapses per unit length of spinal cord or a 67.4% increase in the ratio between the numbers of synapses and neurons in the middle tissue block from the L4-6 segment on the operated side but not in either the rostral or caudal tissue block. Parecoxib had no effect on the parameters. In conclusion, peripheral nerve injury, model for neuropathic pain, is associated with a synaptic plasticity (numerical increase) in the spinal dorsal horn.

[Human chorionic gonadotrophin on the expression of epidermal growth factor in rat renal tissues].

AIM: To investigate hCG on the expression of epidermal growth factor (EGF) in renal tissues. METHODS: 20 male SD rats weighed 300 - 350 g were injected hCG 200 IU/d for 7 days, and 20 male rats were injected sa-line at equal volume as a control. Kidney tissues were per-formed with immunohistochemical staining to evaluate the distribution of EGF and quantitative PCR (Q-PCR) was used to evaluate the EGF mRNA. RESULTS: Immunohistochemtry showed that the positive rate of EGF in experimental group was significantly higher than that in control group(P<0.01), but Q-PCR results showed no significant difference between two groups ( P > 0. 05). CONCLUSION: hCG increased the concentration of EGF by maturing pre-pro-EGF not expressing EGF from de novo synthesis.

Plasticity in the synaptic number associated with neuropathic pain in the rat spinal dorsal horn: A stereological study.

This study aimed to determine whether neuropathic pain is associated with a plasticity change in the number of synapses in the spinal dorsal horn. 12 normal adult SD rats were randomly divided into two groups: 7 animals were subjected to unilateral loose ligation (to induce chronic constriction injury) of the sciatic nerve (CCI group) and 5 animals subjected to unilateral sham-operation (sham-operated group). 28 days after operation, the L4-L6 segment of the spinal cord was removed, and paraffin-embedded sections were prepared and stained with Nissl's method and synaptophysin immunohistochemistry. The numbers of neurons and synapses in the spinal dorsal horn were estimated using a contemporary stereological technique-the optical disector. An 86% increase in the number (per unit length of the spinal cord) of synapses or 98% increase in the ratio between the numbers of synapses and neurons in the spinal dorsal horn was found in the middle tissue block but not in both the rostral and caudal tissue blokes cut from L4-L6 segment of the spinal cord. The results suggest that neuropathic pain, as established by the CCI model, is associated with a plasticity change in the spinal dorsal horn: increase in the number of synapses.