Objective:To retrospectively observe the effect of oxycodone on acute postoperative pain in patients undergoing thoracoscopic surgery.Methods:A retrospective analysis was conducted on the clinical data of 404 patients undergoing thoracoscopic thoracic surgery under combined general anesthesia at the Xiangya Hospital, Central South University from April 1, 2020 to September 30, 2021. They were divided into A group ( n=99, oxycodone group) and B group ( n=305, control group) based on whether oxycodone was used during the surgery. The two groups of patients were further matched 1∶1 using the nearest neighbor matching method. We compared the Visual Analogue Scale (VAS) of activity and resting pain and the incidence of moderate to severe pain between two groups of patients 24 hours after surgery, and observed the incidence and severity of pain related adverse reactions such as nausea, vomiting, itching, and dizziness. Resultsl:After matching the propensity scores of the two groups of patients, the balance was good ( SMD<0.20). There was no statistically significant difference between the groups in age, gender, body mass index, American Society of Anesthesiologist (ASA) grade, surgical time, intraoperative bleeding, and the use of antiemetics and analgesics during the perioperative period (all P>0.05). Compared with the control group, patients in the group A had a resting VAS [(2.03±1.61)points vs (1.62±1.31)points, P=0.049], and activity VAS [(4.13±1.72)points vs (3.51±1.79)points, P=0.013] was even lower, and the incidence of moderate to severe pain (VAS≥4) during activity was lower [59.6%(59/99) vs 37.4%(37/99), P=0.003]. There was no statistically significant difference in the incidence of analgesic related adverse reactions between the two groups ( P>0.05). Conclusions:Intravenous injection of oxycodone can effectively alleviate acute pain in patients undergoing thoracoscopic surgery within 24 hours, and reduce the incidence of moderate to severe pain during activity.

To explore the role of P2X4 receptor in opioid-induced hyperalgesia (OIH).
 Methods: A total of 30 Sprague-Dawley (SD) male rats were randomly divided into 5 groups: a saline (N0) group, a remifentanil at 0.5 μg/(kg.min) (R1) group, a remifentanil at 1.0 μg/(kg.min) (R2) group, a remifentanil at 1.5 μg/(kg.min) (R3) group, and a remifentanil at 5.0 μg/(kg.min) (R4) group. The paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) were measured at follow time points to optimize the dosages: the day before treatment (T1), 30 min after tail intravenous catheterization (T2), and 30 min (T3), 1 h (T4), 2 h (T5), 24 h (T6) after withdrawal from remifentanil. Then, the rats were randomly divided into 2 groups: a saline group (N group), a remifentanil at 1.0 μg/(kg.min) group (R group). The PWMT and PWTL were measured at follow time points: T1, T2, and T4. The lumbar enlargement of spine was selected at 1 h after withdrawal from remifentanil, and the expression of P2X4 receptor mRNA and protein was examined in OIH. Additional male rats were selected and randomly divided into 2 groups: a plantar incision surgery followed by saline treatment group (I+N group), a plantar incision surgery followed by remifentanil treatment group (I+R group). The PWMT and PWTL were measured at follow time points: T1, T2, T3, T4, T5, T6, 48 h (T7) and 72 h (T8) after withdrawal from remifentanil. The lumbar enlargement of spine was selected at 1 h after withdrawal from remifentanil, the expression of P2X4 receptor mRNA and protein was examined by PCR and Western blotting, and the microglial activation in spine 1 h after withdrawal from remifentanil were assessed by immunofluorescence.
 Results: The pain thresholds including PWMT and PWTL in different groups were as follows: R4 group Animals ; Hyperalgesia ; Male ; Pain, Postoperative ; Rats ; Rats, Sprague-Dawley ; Receptors, Purinergic P2X4 ; Remifentanil ; Spinal Cord