RESUMO
Objective To observe expression levels of N-methyl-D-aspartate (NMDA) receptor and cholecystokinin (CCK) in the hippocampus and spinal cord in morphine withdrawal or tolerance mice treated by electroacupuncture or catgut embedding and explore the difference between the regulating effects of electroacupuncture and catgut embedding on morphine withdrawal and tolerance.Methods Fifty-six male C57BL/6J mice were randomly allocated to withdrawal control, withdrawal model, withdrawal catgut embedding and withdrawal electroacupuncture groups, and tolerance control, tolerance model, tolerance catgut embedding and tolerance electroacupuncture groups, 7 mice in each group. A model of morphine withdrawal was made by subcutaneous injection of morphine hydrochloride using 7-day increasing addiction method. The withdrawal control group was injected with an equal volume of normal saline at the same time points. In the withdrawal electroacupuncture group, electroacupuncture at bilateral points Shenshu was performed using a Han’s acupoint nerve stimulation device (HANS-200) at 15 min after an injection of morphine hydrochloride. In the withdrawal catgut embedding group, 0.5 cm chromic catgut was embedded in bilateral points Shenshu at 15 min after an injection of morphine hydrochloride. Addiction was promoted by intraperitoneal injection of naloxone 4 mg/kg at 10 o’clock on the seventh day’s morning and Withdrawal reactions were observed in the mice. The score was recorded using the Ryuta Tomoji opioid withdrawal symptoms evaluation scale. NMDA receptor and CCK contents in the hippocampus and spinal cord were measured by enzyme-linked immunosorbent assay (ELISA). A model of morphine tolerance was made by subcutaneous injection of morphine 10 mg/kg. The tolerance control group was injected with tolerance normal saline 10 ml/kg at the same time. In the tolerance catgut embedding group, catgut was embedded in point Shenshu at the first day after model making. In the tolerance electroacupuncture group, point Shenshu was given electroacupuncture at the first day after model making. After seven days of treatment, NMDA receptor and CCK contents in the hippocampus and spinal cord were measured by ELISA.Results There were statistically significant differences in hippocampal NR2B and CCK expressions between the withdrawal model and withdrawal control groups (P<0.05). There was a statistically significant difference in hippocampal NR2B expression between the withdrawal electroacupuncture and withdrawal model groups (P<0.05). There was a statistically significant difference in hippocampal CCK expression between the withdrawal catgut embedding or withdrawal electroacupuncture group and the withdrawal model group (P<0.05). There were statistically significant differences in spinal cord NR2A, NR2B and CCK expressions between the withdrawal model and withdrawal control groups (P<0.05). There were statistically significant differences in spinal cord NR2A and NR2B expressions between the withdrawal electroacupuncture and withdrawal model groups (P<0.05). There were statistically significant differences in hippocampal NR2A, NR2B and CCK expressions between the tolerance model and tolerance control groups (P<0.05). There was a statistically significant difference in hippocampal CCK expression between the tolerance catgut embedding and tolerance model groups (P<0.05). There was a statistically significant difference in hippocampal NR1 expression between the tolerance electroacupuncture group and the tolerance model or tolerance catgut embedding group (P<0.05). There was a statistically significant difference in spinal cord CCK expression between the tolerance catgut embedding or withdrawal electroacupuncture group and the tolerance model group (P<0.05).Conclusions Both catgut embedding and electroacupuncture at point Shenshu have a reducing effect on morphine tolerance and withdrawal. The therapeutic effect of electroacupuncture is better than that of catgut embedding.