Hypoglycemic Effect of Acupoint Injection of Sustained-release Insulin at Different Times in SD Rats / 上海针灸杂志

ABSTRACT

Objective To observe blood glucose values and serum insulin levels at different times after acupoint injection of insulin with PVP as a sustained release agent and analyze the correlation between them in SD Rats.Methods One hundred and forty-four male SD rats were randomized into groups A (acupoint injection of insulin alone), B (acupoint injection of sustained-release insulin) and C (control). At one hour after every group received an oral gavage of 40% glucose solution (2.2 g/kg), groups A and B were given point Zusanli injection and group C was not treated. In the three groups of rats, blood glucose values and serum insulin levels were measured at six time points: 0.5, 3, 6, 8, 10 and 24 hours after acupoint injection (in group C at the corresponding time points). In every group, the reaction of Point Zusanli region to the stimulation was observed by optical microscopy in at three time points: 3, 10 and 24 hours after acupoint injection.Results The glucose-lowering rate reached its peak at 3 hours after acupoint injection and then declined in groups A and B. The hypoglycemic effect tended to be stable at 6 hours after acupoint injection in group A and at 10 hours after acupoint injection in group B. The hypoglycemic effect was better in group B than in group A at 6 and 8 hours after acupoint injection (P<0.01). In group A, serum insulin reached its peak at 3 hours and tended to be stable at 6 hours after acupoint injection (P<0.05). Serum insulin levels were significantly lower in group B than in group A at four time pints: 0.5, 3, 6 and 8 hours after acupoint injection (P<0.05). An analysis of the correlation between rat serum insulin levels and the glucose-lowering rate showed a significant positive correlation in group A (P<0.01) and a low positive correlation in group B (P<0.05). In groups A and B of rats, clear stripes and complete structure of muscle fibers were seen with no obvious degeneration, necrosis and inflammatory reaction around point Zusanli at three time points: 3, 8 and 24 hours after acupoint injection; there were no obvious pathological changes compared with group C.Conclusions PVP as a sustained release agent can slow down the absorption rate of insulin in rat point Zusanli region. Meanwhile, it prolongs the continuous time of the hypoglycemic effect of insulin. There is a low correlation between serum insulin levels and the hypoglycemic effect, suggesting that acupoint injection with a sustained release agent can prolong the effect of acupoint injection of medicine.