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.