Abstract: Objective To evaluate the effect on immune parameters of rats and mice stressed by oral gavage, intraperitoneal injection and intramuscular injection. Method Wistar rats were used to establish oral gavage stressed model(IG_R)，intraperitoneal injection stressed model (IG_R) and intramuscular injection stressed model (IG_R)，immune function were assessed by measuring parameters including peripheral WBC and WSCR, serum levels of IL-2, IL-4, IFN-γ and the ratio of IFN-γ/IL-4. The changes of immune parameters in stressed rats were analyzed by comparing with relative control group. ICR mice were used to establish oral gavage stressed model (IG_m) and intraperitoneal injection stressed model(IP_m), peripheral WBC , WSCR，and serum levels of IL-2 were measured and compared with relative control group to discover immune changes in stressed mice. Results Compared to the control group, the levels of serum IL-2 and the number of peripheral WBC decreased in the stressed rats while IFN-γ production and IFN-γ/IL-4 ratio increased. IP_R rats and IM_R rats had higher WSCR than the control group. The IL-2 production decreased in the stressed mice. IG_m mice had lower peripheral WBC number and WSCR while IP_m mice had higher peripheral WBC number when compared to the relative control ones. Conclusion Immune imbalance may be induced in laboratory rat and mouse stressed by oral gavage, intraperitoneal injection and intramuscular injection, mostly a decreased levels of IL-2 and WBC, increased IFN-γ, and T_h1 polarization are demonstrated in the stressed animals.

Key words: Dosing stress, Immunological index, Disturb, Rat, Mouse