Abstract: Objective To establish a mouse model of allergic conjunctivitis by intraperitoneal injection of ovalbumin (OVA) and ovalbumin eye drops. Design Experimental study. Participants 20 SPF BALB/c mice aged 6~8 weeks. Methods 20 BALB/c mice were randomly divided into normal control group (PBS group) and allergic conjunctivitis group (OVA group). OVA group was intraperitoneally injected with 200 μl ovalbumin sensitizing solution on day 0, 2, 4, 6 and 8. On the 10th, 11th, 12th, 13th and 14th day, 10 μl ovalbumin solution drops was applied to the eyes of mice respectively. In PBS group, the intraperitoneal injection and eye drops were replaced with PBS. The ocular surface state was evaluated 15~30 minutes after the allergic provocation solution was applied. Animals were sacrified by euthanasia on the 15th day, Giemsa staining and immunohistochemistry (IHC) staining revealed pathological change. The typical manifestations of allergic conjunctivitis, including lid edema, conjunctival redness, chemosis, tearing, and frequent scratching were examined with a slit lamp. On the 15th day, the spleen was separated, the weight of spleen was weighed, and the spleen index was calculated. The expression of interleukin (IL)-8, IL-6 and thyonic stromal lymphopoietin (TSLP) was detected by immunohistochemistry, and the infiltration of inflammatory cells was evaluated by Giemsa staining. Main Outcome Measures The symptom score of allergic conjunctivitis, the number of eyes scratching, spleen index, the expression of IL-8, IL-6, TSLP and inflammatory cells infiltration. Results The survival rate of OVA group was 100%. Compared with PBS group, the mice in OVA group showed obvious splenomegaly, eyelid edema, hyperemia and epiphora. The symptom scores of OVA group and PBS group were 3.1±1.45, 6.6±1.71, 5.7±1.34, 6.4±1.51, 10.1±1.66 and 1.3±0.95, 1.9±0.99, 1.7±0.82, 1.3±1.06, 1.4±0.84 on day 10, 11, 12, 13 and 14, respectively (all P<0.05); the times of eye scratching in two groups were 28.8±5.88, 29.3±7.42, 27.2±8.2, 28.0±6.82, 26.2±5.09 and 12.3±4.32, 12.7±5.03, 13.3±5.62, 12.7±5.54, 16.4±2.67, respectively (all P<0.05). On day 15, the spleen index of OVA group and PBS group were 6.67±0.66 and 4.21±0.40 respectively (t=10.02, P=0.0001). The average optical density of TSLP in PBS group and OVA group was 10.23±1.52 and 20.25±1.75 (t=7.482, P=0.0017), the average optical density of IL-6 was 13.15±1.68 and 24.93±3.02 (t=5.911, P=0.0041), and the average optical density of IL-8 was 12.23±3.22 and 22.12±4.00 (t=3.337, P=0.0289). The results of Giemsa staining showed that eosinophil infiltration was observed in the conjunctival tissue of OVA group. The eosinophil count in the conjunctival tissue of PBS group and OVA group was 266.67±57.74/mm2 and 1366.67±57.74/mm2 respectively (t=23.33, P=0.0001). Conclusion The mouse model of allergic conjunctivitis was successfully established by intraperitoneal injection of ovalbumin and repeated eye stimulation, which can provide a simple and reliable experimental tool for the mechanism research and drug development of human allergic conjunctivitis. (Ophthalmol CHN, 2021, 30: 189-194)

Key words: allergic conjunctivitis, mouse model, ovalbumin