The prevention and treatment of heijingpaichitang for immune rejection following high-risk corneal transplantation in rats

Abstract

The rate of corneal graft rejection is still high for high-risk keratoplasty although immune suppression drug is routinely used.The role of traditional Chinese medicine in corneal transplantation is concerned gradually.Heijingpaichitang on the prevention and treatment of rats with high-risk corneal allograft rejection needs further study.Objective This study was to investigate the inhibitory effect of heijingpaichitang on high-risk corneal transplantation immune rejection in rats.Methods Sixteen female SD rats were used as the donors and 32female Wistar rats were served as recipients.The high-risk corneal trasplantation models were established by corneal suture in 32 Wistar rats,and then homogeneity variant SD-Wistar corneal transplantation was performed.The recipients were randomized into model control group,cyclosporinc A (CsA)group,heijingpaichitang group and CsA +heijingpaichitang group.CsA,heijingpaichitang and CsA + heijingpaichitang was orally administered 4 days after operation once per day for 15 days,and normal saline solution was used at the same way in the model control group.Ocular anterior segment reaction was examined under the slit lamp and corneal opacification,edema and neovasculation were scored based on Larkin' s criteria.Rejection index of the corneal graft was recorded and the graft survival time was calculated.The pathological examination of the corneal graft was carried out in all rats,and the inflammatory cells in the corneas and CD4+ cells in the periphery blood were assayed using flow cytometry.The use of the animals complied with ARVO Statement.Results Corneal graft rejection occurred in 10 days after operation in the model control group,12-13 days in the CsA group and heijingpaichitang group and 22 days in the CsA +heijingpaichitang group.Compared with model control group,the scores of the corneal opacification,corneal edema and neovascularization were significantly lower in the CsA group,heijingpaichitang group and CsA+heijingpaichitang group (P＜0.05),and all the scores were declined in the CsA+ heijingpaichitang group compared with CsA group and heijingpaichitang group(P＜0.01),but no significant differences were seen in the scores between the CsA group and heijingpaichitang group(P＞0.05).The mean survival time of grafts was (10.38 ±1.69)days in the model control group,(22.50 ± 3.07) days in the CsA + heijingpaichitang group,with the significant difference (t =-9.790,P =0.000).The pathological examination of graft showed that the lymphocytes and new blood vessels were less in the CsA+heijingpaichitang group compared with CsA group and heijingpaichitang group 15 days after operation.Flow cytometry verified that the number of lymphocytes in graft,CD4+cells and CD4+/CD8+ in periphery blood were significantly lower in the heijingpaichitang group,CsA group and CsA+heijingpaichitang group compared with model control group (P＜0.05).Conclusions Heijingpaichitang can inhibit immune rejection to certain extent in high-risk corneal transplantation rat and has a similar effect to 0.1％ CsA.Heijingpaichitang and 0.1％ CsA have a synergistic effect. Key words: Corneal transplantation/high-risk corneal transplantation; Immunne rejection; Traditional Chinese medicine; Chinese medicine