Autologous Platelet-rich Gel For Meniscus Injury And Repair Of Rabbits In The Avascular Zone

Objective:Through the construction of meniscus injury model of rabbits in the avascular zone, observed healing-promoting properties of fibrin glue and Autologous platelet-rich gel for meniscal injury, explored healing ability of meniscus injury in different interventions, then provided practical data of meniscal injury and repair in the avascular zone.Methods:36 adult New Zealand white rabbits were randomly divided into three groups of ABC, all experimental animals were operated by a full-thickness tear within the avascular zone of the menisci, that was about 0.5mm in diameter,0.1mm in transverse diameter. In A group, no any filler was applied for full-thickness tear; In B group,fibrin glue was infused in full-thickness tear;In C group, Autologous platelet-rich gel were infused in full-thickness tear. 4 rabbits of each group are killed at 4,8 and 12 weeks after operation, all menisci were collected in each group for general morphological observation,optical microscope,Transmission electron microscopic and Scanning electron microscopic observation.Results:Control group (A group): meniscus tears have never healed in general observation, the menisci were becoming thin and loss elasticity along with time passing. The micromorphological observation showed cell low metabolic state at 4 weeks; At 8 weeks showed cell number decreasing, no cell proliferation; At 12 weeks showed cell number further decreasing, extracellular matrix arranged in disorder, degeneration occurred. Fibrin glue (B group): at 4 weeks, meniscus defects becomed smaller, implantation of fibrin gel still existed, the spatial structure of fibrin gel becomed loose, some collagenous fiber can be seen occasionally; At 8 weeks, fibrin gel newly disappeared, meniscal defects closed, micromorphological observation showed collagenous fiber formation, which was connected with meniscal tissue; At 12 weeks the surface defects is nearly disappeared, micromorphological observation showed that defects was filled with collagenous fiber, but there is no chondrocyte had been found, that suggesting scar-like healing in this group. Autologous platelet-rich gel (C group): at 4 weeks, meniscus defects have been filled, the Autologous platelet-rich gel can be seen occasionally, micromorphological observation showed cell proliferation activative; At 8 weeks, the gel disappeared, defects closed, It can be seen scattered chondrocyte and collagen formation in microscope; At 12 weeks, the defects become a little and small depression, there was chondrocyte proliferation and collagen formation, the reparative tissue connected with normal tissue with collagenous fiber, that suggesting fibrocartilage-like healing in this group. But the collagen fibers arranged in disorder, the characteristics of healing tissue was different from normal tissue.Conclusion:1. Avascular zone of meniscus can not be natural healing after injury, the damage can cause the meniscal degeneration.2. Fibrin glue had the effect of promoting the healing of meniscal injury in the avascular zone, the reparative tissue is scar-like healing.3. Autologous platelet-rich gel can also promote healing of meniscal injury in the avascular zone, but the reparative tissue was fibrocartilage-like, which were different from the normal tissues.4. Preliminary study suggested that, the reparative effect of autologous platelet-rich gel is better than fibrin glue on meniscal repair in the avascular zone.