Efeito do Plasma Rico em Plaquetas na apoptose pós-traumática de condrócitos

Platelet-rich plasma inhibits inflammatory factors and represses rheumatoid fibroblast-like synoviocytes in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic disease affecting daily life of numerous patients, and uncontrolled proliferation of synovial fibroblasts plays vital role during the pathology of RA. Platelet-rich plasma (PRP), widely used in tissue regeneration and pain management, is rarely studied in RA. This study aims to investigate the effect of PRP on synovial fibroblasts during RA. Rheumatoid fibroblast-like synoviocyte MH7A cells were stimulated by lipopolysaccharide (LPS) to simulate RA conditions and treated with PRP, after that the concentration of inflammatory factors interleukin (IL) 1β, tumor necrosis factor alpha (TNFα) and IL6 in the supernatant of culture medium was quantified by ELISA. MTT assay, flow cytometry and tube formation assay were performed to assess changes in cell viability, apoptosis and effect on angiogenesis in vitro, respectively. Besides, the expression levels of main factors in the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signal pathway were examined. Results showed that PRP markedly inhibited the production of IL1β, TNFα and IL6 (P < 0.05) that was stimulated by LPS. LPS promoted MH7A cell viability, inhibited apoptosis and accelerated angiogenesis in vitro, while PRP could markedly relieve these effects (P < 0.05). The mRNA and protein levels of AKT1, PI3K (p58) and nuclear factor κ beta were elevated by LPS and then suppressed by PRP (P < 0.01). This study uncovered the potential of PRP in inhibiting inflammation, repressing synovial fibroblasts and regulating the PI3K/AKT signaling, providing basic proof for future application of PRP in managing RA. Further investigation is necessary to reveal detailed mechanism of PRP.

Effects of heterologous platelet-rich plasma gel on standardized dermal wound healing in rabbits

PURPOSE

To evaluate the potential of heterologous platelet-rich plasma (PRP) gel for surgical skin wound healing in rabbits.

METHODS

Blood from a single healthy dog was used for PRP production, with calcium gluconate added to the PRP to form the gel. Two surgical excisions, one to the right and the other to the left of the dorsal midline, were made in six rabbits. One side was randomly allocated to topical application of a physiological solution, and the other was allocated to treatment with heterologous PRP gel. Clinical assessments (weight, pain sensitivity, coloring, edema, hyperemia, exudation, crust, and granulation) and morphometric evaluations were performed 0, 3, 7, 10, 14, and 17 days postoperatively. Histological analysis was performed on the 17th day.

RESULTS

With the exception of the presence of a crust at day 10, clinical variables did not differ significantly between the experimental groups. In both the control and PRP-treated groups, differences were identified when comparing time-points in terms of wound area reduction. Histological results indicated no significant differences between the control group and the PRP-treated group.

CONCLUSION

Heterologous platelet-rich plasma gel promoted dermal wound healing in rabbits with no adverse effects.

Effect of hyaluronic acid on chondrocyte apoptosis

OBJECTIVE:

To determine the percentage of apoptotic cells in a contusion model of osteoarthritis (OA) and to assess whether intra-articular injection of high doses of hyaluronic acid (HA) immediately after trauma reduces chondrocyte apoptosis.

METHODS:

Forty knees from adult rabbits were impacted thrice with a 1 kg block released through a 1 meter tall cylinder (29.4 Joules). Subsequently, 2 mL of HA was injected in one knee and 2 mL saline in the contra-lateral knee. Medication were administered twice a week for 30 days, when animals were sacrificed. Specimens were prepared for optical microscopy exam and terminal deoxynucleotidyl transferase end labeling assay (TUNEL).

RESULTS:

The apoptosis rate in the contusion model was 68.01% (± 19.73%), a higher rate than previously described. HA significantly reduced the rate of apoptosis to 53.52% (± 18.09) (p <0.001).

CONCLUSION:

Intra-articular HA administration started immediately after trauma reduces impact-induced chondrocyte apoptosis rates in rabbits.

Level of Evidence I, Experimental Study.

Comparison of experimentally-induced wounds in rabbits treated with different sources of platelet-rich plasma

Over the years, autologous platelet-rich plasma (PRP) has been used to great advantage in the healing of acute and chronic wounds. However, it is impossible to use in some situations so alternative PRPs need to be considered, such as homologous or heterologous PRPs. In order to evaluate the effects of PRP in the form of autologous, heterologous and homologous gels on in vivo cutaneous wound healing, 18 animals divided into three groups of six, were used for the study, with another six animals used as PRP donors. For the heterologous group an adult, mixed breed dog was used to obtain the PRP. The wounds were induced using an 8 mm punch. The left side was treated with NaCl 0.9%® (A) and a PRP gel was applied (GA = autologous; GHE = heterologous and GHO = homologous) on the right side (B). The wounds were evaluated for a period of 17 days. On the 17th day biopsies were taken for histopathological assessment of the wounds. The percentage of contraction was evident in side B (treated), which was confirmed in the microscopic analysis of the histological sections. Thus, it was concluded that PRP, regardless of the source, improves and accelerates the healing process, demonstrating its therapeutic potential on cutaneous lesions and its use in patients with impaired wound healing.

Treatment of osteochondral injuries with platelet gel

OBJECTIVES

Treatments for injured articular cartilage have not advanced to the point that efficient regeneration is possible. However, there has been an increase in the use of platelet-rich plasma for the treatment of several orthopedic disorders, including chondral injuries. Our hypothesis is that the treatment of chondral injuries with platelet gel results in higher-quality repair tissue after 180 days compared with chondral injuries not treated with gel.

METHODS

A controlled experimental laboratory study was performed on 30 male rabbits to evaluate osteochondral injury repair after treatment with or without platelet gel. Osteochondral injuries were surgically induced in both knees of each rabbit at the medial femoral condyle. The left knee injury was filled with the platelet gel, and the right knee was not treated. Microscopic analysis of both knee samples was performed after 180 days using a histological grading scale.

RESULTS

The only histological evaluation criterion that was not significantly different between treatments was metachromasia. The group that was treated with platelet gel exhibited superior results in all other criteria (cell morphology, surface regularity, chondral thickness and repair tissue integration) and in the total score.

CONCLUSION

The repair tissue was histologically superior after 180 days in the study group treated with platelet gel compared with the group of untreated injuries.