OBJECTIVE: To investigate the effect of autologous osteochondral tissue and periosteum transplantation on tendon-bone healing of rotator cuff in rabbits. METHODS: Twenty-four male New Zealand white rabbits were randomly divided into autologous osteochondral tissue and periosteum transplantation group (experimental group, n=12) and simple suture group (control group, n=12). Both groups were subjected to acute supraspinatus tendon injury and repaired with corresponding techniques. At 4, 8, and 12 weeks after operation, 4 specimens from each group were taken from the right shoulder joint for histological examination (HE staining, Masson staining, and Safranin O-fast green staining), and the left shoulder was subjected to biomechanical tests (maximum tensile load and stiffness). RESULTS: Both groups of animals survived until the completion of the experiment after operation. At 4 weeks after operation, both groups showed less collagen fibers and disorder at the tendon-bone junction. At 8 weeks, both groups showed reduced inflammation at the tendon-bone junction, with more organized and denser collagen fibers and chondrocytes. The experimental group showed better results than the control group. At 12 weeks, the experimental group showed typical tendon-bone transition structure, with increased generation of collagen fibers and chondrocytes, and the larger cartilage staining area. Both groups showed an increase in maximum tensile load and stiffness over time ( P<0.05). The stiffness at 4 weeks and the maximum tensile load at 4, 8, and 12 weeks in the experimental group were superior to control group, and the differences were significant ( P<0.05). There was no significant difference in stiffness at 8, 12 weeks between the two groups ( P>0.05). CONCLUSION Autologous osteochondral tissue and periosteum transplantation can effectively promote the fiber and cartilage regeneration at the tendon-bone junction of rotator cuff and improve the biomechanical effect of shoulder joint in rabbits.
Animals ; Rabbits ; Male ; Wound Healing ; Transplantation, Autologous ; Periosteum/transplantation* ; Rotator Cuff Injuries ; Rotator Cuff/surgery* ; Tendons/surgery* ; Biomechanical Phenomena ; Chondrocytes/transplantation* ; Tendon Injuries/surgery* ; Tensile Strength

OBJECTIVE: To investigate the effects of combined platelet-rich plasma (PRP) and arterial supercharging technique on the survival rate and functional restoration of cross-body region skin flaps in rabbits. METHODS: Twelve healthy 6-month-old New Zealand White rabbits were randomly assigned to 4 groups ( n=3): sham group, PRP group, anastomosis group, and combined treatment group. An axial skin flap with an area of 12 cm×6 cm on the inner side of the hind limbs of all animals were prepared, with the saphenous artery as the main blood supply. Following the ligation of both the proximal and distal ends of the saphenous artery across all groups, the sham group received no further intervention, the PRP group was subjected to PRP injection, the anastomosis group underwent in situ end-to-end anastomosis of the distal saphenous artery, and the combined treatment group received both in situ distal saphenous artery anastomosis and PRP administration. Flap survival was evaluated and recorded on postoperative days 1, 3, and 7, with survival rates calculated accordingly. On day 7, flap tissue samples were harvested for HE staining to assess basal tissue morphology. Additionally, immunohistochemical staining was conducted to detect the expression of α-smooth muscle actin (α-SMA), vascular endothelial growth factor (VEGF), and CD31 in the flap tissues. RESULTS: At postoperative day 1, no significant difference in flap survival rates were observed among the 4 groups ( P>0.05). At day 3, the PRP group showed no significant difference compared to the sham group ( P>0.05); however, both the anastomosis and combined treatment groups exhibited significantly higher survival rates than the sham group ( P<0.05), the combined treatment group further demonstrated superior survival rates compared to both the PRP and anastomosis groups ( P<0.05). At day 7, the combined treatment group maintained significantly higher survival rates than all other groups ( P<0.05), while both the PRP and anastomosis groups exceeded the sham group ( P<0.05). HE staining at day 7 revealed persistent inflammatory cell infiltration, sheet-like erythrocyte deposition, and disordered collagen fibers in the sham group. The PRP group showed nascent microvessel formation and early collagen reorganization, whereas the anastomosis group displayed mature microvasculature with resolved interstitial edema. The combined treatment group exhibited differentiated microvessels with densely packed collagen bundles. Immunohistochemical analysis at day 7 demonstrated significantly larger relative area percentages of α-SMA, VEGF, and CD31 positive cells in the combined treatment group compared to all other groups ( P<0.05). Both the PRP and anastomosis groups also showed significantly higher values than the sham group ( P<0.05). CONCLUSION The combination of PRP and arterial supercharging techniques significantly enhances flap healing, potentially through mechanisms involving augmented angiogenesis and improved blood supply.
Animals ; Rabbits ; Platelet-Rich Plasma ; Surgical Flaps/blood supply* ; Graft Survival ; Anastomosis, Surgical/methods* ; Ischemia/surgery* ; Arteries/surgery* ; Skin/blood supply* ; Vascular Endothelial Growth Factor A/metabolism* ; Male ; Skin Transplantation/methods*

OBJECTIVE: To explore clinical effect of autologous osteochondral transplantation (AOT) in the treatment of recurrent anterior dislocation of the shoulder joint with glenoid cartilage defect in rabbits by establishing a model of recurrent anterior dislocation of the shoulder joint with < 20% glenoid cartilage defect in rabbits. METHODS: Twenty-four male New Zealand white rabbits, aged 6-month-old, weighed (2.69±0.17) kg were selected. The labrum of shoulder joint of rabbits was artificially destroyed to establish a model of recurrent anterior dislocation of shoulder joint with cartilage defect. They were divided into AOT surgery group and simple suture group, with 12 rabbits in each group. AOT group were underwent AOT surgery, while simple suture group was treated with simple Bankart suture for recurrent shoulder joint dislocation. At 6 and 12 weeks after operation, 6 rabbits between two groups were sacrificed for sampling. The dietary conditions, activity conditions, mental states of rabbits and healing conditions of grafts in the specimens were observed and compared between two groups. HE staining was used to observe cell creep, cell morphology, inflammatory cell infiltration, fibrochondrocytes and their arrangement. Masson staining was used to observe the formation and arrangement of collagen fibers; Safrane-green staining was used to observe the regeneration of articular cartilage, subchondral bone and bone tissue. Bone mineral density (BMD), bone volume (BV) and trabecular thickness (Tb.Th) between two groups were measured by Micro-CT to evaluate the remodeling of shoulder glenoid bone defects by autologous osteochondral cartilage. RESULTS: After different surgical interventions were carried out in both groups of rabbits, at 6 weeks after the operation, the abduction, extension, internal rotation and external rotation of the shoulder joint on the operated side showed limited range of motion compared with the contralateral side, while adduction and forward flexion showed no obvious abnormalities compared with the contralateral side. At 12 weeks after operation, the range motion of tshoulder joints in both groups of rabbits had returned to the state before modeling. The effects of HE staining, Masson staining and safrane-green staining at 12 weeks after operation in both groups were stronger than the staining results at 6 weeks after operation. Moreover, the results of HE staining, Masson staining and safranin fixation green staining in AOT group at 6 and 12 weeks after operation were all higher than those in simple suture group. Micro-CT scan results at 6 and 12 weeks after operation showed that BMD (0.427±0.014), (0.466±0.032) g·cm-3, BV(116.171±3.527), (159.327±3.500) mm3, and Tb.Th (0.230±0.006), (0.285±0.009) mm in AOT group, which were higher than those of simple suture group in BMD(0.358±0.011), (0.384±0.096) g·cm-3, BV(72.657±3.903), (118.713±3.860) mm3, and Tb.Th(0.204±0.009), (0.243±0.007) mm;and the differences were statistically significant (P<0.05). CONCLUSION AOT procedure could effectively promote osteogenesis and fibrocartilage regeneration in the cartilage defect area of the shoulder glenoid <20%, which is conducive to reshaping the structure of the shoulder glenoid.
Animals ; Rabbits ; Male ; Transplantation, Autologous ; Cartilage, Articular/injuries* ; Shoulder Dislocation/physiopathology* ; Bone Transplantation ; Shoulder Joint/surgery*

OBJECTIVE: To investigate the biocompatibility of porous WE43 magnesium alloy scaffolds manufactured by 3D printing technology and to observe its effect in treating femoral defects in New Zealand white rabbits. METHODS: In vitro cytotoxicity test was performed using bone marrow mesenchymal stem cells from Sprague Dawley (S-D) rats. According to the different culture media, the cells were divided into 100% extract group, 50% extract group, 10% extract group and control group. After culturing for 1, 3 and 7 days, the cell activity of each group was determined by cell counting kit-8 (CCK-8). In the in vivo experiment, 3.0-3.5 kg New Zealand white rabbits were randomly divided into three groups: Experimental group, bone cement group and blank group, with 9 rabbits in each group. Each rabbit underwent surgery on the left lateral femoral condyle, and a bone defect with a diameter of 5 mm and a depth of 6 mm was created using a bone drill. The experimental group was implanted with WE43 magnesium alloy scaffolds, the bone cement group was implanted with calcium sulfate bone cement, and the blank group was not implanted. Then 4, 8 and 12 weeks after surgery, 3 rabbits in each group were euthanized by carbon dioxide anesthesia, and the femur and important internal organs were sampled. Micro-computed tomography (Micro-CT) scanning was performed on the left lateral femoral condyle. Sections of important internal organs were prepared and stained with hematoxylin-eosin (HE). Hard tissue sections were made from the left lateral femoral condyle and stained with methylene blue acid fuchsin and observed under a microscope. RESULTS: In the cytotoxicity test, the cell survival rate in the 100% extract group was higher than that in the control group (140.56% vs. 100.00%, P < 0.05) on 1 day of culture; there was no statistically significant difference (P>0.05) in cell survival rate among the groups on 3 days of culture; the cell survival rate in the 100% extract group was lower than that in the control group (68.64% vs. 100.00%, P < 0.05) on 7 days of culture. Micro-CT scanning in the in vivo experiment found that most of the scaffolds in the experimental group had been degraded in 4 weeks, with very few high-density scaffolds remaining. In 12 weeks, there was no obvious stent outline. In 4 weeks, a certain amount of gas was generated around the WE43 magnesium alloy scaffold, and the gas was significantly reduced from 8 to 12 weeks. Hard tissue sections showed that a certain amount of extracellular matrix and osteoid were generated around the scaffolds in the experimental group in 4 weeks. In the bone cement group, most of the calcium sulfate bone cement had been degraded. In 8 weeks, the osteoid around the scaffold and its degradation products in the experimental group increased significantly. In 12 weeks, new bone was in contact with the scaffold around the scaffold in the experimental group. There was less new bone in the bone cement group and the blank group. CONCLUSION The porous WE43 magnesium alloy scaffold fabricated by 3D printing process has good biocompatibility and good osteogenic properties, and has the potential to become a new material for repairing bone defects.
Animals ; Rabbits ; Printing, Three-Dimensional ; Alloys/chemistry* ; Tissue Scaffolds/chemistry* ; Magnesium/chemistry* ; Rats, Sprague-Dawley ; Biocompatible Materials ; Mesenchymal Stem Cells/cytology* ; Femur/surgery* ; Rats ; Absorbable Implants ; Male ; Bone Regeneration ; Tissue Engineering/methods* ; Cells, Cultured

OBJECTIVES: To investigate the effect of needle knife release on median nerve (MN) and transverse carpal ligament (TCL) morphology and function and expression levels of inflammatory factors in rabbit models of carpal tunnel syndrome (CTS). Methods Thirty adult New Zealand rabbits were randomized equally into control group, CTS model group, ultrasound-guided needle knife release group, needle knife release group without ultrasound guidance, and sham treatment groups. In all but the control group, the rabbits were subjected to CTS modeling by 10% glucose solution injection into the carpal tunnel once a week for 4 consecutive weeks, followed by interventions with a single treatment session. At 3 days and 30 days after the interventions, 3 rabbits from each group were selected for ultrasound measurement of TCL and MN thickness, electrophysiological testing, ultrasound elastography, and inflammatory cytokine level assessment. RESULTS: In the rabbit models of CTS, ultrasound-guided needle knife release significantly reduced the thickness of TCL and MN and improved sensory nerve conduction velocity at both 3 and 30 days after the intervention. Elastography of the TCL showed markedly softened intra-carpal tissues after ultrasound-guided needle knife release and achieved superior outcomes over those in the other groups. The treatment also significantly reduced IL-17 levels and lowered IL-6 and PGE2 expression at 30 days after the intervention. CONCLUSIONS Needle knife release of the TCL reduces thickness of the MN and TCL, enhances median nerve function, alleviates intrascatic tissue stiffness, and downregulates inflammatory factors in the carpal tunnel in rabbit models of CTS, and ultrasound guidance further enhances its therapeutic efficacy.
Animals ; Rabbits ; Carpal Tunnel Syndrome/surgery* ; Median Nerve/physiopathology* ; Disease Models, Animal

OBJECTIVE: To explore the effect of chitosan (CS) hydrogel loaded with tendon-derived stem cells (TDSCs; hereinafter referred to as TDSCs/CS hydrogel) on tendon-to-bone healing after rotator cuff repair in rabbits. METHODS: TDSCs were isolated from the rotator cuff tissue of 3 adult New Zealand white rabbits by Henderson step-by-step enzymatic digestion method and identified by multidirectional differentiation and flow cytometry. The 3rd generation TDSCs were encapsulated in CS to construct TDSCs/CS hydrogel. The cell counting kit 8 (CCK-8) assay was used to detect the proliferation of TDSCs in the hydrogel after 1-5 days of culture in vitro, and cell compatibility of TDSCs/CS hydrogel was evaluated by using TDSCs alone as control. Another 36 adult New Zealand white rabbits were randomly divided into 3 groups ( n=12): rotator cuff repair group (control group), rotator cuff repair+CS hydrogel injection group (CS group), and rotator cuff repair+TDSCs/CS hydrogel injection group (TDSCs/CS group). After establishing the rotator cuff repair models, the corresponding hydrogel was injected into the tendon-to-bone interface in the CS group and TDSCs/CS group, and no other treatment was performed in the control group. The general condition of the animals was observed after operation. At 4 and 8 weeks, real-time quantitative PCR (qPCR) was used to detect the relative expressions of tendon forming related genes (tenomodulin, scleraxis), chondrogenesis related genes (aggrecan, sex determining region Y-related high mobility group-box gene 9), and osteogenesis related genes (alkaline phosphatase, Runt-related transcription factor 2) at the tendon-to-bone interface. At 8 weeks, HE and Masson staining were used to observe the histological changes, and the biomechanical test was used to evaluate the ultimate load and the failure site of the repaired rotator cuff to evaluate the tendon-to-bone healing and biomechanical properties. RESULTS: CCK-8 assay showed that the CS hydrogel could promote the proliferation of TDSCs ( P<0.05). qPCR results showed that the expressions of tendon-to-bone interface related genes were significantly higher in the TDSCs/CS group than in the CS group and control group at 4 and 8 weeks after operation ( P<0.05). Moreover, the expressions of tendon-to-bone interface related genes at 8 weeks after operation were significantly higher than those at 4 weeks after operation in the TDSCs/CS group ( P<0.05). Histological staining showed the clear cartilage tissue and dense and orderly collagen formation at the tendon-to-bone interface in the TDSCs/CS group. The results of semi-quantitative analysis showed that compared with the control group, the number of cells, the proportion of collagen fiber orientation, and the histological score in the TDSCs/CS group increased, the vascularity decreased, showing significant differences ( P<0.05); compared with the CS group, the proportion of collagen fiber orientation and the histological score in the TDSCs/CS group significantly increased ( P<0.05), while there was no significant difference in the number of cells and vascularity ( P>0.05). All samples in biomechanical testing failed at the repair site during the testing process. The ultimate load of the TDSCs/CS group was significantly higher than that of the control group ( P<0.05), but there was no significant difference compared to the CS group ( P>0.05). CONCLUSION TDSCs/CS hydrogel can induce cartilage regeneration to promote rotator cuff tendon-to-bone healing.
Rabbits ; Animals ; Rotator Cuff/surgery* ; Chitosan ; Hydrogels ; Rotator Cuff Injuries/surgery* ; Wound Healing ; Tendons/surgery* ; Collagen ; Stem Cells ; Biomechanical Phenomena

OBJECTIVE: To observe the effect of needle-knife on the chondrocyte apoptosis of knee joint in rabbits with knee osteoarthritis (KOA) based on the CircSERPINE2-miR-1271-5P-E26 specific transformation-related gene (ERG) axis, and to explore the mechanism of needle-knife for KOA. METHODS: Thirty-six New Zealand white rabbits were randomly divided into a normal group, a model group, a needle-knife group and a sham needle-knife group, 9 rabbits in each group. The rabbits in the model group, the needle-knife group and the sham needle-knife group were treated with modified Videman method to prepare KOA model. After successful modeling, the rabbits in the needle-knife group were treated with needle-knife at cord adhesion and nodules near quadriceps femoris tendon and internal and external collateral ligament on the affected knee joint; the rabbits in the sham needle-knife group were treated with sham needle-knife baside the needle insertion point of the needle-knife group (needle-knife was only inserted, without any operation). The treatment was given once a week, 3 times in total. The Lequesne MG behavioral score was used to evaluate the knee joint damage in each group before and after intervention. After intervention, HE staining and transmission electron microscopy were used to observe the cartilage tissue morphology and ultrastructure of chondrocytes in the knee joint in each group; TUNEL method was used to detect the level of chondrocyte apoptosis in the knee joint; real-time fluorescence quantitative PCR was used to detect the expression of CircSERPINE2, miR-1271-5P and ERG mRNA in knee cartilage tissue in each group. RESULTS: After intervention, compared with the normal group, the Lequesne MG behavioral score in the model group was increased (P<0.01). Compared with the model group and the sham needle-knife group, the Lequesne MG behavioral score in the needle-knife group was decreased (P<0.01). In the model group and the sham needle-knife group, the number of chondrocytes and organelles was decreased, the cell nucleus was shrunk, mitochondria was swelling or disappeared; in the needle-knife group, the number of chondrocytes and organelles was increased, the cell nucleus was not obviously shrunk and the mitochondria was not obviously swelling. Compared with the normal group, the level of chondrocyte apoptosis in the model group was increased (P<0.01); compared with the model group and the sham needle-knife group, the level of chondrocyte apoptosis in the needle-knife group was decreased (P<0.01, P<0.05). Compared with the normal group, the expression of CircSERPINE2 and ERG mRNA in the model group was decreased (P<0.01), and the expression of miR-1271-5P mRNA was increased (P<0.01); compared with the model group and the sham needle-knife group, the expression of CircSERPINE2 and ERG mRNA in the needle-knife group was increased (P<0.01), and the expression of miR-1271-5P mRNA was decreased (P<0.01). CONCLUSION Needle-knife could reduce the knee joint damage and chondrocyte apoptosis in KOA rabbits, which may be related to up-regulating the expression of CircSERPINE2 and ERG mRNA, and inhibiting the expression of miR-1271-5P mRNA.
Rabbits ; Animals ; Osteoarthritis, Knee/metabolism* ; Chondrocytes/metabolism* ; Knee Joint/surgery* ; Apoptosis ; MicroRNAs/genetics*

OBJECTIVE: To explore the effect of a modified three-point bending fracture device for establishing a rabbit model of closed tibial fracture. METHODS: The model of closed tibial fracture was established in 40 6-month-old male New Zealand white rabbits with a body weight of 2.5 to 3.0 kg, and the model was verified at 6 weeks after operation. Five rabbits underwent pre modeling without temporary external fixation before modeling, and then were fractured with a modified three-point bending fracture device;35 rabbits underwent formal modeling. Before modeling, needles were inserted, and splints were fixed externally, and then the fracture was performed with a modified three-point bending fracture device. The fracture model and healing process were evaluated by imaging and histopathology at 2 hours, 4 weeks, and 6 weeks after operation. RESULTS: Two hours after modeling, the prefabricated module showed oblique fracture in varying degrees and the broken end shifted significantly;Except for 1 comminuted fracture, 2 curved butterfly fractures and 2 without obvious fracture line, the rest were simple transverse and oblique fractures without obvious displacement in formal modeling group. According to the judgment criteria, the success rate of the model was 85.71%. Four weeks after modeling, the fixed needle and splint of the experimental rabbits were in good position, the fracture alignment was good, the fracture line was blurred, many continuous callus growths could be seen around the fracture end, and the callus density was high. Six weeks after modeling, many thick new bone trabeculae at the fracture, marginal osteoblasts attached, and a small number of macrophages were seen under the microscope. The intramembrane osteogenesis area was in the preparation bone stage, the medullary cavity at the fracture had been partially reopened, the callus was in the absorption plastic stage, and many osteoclasts were visible. The X-ray showed that the fracture line almost disappeared, part of the medullary cavity had been opened, the external callus was reduced around, the callus was in the plastic stage, and the bone cortex was continuous. It suggests that the fracture model showed secondary healing. CONCLUSION The improved three-point bending fracture device can establish a stable rabbit model of closed tibial fracture, and the operation is simple, which meets the requirements of closed fracture model in basic research related to fracture healing.
Rabbits ; Male ; Animals ; Bony Callus ; Fracture Healing ; Tibial Fractures/surgery* ; Osteogenesis ; Radiography

OBJECTIVE: To investigate whether the Runx2 gene can induce the differentiation of human amniotic mesenchymal stem cells (hAMSCs) to ligament fibroblasts in vitro and promote the tendon-bone healing in rabbits. METHODS: hAMSCs were isolated from the placentas voluntarily donated from healthy parturients and passaged, and then identified by flow cytometric identification. Adenoviral vectors carrying Runx2 gene (Ad-Runx2) and empty vector adenovirus (Ad-NC) were constructed and viral titer assay; then, the 3rd generation hAMSCs were transfected with Ad-Runx2 (Ad-Runx2 group) or Ad-NC (Ad-NC group). The real-time fluorescence quantitative PCR and Western blot were used to detect Runx2 gene and protein expression to verify the effectiveness of Ad-Runx2 transfection of hAMSCs; and at 3 and 7 days after transfection, real-time fluorescence quantitative PCR was further used to detect the expressions of ligament fibroblast-related genes [vascular endothelial growth factor (VEGF), collagen type Ⅰ, Fibronectin, and Tenascin-C]. The hAMSCs were used as a blank control group. The hAMSCs, hAMSCs transfected with Ad-NC, and hAMSCs were mixed with Matrigel according to the ratio of 1 : 1 and 1 : 2 to construct the cell-scaffold compound. Cell proliferation was detected by cell counting kit 8 (CCK-8) assay, and the corresponding cell-scaffold compound with better proliferation were taken for subsequent animal experiments. Twelve New Zealand white rabbits were randomly divided into 4 groups of sham operation group (Sham group), anterior cruciate ligament reconstruction group (ACLR group), anterior cruciate ligament reconstruction+hAMSCs transfected with Ad-NC-scaffold compound group (Ad-NC group), and anterior cruciate ligament reconstruction+hAMSCs transfected with Ad-Runx2-scaffold compound group (Ad-Runx2 group), with 3 rabbits in each group. After preparing the ACL reconstruction model, the Ad-NC group and the Ad-Runx2 group injected the optimal hAMSCs-Matrigel compunds into the bone channel correspondingly. The samples were taken for gross, histological (HE staining and sirius red staining), and immunofluorescence staining observation at 1 month after operation to evaluate the inflammatory cell infiltration as well as collagen and Tenascin-C content in the ligament tissues. RESULTS: Flow cytometric identification of the isolated cells conformed to the phenotypic characteristics of MSCs. The Runx2 gene was successfully transfected into hAMSCs. Compared with the Ad-NC group, the relative expressions of VEGF and collagen type Ⅰ genes in the Ad-Runx2 group significantly increased at 3 and 7 days after transfection ( P<0.05), Fibronectin significantly increased at 3 days ( P<0.05), and Tenascin-C significantly increased at 3 days and decreased at 7 days ( P<0.05). CCK-8 detection showed that there was no significant difference ( P>0.05) in the cell proliferation between groups and between different time points after mixed culture of two ratios. So the cell-scaffold compound constructed in the ratio of 1∶1 was selected for subsequent experiments. Animal experiments showed that at 1 month after operation, the continuity of the grafted tendon was complete in all groups; HE staining showed that the tissue repair in the Ad-Runx2 group was better and there were fewer inflammatory cells when compared with the ACLR group and the Ad-NC group; sirius red staining and immunofluorescence staining showed that the Ad-Runx2 group had more collagen typeⅠ and Ⅲ fibers, tending to form a normal ACL structure. However, the fluorescence intensity of Tenascin-C protein was weakening when compared to the ACLR and Ad-NC groups. CONCLUSION Runx2 gene transfection of hAMSCs induces directed differentiation to ligament fibroblasts and promotes tendon-bone healing in reconstructed anterior cruciate ligament in rabbits.
Pregnancy ; Female ; Humans ; Rabbits ; Animals ; Vascular Endothelial Growth Factor A/metabolism* ; Fibronectins/metabolism* ; Collagen Type I/genetics* ; Tenascin/metabolism* ; Collagen/metabolism* ; Anterior Cruciate Ligament/surgery* ; Mesenchymal Stem Cells ; Tendons/metabolism* ; Fibroblasts/metabolism*

Femtosecond laser small incision lenticule extraction (SMILE) with different residual stromal thicknesses (RST) is set to investigate its effect on corneal biomechanical properties of rabbits in vivo. In this study, 24 healthy adult Japanese rabbits were randomly divided into group A and B. The RST of group A was set 30% of the corneal central thickness (CCT), and the RST of group B was 50% of the CCT. The thickness of the corneal cap in both groups was set one third of CCT. Corneal visualization Scheimpflug technology (Corvis ST) and Pentacam three-dimensional anterior segment analyzer were used to determine corneal biomechanical and morphological parameters before surgery, and 1 week, 1 month and 3 months after surgery. Pearson correlation analysis was used to analyze factors affecting corneal biomechanical parameters after SMILE. The results showed that the corneal stiffness of group A was significantly higher than that of group B at 1 week and 1 month after surgery, and most biomechanical parameters returned to preoperative levels at 3 months postoperatively. The results of correlation analysis showed that postoperative CCT and RST were the main factors affecting corneal biomechanical parameters after SMILE. There was no significant difference in corneal posterior surface height (PE) between 3 months after surgery and before surgery in both two groups. It indicates that although the ability to resist deformation of cornea decreases in SMILE with thicker corneal cap and less RST, there is no tendency to keratoconus, which may be related to the preservation of more anterior stromal layer.
Animals ; Biomechanical Phenomena ; Cornea/surgery* ; Postoperative Period ; Rabbits