HISTOLOGICAL, IMMUNOLOGICAL, AND BIOCHEMICAL RESPONSES TO SUBCUTANEOUS INJECTION OF A COMBINED HYDROGEL SCAFFOLD DESIGNED FOR DENTAL CANALS IN MICE

Biocompatibility does not mean the absolute lack of cytotoxicity. If the implant
material performs its function in the body and keeps the interaction between the material and the cell in the
body and the organ maintains its normal function, in a way that the general reaction of the body is normal,
then we can say the material is biocompatible. The aim of this study was to evaluate the histological,
immunological, and biochemical effects of collagen + PCL-PEG-PCL, gelatin + PCL-PEG-PCL, and alginate
+ PCL-PEG-PCL in mice after 30 days of subcutaneous injection.
Materials & Methods: The scaffolds were prepared by freeze-thinning and characterized using FTIR
methods. A 500 μl hydrogel scaffold was injected into the dorsal flank region of a Swiss CD1mouse. Animals
were divided into control, collagen + PCL-PEG-PCL, gelatin + PCL-PEG-PCL, and alginate + PCL-PEG-
PCL groups. The mice were euthanized after 30 days to investigate the biocompatibility of the scaffold with
the use of antidiabetic drugs. Skin, liver, and kidney were sampled for histopathological investigation, gene
expression, and enzyme expression.
Results: In this study, a hybrid hydrogel scaffold was well-constructed and characterized. The ratio of
aspartate aminotransferase (AST) to alanine aminotransferase (ALT) can distinguish liver damage from other
possibilities. In the enzymatic study, the ratio of AST to ALT in the alginate + PCL-PEG-PCL group was
higher than the others (2.9 times more than that of the control group). Despite the differences between the
groups (blood biochemical analysis), no significant differences were observed in the enzymatic study
between the groups. In the present study, in the control and collagen + PCL-PEG-PCL groups, the expression
level of interleukin 10 gene was four times lower than the alginate + PCL-PEG-PCL and gelatin + PCL-PEG-
PCL groups, and the findings showed significant differences (p <0.001). SOD, CAT, and CD31 genes in the
PCL-PEG-PCL + alginate group showed 10.8, 3.3, and 3.5 times more expression than the beta-actin gene,
respectively, and demonstrated significant differences compared to the other groups (p <0.001). In
histopathological examination of external examination and macroscopic examination of organs, there was no
indication of systemic complications such as shock, septicemia, toxemia, or extensive inflammatory reactions
in any of the groups.
Conclusion: According to the results of this study, it can be concluded that the combination scaffold of
collagen + PCL-PEG-PCL has fewer complications than other groups. The scaffold (collagen + PCL-PEG-
PCL) is likely to be biocompatible and has the potential for future studies to transfer the d