Regional-specific meniscal extracellular matrix hydrogels and their effects on cell-matrix interactions of fibrochondrocytes

Decellularized meniscal extracellular matrix (ECM) material holds great potential for meniscus repair and regeneration. Particularly, injectable ECM hydrogel is highly desirable for the minimally invasive treatment of irregularly shaped defects. Although regional-specific variations of the meniscus are well documented, no ECM hydrogel has been reported to simulate zonally specific microenvironments of the native meniscus. To fill the gap, different (outer, middle, and inner) zones of porcine menisci were separately decellularized. Then the regionally decellularized meniscal ECMs were solubilized by pepsin digestion, neutralized, and then form injectable hydrogels. The hydrogels were characterized in gelation behaviors and mechanical properties and seeded with bovine fibrochondrocytes to evaluate the regionally biochemical effects on the cell-matrix interactions. Our results showed that the decellularized inner meniscal ECM (IM) contained the greatest glycosaminoglycan (GAG) content and the least collagen content compared with the decellularized outer meniscal ECM (OM) and middle meniscal ECM (MM). The IM hydrogel showed lower compressive strength than the OM hydrogel. When encapsulated with fibrochondrocytes, the IM hydrogel accumulated more GAG, contracted to a greater extent and reached higher compressive strength than that of the OM hydrogel at 28 days. Our findings demonstrate that the regionally specific meniscal ECMs present biochemical variation and show various effects on the cell behaviors, thus providing information on how meniscal ECM hydrogels may be utilized to reconstruct the microenvironments of the native meniscus.

Effect of Hydrogen Peroxide Pretreatment on Physiological and Biochemical Variables during Germination of Alfalfa Seeds

Background: Hydrogen peroxide is reactive oxygen species that plays role in plant response to biotic and abiotic stress. The pretreatment with hydrogen peroxide can confer an adaptive capacity for the plants in unpredictable environments. The alfalfa (Medicago sativa L.) is the legume more utilized in animal feeding in the world. Moreover, the alfalfa sprouts are known for the phytochemicals that promote health with antioxidant properties. Methods: This work aimed to determine the effect of hydrogen peroxide in the pretreatment process of alfalfa seeds on variables as total germination, speed of germination, activity and antioxidant enzymes. The alfalfa seeds were soaked for 12 h in the next treatments 0, 98, 294, 490, 784, 980 mM of hydrogen peroxide. Result: The results showed that total germination was higher with the hydrogen peroxide than with water except 980 mM. The results of the present research indicated that hydrogen peroxide had physiological and biochemical effects on the germination processes of alfalfa.