Maintenance of contractile function of isolated airway smooth muscle after cryopreservation.

This research focuses on perfecting methods to cryostore isolated human airway smooth muscle tissues, important for understanding respiratory diseases. Researchers tested multiple cryostorage protocols and present one that allows the tissues to maintain most of their contractile function.

Overview of Research

The study conducted a comprehensive exploration of several protocols for freezing and storing isolated airway smooth muscle (ASM), focusing on human and equine trachealis ASM. These muscles are integral to understanding various respiratory diseases, hence the importance of preservation for study. Lack of availability and high cost called for robust storage options.

Cryostorage Protocols

• The research team tested different cryostorage media: 1.8 M dimethyl sulfoxide with fetal bovine serum (FBS) or Krebs-Henseleit solution (KH).
• The tissues were also tested at differing levels of dissection, either with epithelium and connective tissues attached or without.
• Contractility responses to drugs (methacholine, histamine, and isoproterenol) and electrical field stimulation were measured before and after cryostorage.

Results of the Cryostorage

• Evidence showed that maximal stress response to methacholine decreased more in dissected equine tissues than in intact ones.
• EFS force decreased in all equine cryostored tissues, whereas the human tissues showed no similar decline.
• Maximal shortening velocity due to EFS was reduced in human cryostored tissues, and isoproterenol response was potentiated after cryostorage.
• Overnight incubation with 0.5 or 10% FBS did not recover contractility in equine tissues, but it did potentiate the Iso response.
• In human tissues, overnight incubation with 10% FBS led to maximal stress recovery and maintenance of other contractile parameters.

Recommended Protocol

Based on their findings, the researchers proposed an optimal protocol for cryostorage. This involves storing ASM as undissected tissues in FBS or KH solution, followed by dissection of the ASM bundles and a 24-hour incubation with 10% FBS before conducting measurements. This protocol enables the isolated ASM tissues to retain most of their contractile function even after cryostorage. The results of this research can be beneficial in numerous future studies involving the use of human airway smooth muscle tissues.