Hydrogel, Inspired by Cow Slime, Could Transform Surgery for Slipped Discs

Researchers at Uppsala University have developed a synthetic mucin gel inspired by cow slime. They say the gel could reduce the risk of long-term complications and improve surgical outcomes for patients.

Their study was published in Advanced Science.

Current treatments fail to prevent recurrence

A disc herniation, commonly referred to as a slipped disc, occurs when the soft tissue between the vertebrae bulges out due to damage. This can compress nearby spinal nerves, leading to significant pain and discomfort. It’s estimated one to three percent of people in Western, industrialized countries will experience pain from a slipped disc at some point in their lives.

Initial treatment for disc herniation typically focuses on symptom management through painkillers and steroid injections. For those whose pain persists beyond three weeks, physical therapy is often recommended. In some cases, surgery may be required to remove the herniated disc and relieve pressure on the spinal nerves. Unfortunately, these treatments often fail to address the underlying structural issues or prevent recurrence. Additionally, no current treatments stop the immune system from attacking residual disc tissue, which can aggravate the injury.

Most current research is aimed at regenerating damaged discs rather than preventing further injury. However, since discs lack blood vessels, contain few cells and endure constant physical stress, these regenerative approaches remain challenging.

Using cattle saliva to suppress immune activation

The Uppsala researchers developed a synthetic mucin hydrogel inspired by the mucus coating of certain parasites, which helps the gel evade the immune system. The mucin-derived gels (Muc-gels) were synthesized using bovine submaxillary mucin (BSM) – large glycoproteins derived from the salivary glands of cattle. BSMs are becoming increasingly popular as building blocks for novel biomaterials and have been shown to suppress immune cell activation upon viral exposure.

The hydrogel was applied to the surgical site in animal models via injection, solidifying in three-to-five minutes. Encapsulating the spinal disc in Muc-gel formed a physical and immune barrier, which prevented immune cells from attacking the leftover disc tissue, resulting in tissue degeneration. The models that underwent the procedure retained biomechanical properties similar to those of healthy discs. Traditional physical barriers, such as alginate gels, were unable to provide the same level of protection when compared to the Muc-gels. Injection of the hydrogel prevented disc degeneration for up to 24 weeks post-operation.

Translating their findings into a clinical setting

“This approach could have a major impact on surgical procedures, as a simple injection of mucin gels at the surgical site could improve patient outcomes, reduce the risk of long-term complications and increase the overall success rate of disc surgery,” said co-corresponding author Dr. Hongji Yan, a researcher in the department of medical cell biology at Uppsala University.

Further research is needed to be able to translate the researchers’ findings into a clinical setting. Yan and the team plan to conduct a follow-up study in a large animal model to determine whether their results can be replicated, in addition to further investigations into compressive loading and tensile loading in ex vivo mechanical testing.

“This new approach offers hope for those suffering from back pain caused by disc herniation and may prevent further damage after removing herniated discs, potentially improving the quality of life for the patients,” said Yan.

Reference: Wang H, Chen S, Liu Z, et al. Preserving the immune-privileged niche of the nucleus pulposus: safeguarding intervertebral discs from degeneration after discectomy with synthetic mucin hydrogel injection. Adv Sci. 2024:2404496. doi: 10.1002/advs.202404496

This article is a rework of a press release issued by Uppsala University. Material has been edited for length and content.