An experimental drug being tested on dachshunds and other dogs with spinal cord damage may eventually lead to new treatments for people with similar injuries.

The drug, being studied by researchers at the University of California, San Francisco, and Texas A&M College of Veterinary Medicine, has already been shown to help mice with spinal cord injuries walk again. Now researchers plan to study the treatment in dogs that suffer from a relatively common spinal cord injury caused by a ruptured disk.

Such injuries typically occur in short-legged, long-torso breeds of dogs, like dachshunds, beagles, corgis, Pekingese and Shih Tzus, which can lose use of their back legs when a disk ruptures spontaneously and damages the spinal cord. About 2.3 percent of the dogs admitted to veterinary teaching hospitals suffer from this type of injury. Most of these cases involve dachshunds, and one in five dachshunds will suffer such an injury in its lifetime.

The new drug works by blocking a protein that becomes abnormally high immediately after a spinal cord injury. When a spinal cord is injured, some of the damage occurs from the initial trauma, but much of the harm comes later, when a cascade of events that includes chemical reactions, swelling and bleeding causes further damage to the area. The new treatment does not heal the initial injury, but instead interrupts the ensuing cycle of destruction, thereby minimizing the amount of secondary damage to the spinal cord.

U.C.S.F. researchers have shown that the drug can help injured mice walk again if they are treated within three hours of the injury and continue treatment for three days.

“They show a remarkable recovery,’’ said Linda Noble-Haeusslein, professor in the departments of neurosurgery and physical therapy at U.C.S.F. “They go from dragging hind limbs to actually taking functional steps. We can see the benefit as early as one day after the injury.’’

Additional research will try to determine whether mice given the drug more than three hours after the injury may also benefit.

The next step is to test the drug in the real world at the Small Animal Hospital of Texas A&M University, which sees about 120 dogs a year with spontaneous spinal cord injuries. Over the two-and-a-half-year course of the study, the researchers hope to enroll 80 such dogs, with their owners’ consent, in a randomized clinical trial in which all the dogs will receive surgical treatment and rehabilitation for the injury.

Some dogs will be given the experimental drug, others will receive a placebo, and another group will be given use of a wheeled device to help with walking. Because some pet owners may not be able to take the dog to the vet within three hours of the injury, the study will also examine the effect of the drug if given 6 to 12 hours after the initial injury.

If the drug is shown to be effective in dogs, it is expected that the scientists will move to begin studying the drug in humans within a year or two after the end of the dog trial.