Chapter 2168: Chapter 1426: Surprise
Manstein crouched in the animal room for a long time, so long that when Fritz returned from the low-temperature freezer room, he thought Manstein had fallen asleep.
"Manstein?" Fritz stood at the door, holding a frost-covered foam box, "Are you okay?"
Manstein stood up, his knee clicking. He stretched his numb leg and took the foam box from Fritz’s hand. "All of M21’s tissues are here?"
"All here, seventeen wax blocks, eight tubes of frozen tissues, and three slides not fully stained yet." Fritz opened the foam box, neatly packed inside were the labeled embedding boxes and centrifuge tubes, "What do you need me to do?"
"Re-slice, re-stain, use double labeling with Dibutylyte and NeuroD, and add DAPI for nuclear staining. I want to see clearly what these cells really are."
Fritz did not ask why, having collaborated with Manstein for years, he was already accustomed to such sudden instructions. He simply nodded, took the foam box from Manstein’s hand, and turned towards the tissue section room. After two steps, he stopped, turned back to glance at Manstein.
"Manstein, have you discovered something?"
"Maybe I have, maybe not, I’ll tell you after I see the staining results."
Fritz did not ask further, he walked into the tissue section room and closed the door. Manstein stood in the middle of the animal room, looking around. M7 turned over in its cage, switching from lying belly-up to lying on its side, its hind leg kicking once in its sleep, as if walking. In the surrounding cages were several other experimental monkeys, some sleeping, some idly gripping the bars, with no interest in Manstein’s presence. The innermost cage was now empty, it was M8’s. M8 was moved to the post-operative observation room yesterday, its spinal cord was sliced into thousands of thin sections, stored in a minus eighty-degree freezer, waiting to be interpreted layer by layer by Manstein.
And M21, the "surprise," had completed its experimental journey months ago. On the day it was euthanized, Fritz stayed alone in the animal room for a long time. He crouched in front of M21’s cage, muttered something softly in German, then cleaned the cage thoroughly, making it look like new. When Manstein entered the animal room, Fritz was pushing M21’s cage to the corner. Manstein asked what he was doing, Fritz replied, "Making space, M21 won’t be coming back." Manstein did not stop him, but also never let a new monkey live in that cage. The cage remained empty, with a label on the door, inscribed "M21."
An empty cage is harder to bear than a full one.
Manstein walked to where M21’s cage once stood, and lingered for a while. The handwriting on the label was Fritz’s, neat and clear, every letter written meticulously. "M21. Non-targeted intervention group. Unexpected recovery." Unexpected recovery. Manstein stared at these four words, suddenly feeling they were inaccurate. This was not unexpected. M21’s recovery was the same as M7’s recovery, the same as Chen Jianguo’s recovery, all different manifestations of the same biological law. They merely took longer to understand what M21 was telling them.
M21 had been an outlier from the beginning. In the non-targeted intervention group, it was the only monkey to show functional recovery. The other five showed nothing, myoelectric signals were flat, behavioral scores were zero, anatomical examinations revealed no signs of repair bridging or regenerative substitution. Only M21 exhibited voluntary contraction of hind leg muscles from the sixteenth week post-operation, regained autonomous urination by the twenty-second week, and stood with assistance by the twenty-eighth week. Manstein did not know how to explain this phenomenon at the time. 62% of targeted intervention group monkeys recovered functionally, while only M21 did in the non-targeted group. Statistically this is an "anomaly," biologically it’s "worth investigating."
After leaving the tissue section room, Manstein went straight to Yang Ping’s office.
Yang Ping was resting.
"What’s up?"
"Professor, I need you to confirm something for me."
"What is it?"
Manstein walked in and opened the folder, inside was a stack of printed micrographs. He spread out the photos on Yang Ping’s desk, lining them up. Each photo was an immunofluorescent stained image of spinal cord tissue sections, red Dibutylyte marked nascent neural precursor cells, green NeuroD marked differentiating neurons, and blue DAPI marked all cell nuclei.
"These are M21’s spinal cord sections, I had Fritz re-stain them using double labeling with Dibutylyte and NeuroD." Manstein pointed at the first photo, "Look at the area surrounding the damage."
Yang Ping leaned in, carefully observing the photos. Around the center of the damage, along the pathway of blood vessels, densely distributed red and green fluorescent signals. Red and green combined to form yellow, which was the area of Dibutylyte and NeuroD co-expression, migrating, differentiating neural precursor cells.
"This is almost identical to M8’s sections." Yang Ping said.
"Almost identical, M21 didn’t receive precise gene editing, we merely performed a broad microenvironment adjustment, without using targeted vectors. Yet its spinal cord showed activation of precursor cells all the same. This indicates that precursor cell activation does not require precise gene editing, merely a growth-permitting microenvironment, and the substances that initiate this behavior exist within the microenvironment."
