LSJL Studies 2: Effect of holes on LSJL

Not a lot on this study relating to longitudinal bone growth.  The important takeaway is evidence that LSJL can cause bone degradation which would be an important part of the process for neo-growth plate formation.

Effects of surgical holes in mouse tibiae on bone formation induced by knee loading.

“Loads applied directly to the knee (knee loading) have induce anabolic responses in femoral and tibial cortical bone. In order to examine the potential role of intramedullary pressure in generating those knee loading responses, we investigated the effects of drilling surgical holes that penetrated into the tibial medullary cavity and thereby modulated pressure alteration. Thirty-nine C57/BL/6 female mice in total were used with and without surgical holes, and the surgical holes were monitored. The left knee was loaded for 3 days[at 5Hz at 0.5N for 3 min a day], and the contralateral limb was treated as a sham-loaded control. Mice were sacrificed 2 weeks after the last loading. Although the surgical hole induced bone formation in both loaded and non-loaded tibiae, due to regional and systemic acceleratory phenomenon the anabolic effect of knee loading was substantially diminished. Without the holes, knee loading significantly elevated cross-sectional cortical area, cortical thickness, mineralizing surface, mineral apposition rate, and bone formation rate on the periosteal surface. For example, the rate of bone formation was elevated 2.1 fold (middle diaphysis–50% site from the knee along the length of tibiae) and 2.7 fold ( distal diaphysis–75% site). With the surgical holes  knee loading did not provide significant enhancement either at the 50% or 75% site in any of the histomorphometric measurements. Alteration of intramedullary pressure is necessary for knee loading to induce bone formation in the diaphysis{it may also be necessary to induce longitudinal bone growth} .”

Now they do say however that the drilling of the epiphysis did induce a response of the bone just not the same adaptations as it did without drilling.  Note that drilling was used rather than microfracture.  Although we can’t say for sure how surgical holes would affect LSJL’s effects on longitudinal bone growth.

“On days 2 and 6 after the last loading, the mice were given an intraperitoneal injection of calcein” and the results are shown below.  Calcein is used as a Ca2+ and Mg2+ indicator which are two proteins that are strong components of bone.

Without drilling:

Note that in group D which is the loaded group there is a huge hole in the middle of bone indicating that LSJL may in fact cause bone degradation which would allow for cartilagenous growth plates.  The fluid flow degrades bone and osteomy(removal of bone) may be necessary for new chondrogenesis.  It’s possible that this degradation of bone occurs in the epiphysis as well.  In group F the hole is smaller.  Group F was farther away from the site of loading than group.  Perhaps LSJL induces bone degradation more at sites closer to loading rather than farther away from loading.
  Slides were only taken from above so it’s possible that there would be bone degradation visible if the bone was horizontally sliced.  Bone degradation from a horizontal degradation would be ideal to allow for new growth plate formation for renewed longitudinal bone growth.
With drilling:
In this group both C and D have holes but in group F versus E the hole is much bigger in F.  In D the bone degradation is much more scattered than in C.  So LSJL can increase bone degradation in the body.
Unfortunately this study was performed before Yokota and Zhang realized that Lateral Synovial Joint Loading could be used to increase bone length so they didn’t measure the things that would interest us height seekers like if the tibia and femur had increased in length.

” knee loading induces alteration of intramedullary pressure in the femoral bone cavity and this alteration is synchronous to the loading frequency in Hz”<-The higher the frequency, the greater the intramedullary pressure.  I’m not sure exactly how to alter the frequency via LSJL but I believe that clamping/release from clamping/and then clamping again.

“cyclic deformation of the epiphysis alters pressure in the medullary cavity and the pressure gradient induces fluid flow in the diaphysis “<-Although fluid flow which can increase nutrient supply to chondrocytes, the number of changes induced to the growth plate via LSJL cannot be explained by just an increase in nutrient.

“In the presence of surgical holes, it is expected that the gradient is not adequately established because of incomplete pressure sealing.”

“A pressure gradient, elevated by venous ligation, was shown to increase interstitial fluid flow and this flow-mediated bone adaptation was considered to be independent of mechanical strain ”

“During knee loading no bruising or other damage was detected at the loading site, and after loading mice did not show a weight loss or a diminished food intake.”

“Osteoblast specific factor 2 (periostin) is preferentially expressed on periosteum and considered to play a role in the recruitment and attachment of osteoblast precursors in the periosteum”

“knee loading herein induces approximately 30 μstrain at the site of bone formation and the number of loading cycles per day is 900 for 3 days”

3 thoughts on “LSJL Studies 2: Effect of holes on LSJL

  1. Pingback: Another potential LSJL design mentioned in a scientist paper - Natural Height Growth

  2. Vinayak

    But still the loading only changes the microenvironment of cancellous bone not the cortical bone….even if by loading on the knee region and degarading the cancellous bone near to the loaded area…the growth plates then formed would only grow cancellous bone whereas the cortical bone does not get altered or added longitudinally due to the fact that it was not degraded by LSJL and thus no growth plate was formed between the cortical bone area…..the growth plate as mentioned would only be formed in the cancellous bone area….thus not effecting height (this is only my opinion, i am not here to make people or you lose hope….just please think about what i commented and reply to me if i am wrong or right and how the problem could be solved )

    Reply

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